DE2429428A1 - Floating non-sulphidic copper ores - with addn of alkyl- or alkyl hydroxyalkyl celluloses as pushers for sludge-forming minerals - Google Patents

Abstract

Flotation of non-sulphide Cu ores, contg. predominantly oxidic components with standard collector-, frothing-and activating reagents, takes place by using, as passivating agents or pushers for talcum, clay and other sludge-forming minerals, alkyl- or alkyl hydroxyalkyl celluloses. In these cellulose ethers, (I), on av. 1-2 (1.4-1.6) of total 6 OH gps/glucose unit are etherified by 1-2C alkyl and/or 2-3C hydroxyalkyl gps. Pushing effect of (I) on gangues is selective.

Description

Flotation of non-sulphidic copper ores It is known to be valuable ore minerals to free them from undesired gait by means of flotation processes and thereby to enrich.

for this purpose, the finely ground raw ore is added with reagents, so-called collectors and frothers, suspended in water and air or inert gas passed through. Due to the hydrophobizing effect of the collector are selective the valuable ore particles are carried to the surface of the sludge with the air bubbles and held in the foam, from where they - as a concentrate - are removed. the worthless gait remains unchanged in the flotation pulp. Collectors and frothers must therefore act specifically on the ore particles to be separated, not against it on the under-desired gangue minerals. To further suppress the tendency the gangue minerals to float up together with the valuable minerals to be sorted out and to collect with them in the foam, it is known to use passivating agents, so-called Pusher to use.

These tools improve the separation e.g. by using the Prevent adsorption of the collector on the surface of the gangue minerals. Through this A flooding of the valuable minerals can have an oppressive effect even in the presence of worthless ones Very fine sludge, which is carried away mechanically into the foam and held in it be relieved.

The flotation of some non-sulphidic copper ores becomes special made more difficult by the fact that the breaking gait has a strong tendency to form fine sludge. Such a gait is impaired by its own easy floatability and high Adsorption of the flotation reagents makes the valuable minerals float out special measures required. To avoid these difficulties, such Ores previously desludged in a special process and then on their Valuable minerals are floated. It is also possible to use the sludge-forming minerals to separate first in a reverse flotation and then the metal-containing To win a share in another flotation tower. As with these elaborate However, losses of valuable mineral can occur is the two-step process single-stage flotation using reagents based on the sludge forming Gang act strongly depressing, because of the better yield of copper ore and because of prefer the simpler way of working. The pushers to be used here in GB-PS 1 320 350 Alginate is proposed, and sodium silicate is also often used used for this purpose (Ullmanns Encyclopadie der technischen Chemie 4th edition, Volume 2, page 120, Weinheim (1972)).

The pressing effect achieved in this way on the mud is improved however, the enrichment of non-sulphidic copper ores is only unsatisfactory. Other Compounds such as starch and dextrin (U.S. Patent 2,497,863, U.S. Patent 2,145,206) especially suitable as a printer for the flotation of fluorspar and precious metal ores.

The object of the present invention was therefore for the particularly difficult flotation of nictsulfidic copper ores with a high concentration of talc to find a suitable depressant reagent.

The cellulose derivatives previously known as pushers show at the Flotation of these ores had no effect and were therefore used as an aid to enrichment to exclude non-sulphidic copper ores from the outset. Such is an oppressive one Effect of cellulose glycolic acid etier, for example, only in the flotation of Hard coal known in the presence of fine sludge (DT-AS 1 002 702). Carboxymethyl cellulose is used as a trigger in the flotation of sulphidic nickel ores containing talc (Winnacker- Küchler "Chemical Technology", 3rd Edition, Volume 6, Page 65, Munich (1973)). Carboxymethyl cellulose, on the other hand, exhibits the accumulation talc-containing non-sulphidic Içup ter ores have no oppressive effect, as corresponding Experiments showed.

Surprisingly, it has now been found that nothing emulsifies during flotation Copper ores certain cellulose ethers have an excellent oppressive effect on talc and others muddy.

turn mineral. The invention thus relates to a method for the flotation of copper ores with predominantly oxidic fractions using Usual collector, foamer and act iv ierungsreagenzien, which is characterized is that as a trigger for talc, clay and other sludge-forming minerals, alkyl or alkyl hydroxyalkyl cellulose is used.

It is the cellulose ethers to be used according to the invention are those cellulose derivatives in which per glucose unit on average about 1 to 2, preferably 1.4 to 1.6 of the total of 6 hydroxyl groups by alkyl groups with 1 or 2 carbon atoms and / or by hydroxyalkyl groups with -2 or 3 Carbon atoms are etherified. It can thus both with the cellulose ethers to pure alkyl celluloses, especially methyl cellulose, as well as pure hydroxyalkyl celluloses, especially hydroxyethyl cellulose act. However, preference is given to alkyl hydroxyalkyl celluloses, in particular methyl hydroxyethyl cellulose, in which the proportion of Alkyl ether groups essentially predominate in the hydroxyalkyl ether groups. Preferably the proportion of hydroxyalkyl ether groups is about 10 to 30% of the number the alkyl ether groups.

The cellulose ethers to be used according to the invention can by action from alkyl chloride to alkalized cellulose and optionally additional or exclusive etherification with small amounts of alkylene oxide can be obtained. To the As already mentioned, the characterization of the cellulose ethers is, among other things, the average Degree of etherification or mean degree of substitution (DS), which is the average Indicates the number of alkoxyl groups on a glucose unit. In the invention to using alkyl hydroxyalkyl cellulose it is about 1 to 2, preferably 1.4 up to 1.6. The molecular weight of the cellulose ether is determined by the average degree of polymerization, i.e. the average number of glucose units per cellulose ether molecule, But instead of this, the characterization of the molecular size is given the easier - measurability in generalii the viscosity in 2% aqueous solution, measured according to Höppier at 200C. It amounts to according to the invention Cellulose ethers to be used about 20 to 4000 cP, cellulose derivatives with low values are preferred.

In the flotation of non-sulphidic copper ores according to the invention the usual collector, foamer and activation reagents are used. as suitable collectors are normally surface-active, anionic longer alkyl radicals containing substances used. It is known that they are among the anionic collectors Alkyl sulfonates and alkyl sulfates with 10 to 22 carbon atoms and saturated and unsaturated fatty acids having 10 to 22 carbon atoms and their alkali salts. Anionic thio compounds such as xanthates, in particular potassium amylxanthate; when using them, however, is a previous one Sulphidation of the non-sulphidic copper minerals with, for example, sodium sulphide or sodium hydrogen sulfide is necessary. In the flotation of non-sulphidic ores by means of Fatty acids as a collector can be used to brake the already without the addition of a jester occurring, excessive foaming additional nonionic substances, in particular saturated hydrocarbons. Otherwise, as a foamer known to use the following compounds: phenol homologous aliphatic alcohols, Terpene alcohols, alcohol polyglucol ethers, polypropylene glycols and polyalkoxy paraffins.

To carry out the method according to the invention, the talc-containing, non-sulphidic copper ore, e.g. pre-crushed in a jaw crusher and in a rod or ball mill, depending on the degree of flotation fineness wet or dry ~ grind. The flotation pulp becomes alkaline, preferably to pH Values in the range 8 to 11, set and the required Flotation reagents added in any order and in the usual amount. In general, the printer is checked first. The amount of according to the invention Cellulose ether to be used as a pusher can be varied within wide limits. In general About 100 to 2000 g cellulose ether / t ore are used. The invention Compounds can also be used together with known, suitable for non-sulfidic ores Pushers are used. After the reagents have been added, there is usually an exