CN101437758B - Method of reducing calcia concentrations of green bayer process liquors - Google Patents
Method of reducing calcia concentrations of green bayer process liquors Download PDFInfo
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- CN101437758B CN101437758B CN200780016077.6A CN200780016077A CN101437758B CN 101437758 B CN101437758 B CN 101437758B CN 200780016077 A CN200780016077 A CN 200780016077A CN 101437758 B CN101437758 B CN 101437758B
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- phosphatic
- calcium oxide
- bayer liquors
- unprocessed
- red mud
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B25/00—Phosphorus; Compounds thereof
- C01B25/16—Oxyacids of phosphorus; Salts thereof
- C01B25/26—Phosphates
- C01B25/32—Phosphates of magnesium, calcium, strontium, or barium
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F7/00—Compounds of aluminium
- C01F7/02—Aluminium oxide; Aluminium hydroxide; Aluminates
- C01F7/04—Preparation of alkali metal aluminates; Aluminium oxide or hydroxide therefrom
- C01F7/06—Preparation of alkali metal aluminates; Aluminium oxide or hydroxide therefrom by treating aluminous minerals or waste-like raw materials with alkali hydroxide, e.g. leaching of bauxite according to the Bayer process
- C01F7/062—Digestion
- C01F7/0633—Digestion characterised by the use of additives
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F7/00—Compounds of aluminium
- C01F7/02—Aluminium oxide; Aluminium hydroxide; Aluminates
- C01F7/04—Preparation of alkali metal aluminates; Aluminium oxide or hydroxide therefrom
- C01F7/06—Preparation of alkali metal aluminates; Aluminium oxide or hydroxide therefrom by treating aluminous minerals or waste-like raw materials with alkali hydroxide, e.g. leaching of bauxite according to the Bayer process
- C01F7/0646—Separation of the insoluble residue, e.g. of red mud
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F7/00—Compounds of aluminium
- C01F7/02—Aluminium oxide; Aluminium hydroxide; Aluminates
- C01F7/46—Purification of aluminium oxide, aluminium hydroxide or aluminates
Abstract
A method of reducing the calcia concentration of a green Bayer process liquor containing calcia and phosphate, the method comprising the step of: contacting the green Bayer process liquor with a quantity of apatite; thereby inducing the precipitation of further apatite and reducing the calcia concentration of the green Bayer process liquor.
Description
Technical field
The present invention relates to reduce the method for calcium oxide concentration in the solution that produces when from aluminium ore, producing aluminum oxide by Bayer process.Especially, the present invention relates to reduce the method for calcium oxide concentration in the unprocessed bayer liquors (green Bayer process liquors).
Background technology
Bayer process is widely used in producing aluminum oxide from salic ore (for example, bauxite).At first in being commonly referred to as the technique of stripping, under the rising temperature, the ore that will contain aluminum oxide contacts with the sodium aluminate solution of regeneration the method.
After the stripping, a series of decompression tanks (being known as blowdown vessel) of flowing through of the insoluble red mud slurry in the sodium aluminate solution (unprocessed solution), this solution is down to suddenly normal atmosphere at this tank place.In the method next step is that insoluble red mud is separated from sodium aluminate solution.Thick material may be removed in being known as the crude oil swirler of sand-settling device, and thin residue is stayed in the rake thickener after adding synthetic flocculant.Red mud is taken as the underflow of thickner, and then common flushing red mud is to recover the alkalescence value and to make it be suitable for processing.Yet overflow still contains superfine red mud particle usually, comprises ferric oxide, ironic hydroxide, silicon-dioxide etc.The existence of these compounds in the aluminum oxide end product do not expect that very the one or more strainers of the common process of sedimentation tank overflow are to remove them.
Clear soln is further cooled off in heat exchanger, and this improves the degree of supersaturation of the aluminum oxide of dissolving, and solution is pumped to settling vessel and then sows to induce more aluminum hydroxide precipitation with aluminium hydroxide.Isolate the aluminium hydroxide of precipitation from sodium aluminate solution, a part of aluminium hydroxide is recycled as crystal seed, and residuum is recovered as product.Remaining sodium aluminate solution is recycled the further stripping for salic ore.
Dissolving-out process consumes oxyhydroxide, and it replenishes (at least part of) usually again by adding lime.The calcium oxide that mode by lime is introduced into is can calcium carbonate form precipitated.Yet, can realize more effective causticization by adding excessive lime, this means that the calcium oxide concentration in the solution increases.
Obviously, for effective precipitation, wish very much to want high with respect to total alkali concn alumina concentration.Yet, do not wish that equally any aluminum oxide that has dissolved precipitates before filtration.Except lowering efficiency, this has reduced the time that the strainer maintenance can be turned round.The maintenance needs of strainer depends on employed filter type, opens filter assemblies, removes solid and with the cleaning waste liquid filter media that backwashes but generally include.This causes sizable interference to most of continuous processing in addition, and needs considerable work.Therefore, most of refineries usually determine the critical ratio of an alumina concentration and total alkali concn, are higher than this value and then filter and just become infeasible.For example by adding lime or calcite, perhaps in other cases, for example organic concentration raises in the solution, and/or for example side effect of other factory technics, the rising of unprocessed solution (or slurries) calcium oxide concentration has increased the stability of aluminum oxide, filters under the ratio of higher aluminum oxide/total alkali (caustic) with permission.
Yet calcium oxide concentration height can show the problem of a product quality in the solution: calcium oxide is removed quantitatively by the hydration precipitation, and is retained by calcining, so that about 100% calcium oxide finally is reported as the product aluminum oxide in the solution.Therefore, the technology that those cause calcium concn in the solution to improve is for example used stabilization and the causticization (causticisation) of the aluminum oxide of superfluous lime, can not bring into play fully they potential and not negative impact product quality.
Therefore, be starved of the method that some reduce calcium oxide in the bayer liquors.
Background of the present invention previously discussed is intended to help to understand the present invention.Yet, should be appreciated that this discussion be not think or when admitting that any indication content is priority date in the conventional knowledge of Australia.
Summary of the invention
It will be appreciated by those skilled in the art that invention described herein is easy to change and the modification except the content that specifies.Should understand and the present invention includes all such changes and modifications.The present invention also comprise indication in the specification sheets or the institute that hints in steps, feature, composition and compound, and with separately or integrally and the mode of any and all combinations of any two or more steps or feature.
The invention is not restricted to the scope of embodiment as herein described.They only are used for the purpose of illustration.
The product of function equivalent, composition and method are obviously within the scope of the invention.
Whole disclosures of all publications that this paper quotes (comprising patent, patent application, magazine article, laboratory operation guide, book or other file) are introduced into this paper as a reference at this.
In the whole specification sheets, unless context has needs in addition, word " all comprises " or its distortion " comprises " or " having comprised " will be understood to hint and comprise pointed whole or whole collection and do not get rid of any other whole or whole collection.
In the whole specification sheets, unless context has needs in addition, word " phosphatic rock " refers to based on hydroxylapatite (Ca
10(PO
4)
6OH
2) a compounds in one or more, comprise fluorapatite (Ca
10(PO
4)
6F
2), chlorapatite ((Ca
10(PO
4)
6Cl
2), hydroxylapatite (Ca
10(PO
4)
6OH
2), phosphatic rock carbonate, hydroxylapatite carbonate or fluorapatite carbonate.The phosphatic rock of most forms can pass through following general formula A
10(XO
4)
6(OH, F, Cl)
2.nH
2O describes, and wherein: A can be selected from Ba, Ca, Ce, K, Na, Pb, Sr, Y; X can be selected from As, P, Si, V and PO
4Can be at least part of by CO
3Replace.
In the whole specification sheets, unless context has needs in addition, word " phosphatic rock " has comprised the mixture that contains phosphatic rock, and it comprises the mixture that contains one or more phosphatic rock.
According to the present invention, provide and reduce the method that contains calcium oxide concentration in calcium oxide and the phosphatic unprocessed bayer liquors, the method comprises the steps:
To contain calcium oxide contacts with a certain amount of phosphatic rock with phosphatic unprocessed bayer liquors;
Thereby impel the precipitation of further phosphatic rock and reduce the concentration that this contains calcium oxide in calcium oxide and the phosphatic unprocessed bayer liquors.
Phosphatic rock can have following general formula A
10(XO
4)
6(OH, F, Cl)
2.nH
2Any compound form of O provides, and wherein: A can be selected from Ba, Ca, Ce, K, Na, Pb, Sr, Y; X can be selected from As, P, Si, V, and PO
4Can be by CO
3Replace.
Preferably, A is that Ca and Na and phosphatic rock at least mainly provide with hydroxylapatite carbonate or with any mixture of this compound, and this hydroxylapatite carbonate has general formula Ca
10-xNa
2x/3(PO
4)
6-x(CO
3)
x(OH)
2-x/3.xH
2O, wherein, 0≤x≤3.
A kind of form of the present invention, phosphatic rock is with Ca
7Na
2(CO
3)
3(PO
4)
3(H
2O)
3(OH) form provides.
Yet scope of the present invention should not be understood to be limited to hydroxylapatite carbonate, because verified such as Ca
5(PO
4)
3(OH) hydroxylapatite noncarbonate is effective.
Usually can situ production phosphatic rock in many Bayer process refinery, this provides other advantage of the present invention.
For example, can prepare phosphatic rock by interpolation lime source and phosphate source in bayer liquors.A kind of form of the present invention, the lime source provides with the form of white lime, tricalcium aluminate or filter pressing sludge.Phosphate source and bayer liquors can high phosphate Bayer process waste liquid form provide together.In about 90 ℃ temperature, very short for the preparation of the residence time of phosphatic rock, about 15-30min.The phosphatic rock of so producing can be separated from this solution before being used for method of the present invention.Perhaps, the slurries of phosphatic rock and upper solution can be used for method of the present invention.
The preparation method that has been found that phosphatic rock affects phosphatic rock effectiveness in the methods of the invention.Particularly, more effective with the phosphatic rock of the excessive phosphoric acid salt of stoichiometry preparation, it is excessive to provide larger effectiveness more at most.Therefore, in the preferred form of the present invention, the phosphoric acid salt excessive with stoichiometry prepares phosphatic rock.Yet residual phosphate concn can cause other process complexity after the phosphatic rock precipitation.Therefore, in the preferred form of the present invention, use less than the excessive phosphoric acid salt of 200% stoichiometry to prepare phosphatic rock.In the preferred form of the present invention, use less than the excessive phosphoric acid salt of 100% stoichiometry to prepare phosphatic rock.In the preferred form of the present invention, use less than the excessive phosphoric acid salt of 50% stoichiometry to prepare phosphatic rock.
In addition, have been found that phosphatic rock effectiveness in the methods of the invention reduces in time.Therefore, the preferred new precipitation of a certain amount of phosphatic rock, or at least from will newly being separated the solution of its precipitation.In the highly preferred form of the present invention, the method according to this invention, phosphatic rock its with 24h before unprocessed bayer liquors contacts in precipitated.Yet the time, longer phosphatic rock can be used for favourable processing condition, for example, and high density oxidation calcium and phosphatic feed solution.Also preferred, the method according to this invention, phosphatic rock its with 8h before unprocessed bayer liquors contacts in precipitated.
In addition, the phosphatic rock that has been found that precipitation can be enhanced by a certain amount of phosphatic rock is exposed in the phosphate solution in the effectiveness of the inventive method.Have been found that replenishing active degree depends on the concentration of phosphate solution and expose the time length, longer and more the replenishing of the larger then generation of phosphate solution concentration of open-assembly time.As an example, chronic phosphatic rock is exposed to activity that the about 15min of 9000ppm phosphate solution will recover phosphatic rock approximately to half of the phosphatic rock activity of new precipitation to 1/3rd.
Having been found that affects the reduction degree of calcium oxide concentration the duration of contact (residence time) of bayer liquors and a certain amount of phosphatic rock, and residence time is longer usually causes the calcium oxide minimizing more.Therefore, reduce by balance oxidation calcium and be combined the other factors of Bayer process with the effect of the inventive method and obtain preferred residence time.Yet, use the very short time can realize that also effective calcium oxide reduces, in many preferred implementations of the present invention, the requirement that does not apply extra residence time in conjunction with existing Bayer process step namely can realize the method.
Have been found that a certain amount of phosphatic rock that joins in the bayer liquors affects the reduction degree of calcium oxide concentration, dosage is larger more remarkable and/or rapider on the impact that reduces.In addition, different dosage is suitable for different methods that unprocessed bayer liquors is contacted with a certain amount of phosphatic rock.The below discusses the different methods that unprocessed bayer liquors is contacted with a certain amount of phosphatic rock.Yet, should be enough with the dosage of 200-300g phosphatic rock/kL bayer liquors magnitude for the scope for the treatment of condition.Lower dosage is possible under favourable treatment condition (for example calcium oxide of high density and phosphatic feed solution).
Have been found that the phosphate concn in the unprocessed bayer liquors affects the reduction degree of calcium oxide concentration, concentration is higher more remarkable and/or rapid on the impact that reduces.Yet as skilled in the art to understand, high phosphate concentration has been introduced the shortcoming relevant with technique, and these shortcomings may surpass calcium oxide and reduce the advantage that realizes.Phosphate concn in the common unprocessed bayer liquors extremely surpasses 400ppm from about 40ppm noticeable change in the total alkaline solution of height.
Have been found that the reduction degree of the calcium oxide concentration affects calcium oxide concentration in the unprocessed bayer liquors, concentration is higher more remarkable and/or rapid on the impact that reduces.
Have been found that the reduction degree of the temperature effect calcium oxide concentration of unprocessed bayer liquors, temperature is higher more remarkable and/or rapid on the impact that reduces.Yet as skilled in the art to understand, the temperature variation of bayer liquors is the high energy consumption process, and the economical disadvantages that temperature raises may surpass the economical advantage that is obtained to optimize method of the present invention by the temperature that changes bayer liquors.
The present invention is in the lower outstanding work of typical bayer liquor filtration temperature (100-105 ℃), but also can be lower application of wide temperature range (70 ℃ and more than).Although lower temperature causes slower deliming speed, this can compensate by controlling other process variable (for example, calcium and phosphate concn, residence time in phosphatic rock dosage and granularity, the feed solution).
Have been found that the reduction degree of the particle size influences calcium oxide concentration of a certain amount of phosphatic rock, granularity is less more remarkable and/or quick on the impact that reduces.Yet in forms more of the present invention, a certain amount of phosphatic rock contacts with unprocessed bayer liquors from solid-solution separating step upstream.The below discusses the example of these forms of the present invention.In these forms of the present invention, the lower limit that solid-solution separating step can given phosphatic rock desired particle size, at least basically separated very essential from solution in solid-solution separating step because this is phosphatic rock.
The beneficial effect that particle diameter reduces is considered to depend at least significantly the surface-area of increase, and surface-area is larger, and is more remarkable and/or quick on the impact that reduces.Therefore, in the preferred form of the present invention, a certain amount of phosphatic rock comprises the phosphatic rock with high surface area/volume ratio.Increase the surface-area of a certain amount of phosphatic rock and do not reduce granularity, perhaps by at least disproportionately reducing granularity, provide benefit to more remarkable and/or fast reducing calcium oxide concentration, and do not cause or do not cause latent defect in solid-solution separating subsequently with proportional degree.
Therefore, have been found that the method according to this invention removes the effectiveness of calcium oxide and be subjected to following the impact:
(i) prepare phosphatic rock with the excessive phosphoric acid salt of stoichiometry, with regard to the degree of removing calcium oxide or can be at a time between in realize removing with regard to time of calcium oxide of expected degree, excessive more, larger effectiveness is provided;
(ii) phosphate concn of unprocessed bayer liquors, with regard to the degree of removing calcium oxide or can be at a time between in realize removing with regard to time of calcium oxide of expected degree, phosphate concn is higher, and larger effectiveness is provided;
(iii) the calcium oxide concentration of bayer liquors, with regard to the degree of removing calcium oxide or can be at a time between in realize removing with regard to time of calcium oxide of expected degree, calcium oxide concentration is higher, and larger effectiveness is provided;
The dosage of the phosphatic rock that (iv) contacts with bayer liquors, with regard to the degree of removing calcium oxide or can be at a time between in realize removing with regard to time of calcium oxide of expected degree, dosage is higher, and larger effectiveness is provided;
(v) time of contacting with unprocessed bayer liquors of a certain amount of phosphatic rock, with regard to the degree of removing calcium oxide, the time is longer, and larger effectiveness is provided;
Particle diameter and/or the surface-area of the phosphatic rock that (vi) contacts with unprocessed bayer liquors, with regard to the degree of removing calcium oxide or can be at a time between in realize removing with regard to time of calcium oxide of expected degree, particle diameter is less and/or surface-area is larger, and larger effectiveness is provided;
(vii) temperature that contacts with unprocessed bayer liquors of a certain amount of phosphatic rock, with regard to the degree of removing calcium oxide or can be at a time between in realize removing with regard to time of calcium oxide of expected degree, temperature is higher, and larger effectiveness is provided; With
The degree of aging (age) of a certain amount of phosphatic rock that (viii) contacts with unprocessed bayer liquors, with regard to the degree of removing calcium oxide or can be at a time between in realize removing with regard to time of calcium oxide of expected degree, provide larger effectiveness with the phosphatic rock of new precipitation and/or the phosphatic rock that newly contacts with phosphate solution.
By the requirement of the other side defined of Bayer process limit one or whole above-mentioned mention factor to optimized degree to be implemented in the exact level of removing calcium oxide in the specific Bayer process refining.Combination and/or optimization to one or more factors of particular case are considered to fall within the scope of the present invention.
Title is for having discussed some combinations of phosphate concn, calcium oxide concentration, temperature, particle diameter, granule surface area, phosphatic rock preparation condition, phosphatic rock degree of aging and phosphatic rock dosage in the part of " embodiment " below.These combinations only provide in an exemplary fashion, and should not be considered to limit the scope of the invention.
Such as in the context of the explanation of background technology explanation, calcium oxide can exist with the by product of expectation technique (for example causticization) in bayer liquors, and/or can be added into to realize for example alumina stable when separating residual solid (red mud) from unprocessed solution of the result that expects.Therefore, it will be appreciated by those skilled in the art that the calcium oxide that is introduced in the bayer liquors as the by product of expecting technique can provide such as other process benefit of stablizing aluminum oxide during separating residual solid (red mud) from unprocessed solution.
In a kind of form of the present invention, method comprises the steps:
The dissolving aluminous ore is to be provided at the red mud slurry in the phosphatic unprocessed bayer liquors in caustic solution; Then
Add a certain amount of calcium oxide in the slurries of this red mud in phosphatic unprocessed bayer liquors and containing suspension in calcium oxide and the phosphatic unprocessed bayer liquors to produce red mud; Then
Separating red mud from this suspension; With
Unprocessed solution is contacted with a certain amount of phosphatic rock.
Thereby cause the precipitation of further phosphatic rock and reduce the concentration of calcium oxide in the unprocessed solution.
Separating red mud can occur simultaneously with the step that unprocessed solution is contacted with phosphatic rock from unprocessed solution.
In a kind of form of the present invention, the step of separating red mud comprises the flow through step of strainer of the suspension of red mud in unprocessed solution from unprocessed solution, with the step that occurs before the step of the strainer of flowing through in the suspension in the unprocessed solution of red mud and this will this unprocessed solution to contact with a certain amount of phosphatic rock.
In the preferred form of the present invention, the step of separating red mud comprises the steps: from unprocessed solution
The slurry stream of red mud and unprocessed solution through one or more sand-settling devices, is produced the second slurries of red mud and unprocessed solution, and these second slurries contain the red mud of lower ratio with respect to unprocessed solution;
Through one or more thickners, generation is the thickener underflow of red mud basically and is the thickner overflow of unprocessed solution basically with this second slurry stream; With
Make the thickner overflow strainer of flowing through.
In this form of the present invention, the step of a certain amount of calcium oxide being added in the suspension of red mud and unprocessed solution is to occur before the step of strainer that the thickner overflow is flowed through.
When adding calcium oxide for the purpose of stablizing aluminum oxide, can with the slurry stream of red mud and unprocessed solution through one or more sand-settling devices, produce and to occur after the step of the second slurries of red mud and unprocessed solution to add a certain amount of calcium oxide in the suspension of red mud and unprocessed solution step, described the second slurries contain the red mud that hangs down ratio.
In addition, when adding calcium oxide for the purpose of stablizing aluminum oxide, can with the second slurry stream through one or more thickners, produce and to be the thickener underflow of red mud basically and to be that step in the suspension of red mud and unprocessed solution is added a certain amount of calcium oxide in generation after the thickner overflow step of unprocessed solution basically.
In a kind of form of the present invention, strainer is fixed-bed type strainer, for example sand-bed filter.It will be apparent for a person skilled in the art that the fixed-bed type strainer has utilized one to be the bed that the filtration medium of inertia forms at least basically, it is supported by screen cloth, solution this screen cloth of will flowing through.Use sand-bed filter as an example, casting bed is supported by metallic sieve, along with bayer liquors is pumped into bed upward or enters (normally by rotating the hole in the water jet standpipe) in the bed, and the gap in the bed of flowing through under gravity, the red mud particle in the feed bayer liquors is blocked in the sand grain surface on this.
When strainer is the fixed-bed type strainer, with unprocessed bayer liquors and the contact of a certain amount of phosphatic rock and make the flow through step of strainer of thickner overflow comprise the strainer of then this binding substances being flowed through is combined in the thickner overflow with a certain amount of phosphatic rock.
The common cyclical operation of fixed-bed type strainer: final, abundant granular material is being that the accumulation of inertia filtration medium is almost completely to have reduced the effectiveness of strainer basically.At this moment, usually by backwashing to upgrade strainer.Time between strainer upgrades is commonly referred to as a filtration cycle.
As discussed above, a series of factor is depended in the reduction of calcium oxide concentration, comprises residence time.In the preferred form of the present invention, thereby control these factors realize the calcium oxide concentration of expectation within being less than or equal to the residence time of single filtration cycle reduction.In this case, suppose constant feed condition, the decline of the calcium oxide that occurs by the circulation of each strainer at any given time should with until this time point to strainer to proportional with the total mass of phosphatic rock.
In a kind of form of the present invention, strainer is cake formula strainer.It will be apparent for a person skilled in the art that; cake formula strainer is such strainer; it is (thin but be easy to be filtered with the flocculating aids solid; chemically inert granulating solid) is pumped in the strainer to use strainer filter cake precoat filter liquid plate (by the sieve structure of grid cloth strainer cloth covering); it allows solution stream through its pore structure when pumping into unprocessed solution by strainer; but hold back the mud solid, selectively under gravity or the vacuum but usually (filter) under pressure (as at the Kelly strainer) for unprocessed bayer liquor and carry out.
The flocculating aids solid can be pumped to strainer in following any one or two kinds of modes:
(i) before main filtration stream, to form initially without mud strainer cake layer at the strainer impeller; And/or
(ii) be mixed in the strainer feed solution, produce by easy stages the strainer cake layer of holding back mud to run through each unprocessed bayer liquor filtration cycle.
In a kind of form of the present invention, when strainer is cake formula strainer, unprocessed solution is comprised step with the step that contacts of a certain amount of phosphatic rock:
Add a certain amount of phosphatic rock to the thickner overflow.
In a kind of form of the present invention, when strainer was cake formula strainer, the step of separating red mud comprised the steps: from unprocessed solution
The thickner overflow is mixed with a certain amount of flocculating aids; With
With the thickner overflow strainer of flowing through.
When the present invention includes the thickner overflow with step that a certain amount of flocculating aids mixes, the method can be included in the additional step before this step:
A certain amount of phosphatic rock is mixed with a certain amount of flocculating aids;
So that the step impact that thickner overflow and a certain amount of flocculating aids are mixed contacts unprocessed solution with a certain amount of phosphatic rock step.
In a kind of form of the present invention, when strainer was cake formula strainer, the step of separating red mud comprised the steps: from unprocessed solution
To cake formula filter application flocculating aids layer; Then
With thickner overflow flow through flocculating aids layer and strainer.
When the step that the present invention includes to filter application flocculating aids layer, the method can be included in the additional step before this step:
A certain amount of phosphatic rock and a certain amount of flocculating aids are mixed to form a flocculating aids layer;
So that with the thickner overflow step impact of flocculating aids layer and strainer contacts unprocessed solution with a certain amount of phosphatic rock the step of flowing through.
In a kind of form of the present invention, when strainer is cake formula strainer, the step of red mud from unprocessed solution separating comprised the steps:
The slurry stream of red mud and unprocessed solution through one or more sand-settling devices, is produced the second slurries of red mud and unprocessed solution, and these second slurries contain the red mud of lower ratio with respect to unprocessed solution;
Through one or more thickners, generation is the thickener underflow of red mud basically and is the thickner overflow of unprocessed solution basically with this second slurry stream;
The phosphatic rock of the first amount is mixed to produce the first mixture with the flocculating aids of the first amount;
The first mixture layer is applied to strainer;
The phosphatic rock that the flocculating aids and second of the second amount is measured mix to produce the second mixture;
The second mixture is mixed with the thickner overflow; Then
With thickner overflow flow through the first mixture layer and strainer;
In order to the second mixture and thickner overflow mixed and flow through per step of step of the first mixture layer and strainer of thickner overflow all affected the step that unprocessed solution is contacted with a certain amount of phosphatic rock.
Preferably, the granularity of phosphatic rock and flocculating aids is similar.That is to say the risk that thinless remarkable phosphatic rock to causing filtrate pollutes and not have slightly to remove the required surface-area of calcium oxide of enough ratios to losing.The phosphatic rock that mainly drops on 5-15 micron granularity scope will satisfy this two standards.Perhaps, and as discussed above, can use the larger particle diameter of the surface-area with increase.
Usually can be at many Bayer process refinery situ production phosphatic rock, this gives and the invention provides extra advantage.
For example, can prepare phosphatic rock by interpolation lime source and phosphate source in bayer liquors.In a kind of form of the present invention, the lime source provides with the form of white lime, tricalcium aluminate or filter pressing sludge.Phosphate source and bayer liquors can high phosphate Bayer process waste liquid form provide together.In about 90 ℃ temperature, very short for the preparation of the residence time of phosphatic rock, about 15-30min.The phosphatic rock of so producing can be separated from residual solution before being used for method of the present invention.Perhaps, the slurries of phosphatic rock and upper solution can be used for method of the present invention.
International patent application (PCT/AU2006/000140) (Alcoa of Australia Limited) thus described in bayer liquors by adding phosphate source causticization phosphoric acid salt and controlled the precipitation that this phosphoric acid salt impels the calcium phosphate precipitation thing, in a kind of form of the present invention, this throw out is phosphatic rock.The cost of phosphate source is obviously depended in the practical application of these methods.Therefore method of the present invention promotes causticization phosphoric acid salt and this phosphatic method of control in the bayer liquors of (PCT/AU2006/000140) slightly by using so elementary by product.
Therefore, according to the present invention, provide a kind of method for the treatment of containing calcium oxide and phosphatic unprocessed bayer liquors, the method comprises the steps:
Add phosphate source to containing in calcium oxide and the phosphatic bayer liquors;
Contain interpolation caustic alkali reagent in calcium oxide and the phosphatic bayer liquors to this; With
Form with a certain amount of phosphatic rock forms the calcium phosphate precipitation thing;
Thereby make this contain calcium oxide and phosphatic bayer liquors causticization; Then
This bayer liquors is contacted with at least a portion of a certain amount of phosphatic rock; With
Thereby cause further phosphatic rock precipitation and reduce the calcium oxide concentration that this contains calcium oxide and phosphatic bayer liquors.
As used herein, term " phosphate source " will be used to include but not limited to provide any form of the phosphorus of orthophosphoric acid salt negatively charged ion in bayer liquors.
Valuably, method of the present invention allows the bayer liquors causticization and controls simultaneously phosphoric acid salt and calcium concn in this solution.
Description of drawings
Below with reference to two kinds of embodiments and accompanying drawing, only describe in the mode of example and carry out optimal mode of the present invention, wherein:
Fig. 1 is schematically illustrating of Bayer process, wherein uses cake formula strainer separating residual solid (red mud) from unprocessed bayer liquor, and it shows the first embodiment of the present invention;
Fig. 2 is schematically illustrating of Bayer process, wherein uses cake formula strainer separating residual solid (red mud) from unprocessed bayer liquor, and it shows the second embodiment of the present invention;
Fig. 3 illustrates the residence time of hydroxylapatite carbonate to the chart of calcium oxide concentration as influencing factor;
Fig. 4 illustrates hydroxylapatite carbonate and flocculating aids concentration to the chart of calcium oxide concentration as influencing factor;
Fig. 5 is illustrated in the continuous cake formula filtration process hydroxylapatite carbonate to the graphic representation of calcium oxide concentration as influencing factor; With
Fig. 6 illustrates hydroxylapatite carbonate and flocculating aids to the graphic representation of calcium oxide concentration as influencing factor;
Fig. 7 shows the result from series of experiments, wherein preparation hydroxylapatite carbonate in containing the excessive phosphatic solution of stoichiometry;
Fig. 8 shows the result from series of experiments, and its explanation phosphatic rock wears out on the impact of the effectiveness of removing calcium oxide; With
Fig. 9 has compared the fresh phosphatic rock of recovery and the amount of 1 day age and freshly prepd phosphatic rock calcium oxide of removing from solution used.
Yet, this description should be interpreted as the present invention's general introduction that limits by any way the front.
Embodiment
With reference to figure 1, the reduction of use the first embodiment contains the method for the calcium oxide concentration in calcium oxide and the phosphatic unprocessed bayer liquors in Bayer process, wherein, salic ore is dissolved in the caustic solution 10, the slurries 12 of red mud in phosphatic unprocessed solution are provided.Then make the slurry stream of this red mud in phosphatic unprocessed solution through thickner 14, generation is the thickener underflow 16 of red mud basically and is the thickner overflow 18 of unprocessed bayer liquor basically.
Except phosphoric acid salt, thickner overflow 18 also contains calcium oxide.This calcium oxide can be derived from many possible sources any or multiple.For example, by add from the high-enriched organics solution, as lime or the calcite (for example during the technique of solution causticization) of the by product of other Bayer process, and/or by the interpolation calcium oxide of having a mind in order to stablize aluminum oxide.
Use the method for the first embodiment in Bayer process, it utilizes cake formula strainer 20.A certain amount of Ca
7Na
2(CO
3)
3(PO
4)
3(H
2O)
3(OH) flocculating aids 24 of the phosphatic rock carbonate 22 of form and the first amount is in conjunction with then being applied to cake formula strainer 20 as layer to form precoating 26.The flocculating aids 28 of the second amount mixes to form the slurries 30 of flocculating aids and thickner overflow with thickener underflow 18.
The amount that is applied to the phosphatic rock carbonate 22 of cake formula strainer 20 depends on a series of factor, wherein considerable is the reduction (with the speed that reduces) of the calcium oxide concentration of expectation, such as in the general introduction of the present invention in front discussion, measure larger cause reduction more/faster.In addition, and also discuss in front the general introduction of the present invention, the characteristic of phosphatic rock carbonate 22 (for example particle diameter and surface-area) impact realizes that in preset time given calcium oxide concentration reduces required amount.In addition, and also discuss in front the general introduction of the present invention, the characteristic of thickener underflow 18 (for example calcium oxide concentration, phosphate concn and temperature) impact realizes that in preset time given calcium oxide concentration reduces required amount.
Can change the impact that these parameters produce the method for this embodiment with the factor of other relevant Bayer process with balance.There is not a cover optimum parameter.Yet common expectation is chosen in the interior parameter combination that realizes the calcium oxide minimizing of expectation of setting-up time of a filtration cycle.
Although a certain amount of phosphatic rock carbonate 22 can be derived from any source, easily, this a certain amount of phosphatic rock carbonate 22 is as the by product of another Bayer process step and produce.
Then the cake formula strainer 20 of slurries 30 being flowed through contacts thereby make the unprocessed bayer liquor that exists with thickner overflow 18 forms in the slurries 30 and be applied to a certain amount of phosphatic rock carbonate 22 that exists in the layer of cake formula strainer 20.This causes the calcium oxide concentration in further phosphatic rock precipitation and the reduction bayer liquors.
With reference now to Fig. 2,, with the substantially similar Bayer process of the Bayer process of the method for using the first embodiment in use the method that the calcium oxide concentration that contains calcium oxide and phosphatic unprocessed bayer liquors of the second embodiment reduces, and will use the identical parts of identical numeral.Yet the Bayer process of using the method for the second embodiment uses fixed bed filtering device 32 to replace cake formula strainer.
The amount of the phosphatic rock calcium carbonate 34 that mixes with thickner overflow 18 depends on a series of factor, wherein considerable is the reduction (with the speed that reduces) of the calcium oxide concentration of expectation, such as in the general introduction of the present invention in front discussion, measure the larger more/faster reduction that causes.In addition, and also discuss in front the general introduction of the present invention, the characteristic of phosphatic rock carbonate 34 (for example particle diameter and surface-area) impact realizes that in preset time given calcium oxide concentration reduces required amount.In addition, and also discuss in front the general introduction of the present invention, the characteristic of thickener underflow 18 (for example calcium oxide concentration, phosphate concn and temperature) impact realizes that in preset time given calcium oxide concentration reduces required amount.
Can change the impact that these parameters produce the method for this embodiment with the factor of other relevant Bayer process with balance.There is not a cover optimum parameter.
Result and embodiment
Embodiment 1
Table 1 and Fig. 3 show with hydroxylapatite carbonate-Ca
7Na
2(CO
3)
3(PO
4)
3(H
2O)
3(OH)-and the result of the series of experiments that carries out, illustrate that phosphatic rock is in the effectiveness of the calcium oxide of removing dissolving from bayer liquors.
To contain 80,160 and 250ppm phosphoric acid salt (be expressed as P
2O
5) unprocessed solution to be heated to temperature be 95 ℃.Dosage with 0.2g phosphatic rock/L or 1g phosphatic rock/L adds hydroxylapatite carbonate in solution.This mixture is mixed 1min or 10min under this temperature.
The data presentation that table 1 provides and hydroxylapatite carbonate contact the concentration that reduces calcium oxide in the solution.The reduction degree of calcium oxide concentration depends on phosphatic concentration in dosage, retention time and the solution in the solution.
Table 1
| ppm P 2O 5 | Be in 95 ℃ time | Phosphatic rock dosage (g/L) | CaO descend (mg/L) |
| 80 | 1min | 1 | 16.1 |
| 160 | 1min | 1 | 17.2 |
| 250 | 1min | 1 | 20.4 |
| 80 | 10min | 1 | 21.3 |
| 160 | 10min | 1 | 21.5 |
| 250 | 10min | 1 | 21.8 |
| 80 | 10min | 0.2 | 11.1 |
| 160 | 10min | 0.2 | 16.4 |
| 250 | 10min | 0.2 | 16.6 |
Table 2 and Fig. 4 have shown the result of series of experiments, and wherein hydroxylapatite carbonate mixes with tricalcium aluminate (TCA) with proof in the presence of flocculating aids, and phosphatic rock is removed the effectiveness of the calcium oxide of dissolving from bayer liquors.
Pure unprocessed solution and the unprocessed solution that contains 0.5g TCA/L are heated to 95 ℃ temperature.Dosage with 0.2g phosphatic rock/L or 1g phosphatic rock/L adds hydroxylapatite carbonate in solution.This mixture is mixed 1min or 10min under this temperature.
The data presentation that table 2 provides has reduced the concentration of calcium oxide in the solution with contacting of hydroxylapatite carbonate in the presence of flocculating aids.The reduction degree of calcium oxide concentration still depends on dosage and retention time in the solution.
Table 2
| Be in 95 ℃ time | Phosphatic rock dosage (g/L) | TCA dosage (g/L) | CaO descend (mg/L) |
| 0 | 0 | 0 | 13.1 |
| 1min | 0.2 | 0 | 20.2 |
| 1min | 1 | 0 | 16.9 |
| 10min | 0.2 | 0 | 23.8 |
| 10min | 1 | 0 | 11.9 |
| 1min | 0.2 | 0.5 | 20.6 |
| 1min | 1 | 0.5 | 17.5 |
| 10min | 0.2 | 0.5 | 24.8 |
| 10min | 1 | 0.5 | 13.1 |
Embodiment 3
Table 3 and Fig. 5 have shown the result of lab scale experiment, and wherein hydroxylapatite carbonate mixes the effectiveness to prove that phosphatic rock is removed the calcium oxide of dissolving from bayer liquors in continuous cake formula filtration process with tricalcium aluminate (TCA) as flocculating aids.
The dosage of 500g hydroxylapatite carbonate with 0.04g phosphatic rock/g TGA is joined in the tricalcium aluminate slurries.The flocculating aids slurries are joined in the unprocessed solution and surpass about 6h the time chien shih mixture flow through the Kelly strainer.
The data presentation that table 3 provides when hydroxylapatite carbonate in the strainer filter cake with after flocculating aids mixes, it has reduced the concentration of the calcium oxide in the solution.The reduction degree of calcium oxide concentration is along with the increase of the thickness of cake and the therefore increase of the amount of hydroxylapatite carbonate and improving in the strainer filter cake.
Table 3
| Line duration (h:mm) | CaO descend (mg/L) |
| 0:00 | 5.1 |
| 0:15 | 4.0 |
| 0:45 | 4.5 |
| 1:15 | 5.9 |
| 2:15 | 7.0 |
| 2:45 | 7.1 |
| 3:15 | 8.3 |
| 3:45 | 9.1 |
| 4:15 | 9.0 |
| 4:45 | 8.8 |
| 5:15 | 10.3 |
| 5:45 | 11.5 |
Embodiment 4
Table 4 and Fig. 6 have shown the result of lab scale experiment, and wherein hydroxylapatite carbonate mixes with tricalcium aluminate (TCA) and is applied to filter media as pre-filtering coating (precoated layer).
The dosage of 500g hydroxylapatite carbonate with 0.27g phosphatic rock/g TGA is joined in the tricalcium aluminate slurries.Before solution filter, this mixture is applied to the cloth film of kelly strainer as coating.To there be the other flocculating aids slurries of hydroxylapatite carbonate to add unprocessed solution.Surpass 5h the time chien shih mixture flow through Kelly strainer and phosphatic rock/TCA coating.
The data presentation that table 4 provides is after hydroxylapatite carbonate mixes with flocculating aids and uses as precoated layer, and it has reduced the concentration of the calcium oxide in the solution.When the semi-invariant of phosphatic rock in the strainer filter cake equaled amount in the precoated layer at current embodiment, the reduction degree of calcium oxide concentration was comparable to the last degree that realizes of experiment of embodiment 3 always in the whole experiment.
Table 4
| Line duration (h:mm) | CaO descend (mg/L) |
| 2:30 | 12.0 |
| 3:00 | 13.6 |
| 3:30 | 13.6 |
| 4:00 | 13.8 |
| 4:30 | 14.4 |
| 5:00 | 14.7 |
Embodiment 5: preparation excessive phosphoric acid salt during phosphatic rock
Fig. 7 has shown the result of series of experiments, and wherein preparation hydroxylapatite carbonate is being removed aspect the calcium oxide improving the impact of phosphatic rock activity with proof excess phosphoric acid salt in containing the excessive phosphate solution of stoichiometry.
With Na
3PO
4.12H
2O is dissolved in the part of pure waste liquid and this solution is heated to 90 ℃ temperature.White lime is added in the solution, with stoichiometry or molar ratio computing, so that the phosphate concn in the solution is stoichiometry excessive 50% or 100% with respect to stoichiometric hydroxylapatite carbonate.Mixture was reacted 15 minutes under this temperature, then utilize to filter with washing the phosphatic rock sample is separated from solution.
To contain the 50ppm phosphoric acid salt of having an appointment and (be expressed as P
2O
5) pure unprocessed solution be heated to 95 ℃ temperature.The hydroxylapatite carbonate of preparation is joined in the solution with the dosage of about 1g phosphatic rock/L.Make mixture under this temperature, mix 10min.
The effectiveness that digital proof shown in Fig. 7 uses the hydroxylapatite carbonate that contains in the phosphatic solution of lower concentration to remove calcium oxide can improve by preparation hydroxylapatite carbonate in the solution that contains excess phosphoric acid salt.This effect is proportional with the percentage ratio for preparing excess phosphoric acid salt in the solution.
Embodiment 6: aging phosphatic rock and new phosphatic rock
Fig. 8 has shown the result of series of experiments, and it has proved the aging impact on the effectiveness of removing calcium oxide of phosphatic rock.
Ortho-phosphoric acid is joined pure waste liquid and this solution is heated to 90 ℃ temperature.Stoichiometry with respect to the metering of hydroxylapatite carbonate chemistry joins solution with white lime.Mixture was reacted 15 minutes under this temperature, then utilize to filter with washing the phosphatic rock sample is separated from solution.Near the wet cake of half in room temperature storage 24h.
To contain the 40-60ppm phosphoric acid salt of having an appointment and (be expressed as P
2O
5) pure unprocessed solution be heated to 95 ℃ temperature.With freshly prepd hydroxylapatite carbonate samples with about 0.2,0.3 and the dosage of 1g phosphatic rock/L add solution.Make mixture under this temperature, react 10min.Use the wet phosphatic rock that stores behind 24h, to repeat this experiment.
It is proportional that the data presentation of Fig. 8 uses new phosphatic rock to remove the dosage of calcium oxide and used phosphatic rock, or even in containing the phosphatic solution of lower concentration.On the contrary, no matter what dosage phosphatic rock is, the concentration of the calcium oxide of being removed from solution by " aging " phosphatic rock can be ignored, and proves that phosphatic rock loses its " activity " between the shelf lives.
Embodiment 7: the phosphatic rock of reactivate
Fig. 9 shows the result of series of experiments, and the phosphatic rock that its proof is aging is removed the ability of calcium oxide and can be regenerated by soak phosphatic rock in the solution that contains excess phosphoric acid salt.
With Na
3PO
4.12H
2O is dissolved in the part of pure waste liquid and solution is heated to 90 ℃ temperature.Hydroxylapatite carbonate is joined in the solution with such molar ratio, so that the phosphate concn in solution is that 100% stoichiometry is excessive with respect to the stoichiometry of hydroxylapatite carbonate.Mixture was reacted 15 minutes under this temperature, then utilize to filter with washing the phosphatic rock sample is separated from solution.
To contain 40-50ppm phosphoric acid salt and (be expressed as P
2O
5) pure unprocessed solution be heated to 95 ℃ temperature." recovering fresh " hydroxylapatite carbonate samples is joined solution with the dosage of about 1g phosphatic rock/L.Make mixture under this temperature, mix 10min.
The amount that Fig. 9 has compared that use " recovers fresh " phosphatic rock and 1 day age and freshly prepd phosphatic rock are removed calcium oxide from solution.Data shown in Fig. 9 show that the activity of aging phosphatic rock can be regenerated by soak hydroxylapatite carbonate in the solution that contains excess phosphoric acid salt for removing calcium oxide.
Embodiment 1-7 clearly proves the effectiveness of the calcium oxide concentration of method of the present invention in reducing bayer liquors.
Apparent change and variation are considered to fall within the scope of the present invention for those skilled in the art.
Claims (24)
1. a reduction contains the method for calcium oxide concentration in calcium oxide and the phosphatic unprocessed bayer liquors, and described method comprises the steps:
This is contained calcium oxide contacts with a certain amount of phosphatic rock with phosphatic unprocessed bayer liquors;
Thereby cause further phosphatic rock precipitation and reduce this and contain calcium oxide concentration in calcium oxide and the phosphatic unprocessed bayer liquors.
2. method according to claim 1 is characterized in that, described calcium oxide and the phosphatic unprocessed bayer liquors of containing is by following step production:
The salic ore of dissolving is to provide the slurries of red mud in phosphatic unprocessed bayer liquors in caustic solution; Then
Add a certain amount of calcium oxide in the slurries of described red mud in phosphatic unprocessed bayer liquors and containing suspension in calcium oxide and the phosphatic unprocessed bayer liquors to produce red mud; Then
Separating red mud contains calcium oxide and phosphatic unprocessed bayer liquors with production from this suspension.
3. method according to claim 2 is characterized in that, the step of separating red mud comprises red mud in the flow through step of strainer of the described suspension that contains in calcium oxide and the phosphatic unprocessed bayer liquors from described suspension.
4. method according to claim 2 is characterized in that, the step of separating red mud comprises the steps: from described suspension
With the slurry stream of red mud and phosphatic unprocessed bayer liquors through one or more sand-settling devices, produce the second slurries of red mud and phosphatic unprocessed bayer liquors, described the second slurries contain the red mud with respect to the lower ratio of phosphatic unprocessed bayer liquors;
Through one or more thickners, generation is the thickener underflow of red mud basically and is the thickner overflow of phosphatic unprocessed bayer liquors basically with described the second slurry stream; With
Make the thickner overflow strainer of flowing through;
Wherein said step of adding a certain amount of calcium oxide in the slurries of red mud in phosphatic unprocessed bayer liquors flows through the thickner overflow to occur before the step of strainer described.
5. method according to claim 4, it is characterized in that, add described calcium oxide for the purpose of stablizing aluminum oxide, and adding a certain amount of calcium oxide in the slurries of red mud in phosphatic unprocessed bayer liquors step is to occur in after described slurry stream with red mud and phosphatic unprocessed bayer liquors produces red mud and phosphatic unprocessed bayer liquors through one or more sand-settling devices the step of the second slurries, and described the second slurries contain the red mud of low ratio.
6. method according to claim 4, it is characterized in that, add described calcium oxide for the purpose of stablizing aluminum oxide, and to add a certain amount of calcium oxide in the slurries of red mud in phosphatic unprocessed bayer liquors step be to occur in described the second slurry stream produced through one or more thickners to be the thickener underflow of red mud basically and to be after the step of thickner overflow of phosphatic unprocessed bayer liquors basically.
7. method according to claim 4, it is characterized in that, described strainer is the fixed-bed type strainer, and the described calcium oxide that will contain contacts with a certain amount of phosphatic rock with phosphatic unprocessed bayer liquors and makes the flow through step of strainer of thickner overflow comprise and described thickner overflow is combined the strainer of then described binding substances being flowed through with a certain amount of phosphatic rock.
8. method according to claim 3 is characterized in that, described strainer is cake formula strainer.
9. method according to claim 4 is characterized in that, the described calcium oxide that will contain comprises step with phosphatic unprocessed bayer liquors with the step that a certain amount of phosphatic rock contacts:
In the thickner overflow, add a certain amount of phosphatic rock.
10. method according to claim 4 is characterized in that, described from suspension the step of separating red mud comprise the steps:
The thickner overflow is mixed with a certain amount of flocculating aids; With
With the described thickner overflow strainer of flowing through.
11. method according to claim 10 is characterized in that, with before thickner overflow and the step that a certain amount of flocculating aids mixes, described method comprises step:
A certain amount of phosphatic rock is mixed with a certain amount of flocculating aids;
So that the step impact that thickner overflow and a certain amount of flocculating aids are mixed will contain the step that calcium oxide and phosphatic unprocessed bayer liquors contact with a certain amount of phosphatic rock.
12. method according to claim 4 is characterized in that, the step of separating red mud comprises the steps: from suspension
A certain amount of phosphatic rock and a certain amount of flocculating aids are mixed to form a flocculating aids layer;
To this flocculating aids layer of cake formula filter application; Then
With thickner overflow flow through flocculating aids layer and strainer;
In order to the flow through step impact of flocculating aids layer and strainer of thickner overflow will be contained the step that calcium oxide and phosphatic unprocessed bayer liquors contact with a certain amount of phosphatic rock.
13. method according to claim 4 is characterized in that, described from suspension the step of separating red mud comprise the steps:
With the slurry stream of red mud and phosphatic unprocessed bayer liquors through one or more sand-settling devices, produce the second slurries of red mud and phosphatic unprocessed bayer liquors, described the second slurries contain the red mud with respect to the lower ratio of phosphatic unprocessed bayer liquors;
Through one or more thickners, generation is the thickener underflow of red mud basically and is the thickner overflow of phosphatic unprocessed bayer liquors basically with described the second slurry stream;
The phosphatic rock of the first amount is mixed to produce the first mixture with the flocculating aids of the first amount;
The first mixture layer is applied to cake formula strainer;
The phosphatic rock that the flocculating aids and second of the second amount is measured mix to produce the second mixture;
The second mixture is mixed with the thickner overflow; Then
With thickner overflow flow through the first mixture layer and cake formula strainer;
In order to the second mixture and thickner overflow mixed and flow through per step of step of the first mixture layer and strainer of thickner overflow all affected and describedly will contain the step that calcium oxide and phosphatic unprocessed bayer liquors contact with a certain amount of phosphatic rock.
14. a processing contains the method for calcium oxide and phosphatic unprocessed bayer liquors, described method comprises the steps:
Add phosphate source to containing in calcium oxide and the phosphatic unprocessed bayer liquors;
Contain interpolation caustic alkali reagent in calcium oxide and the phosphatic unprocessed bayer liquors to this; With
Form with a certain amount of phosphatic rock forms the calcium phosphate precipitation thing;
Thereby make described contain calcium oxide and phosphatic unprocessed bayer liquors causticization; Then
The described calcium oxide that contains is contacted with at least a portion of a certain amount of phosphatic rock with phosphatic unprocessed bayer liquors; With
Thereby cause further phosphatic rock precipitation and reduce the described calcium oxide concentration that contains calcium oxide and phosphatic unprocessed bayer liquors.
15. according to claim 1 or 14 described methods, it is characterized in that described phosphatic rock has general formula A
10(XO
4)
6(OH, F, Cl)
2.nH
2O, wherein: A is selected from Ba, Ca, Ce, K, Na, Pb, Sr, Y; X is selected from As, P, Si, V; With when X is selected from P, PO
4Can be by CO
3Replace.
16. method according to claim 15 is characterized in that, described A is that Ca and Na and described phosphatic rock are at least mainly to have general formula Ca
10-xNa
2x/3(PO
4)
6-x(CO
3)
x(OH)
2-x/3.xH
2O, wherein, the hydroxylapatite carbonate of 0≤x≤3, or be provided with any mixture of this compound.
17. method according to claim 15 is characterized in that, described phosphatic rock is with Ca
7Na
2(CO
3)
3(PO
4)
3(H
2O)
3(OH) form is provided.
18. according to claim 1 or 14 described methods, it is characterized in that described phosphatic rock is by the excessive phosphoric acid salt preparation of stoichiometry.
19. according to claim 1 or 14 described methods, it is characterized in that described phosphatic rock is new precipitation.
20. according to claim 1 or 14 described methods, it is characterized in that the amount of described phosphatic rock is 200-300g in every kL bayer liquors.
21. according to claim 1 or 14 described methods, it is characterized in that, the phosphatic concentration of described bayer liquors be between about 40 and 400ppm between.
22. according to claim 1 or 14 described methods, it is characterized in that, the temperature in the described bayer liquors be about 70 ℃ and more than.
23. method according to claim 22 is characterized in that, the temperature in the described bayer liquors is between 100 ℃ and 105 ℃.
24. according to claim 1 or 14 described methods, it is characterized in that described a certain amount of phosphatic rock comprises the phosphatic rock with high surface area/volume ratio example.
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|---|---|---|---|
| AU2006901815 | 2006-04-07 | ||
| AU2006901815A AU2006901815A0 (en) | 2006-04-07 | Method of Reducing Calcia Concentrations of Green Bayer Process Liquors | |
| PCT/AU2007/000460 WO2007115365A1 (en) | 2006-04-07 | 2007-04-05 | Method of reducing calcia concentrations of green bayer process liquors |
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| CN (1) | CN101437758B (en) |
| AU (1) | AU2007236547B2 (en) |
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| CN101264910B (en) * | 2008-04-25 | 2010-10-13 | 河南未来铝业（集团）有限公司 | Mother liquor evaporation seed addition method for aluminum hydroxide or aluminum oxide production technique by Bayer process |
| FR2934852B1 (en) * | 2008-08-06 | 2011-06-24 | Alcan Int Ltd | IMPROVEMENT TO THE BAYER PROCESS FOR PRODUCTION OF ALUMINA TRIHYDRATE, SAID PROCESS COMPRISING A STEP IN WHICH THE SURSATURATED LIQUEUR IS FILTERED AT HIGH TEMPERATURE BEFORE DECOMPOSITION |
| KR20140057592A (en) * | 2011-08-08 | 2014-05-13 | 바스프 에스이 | Method for producing ultrapure aluminum oxide by cleaning clay |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4016238A (en) * | 1975-08-29 | 1977-04-05 | Urbina Davalos Fernando | Process for the obtention of alumina and phosphate values by the alkaline decomposition of silica-containing aluminum phosphate ores |
| US4758412A (en) * | 1985-11-08 | 1988-07-19 | Rhone-Poulenc Specialites Chimiques | Production of rare earth hydroxides from phosphate ores |
| US5534235A (en) * | 1995-09-05 | 1996-07-09 | Nalco Chemical Company | Polymers containing phosphonic acid groups for the treatment of red mud in the Bayer process |
| CN1377829A (en) * | 2002-03-05 | 2002-11-06 | 平顶山市汇源化学工业公司 | Process for removing organics from sodium Bayer process aluminate solution |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU814866A1 (en) * | 1979-05-07 | 1981-03-23 | Всесоюзный Научно-Исследовательскийи Проектный Институт Алюминиевой,Магниевой И Электродной Промышленности | Method of processing sulfide-sulfate mixture |
| HU187654B (en) * | 1982-02-26 | 1986-02-28 | Ajkai Timfoeldgyar Aluminium | Process for reduction of damages in production of aluminium oxid of bayer system |
| JPS59156489A (en) * | 1983-02-28 | 1984-09-05 | Kurita Water Ind Ltd | Phosphate-contg. water disposal |
| RU2188794C1 (en) * | 2001-03-28 | 2002-09-10 | Государственное унитарное предприятие Уральский научно-исследовательский химический институт с опытным заводом | Method of processing soda-sulfate mixture |
| WO2006081626A1 (en) * | 2005-02-03 | 2006-08-10 | Alcoa Of Australia Limited | Method for the causticisation of bayer process solutions |
-
2007
- 2007-04-05 WO PCT/AU2007/000460 patent/WO2007115365A1/en active Application Filing
- 2007-04-05 RU RU2008143330/05A patent/RU2445264C2/en not_active IP Right Cessation
- 2007-04-05 CN CN200780016077.6A patent/CN101437758B/en active Active
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4016238A (en) * | 1975-08-29 | 1977-04-05 | Urbina Davalos Fernando | Process for the obtention of alumina and phosphate values by the alkaline decomposition of silica-containing aluminum phosphate ores |
| US4758412A (en) * | 1985-11-08 | 1988-07-19 | Rhone-Poulenc Specialites Chimiques | Production of rare earth hydroxides from phosphate ores |
| US5534235A (en) * | 1995-09-05 | 1996-07-09 | Nalco Chemical Company | Polymers containing phosphonic acid groups for the treatment of red mud in the Bayer process |
| CN1377829A (en) * | 2002-03-05 | 2002-11-06 | 平顶山市汇源化学工业公司 | Process for removing organics from sodium Bayer process aluminate solution |
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| AU2007236547B2 (en) | 2012-05-03 |
| RU2445264C2 (en) | 2012-03-20 |
| BRPI0709478A2 (en) | 2011-07-19 |
| WO2007115365A1 (en) | 2007-10-18 |
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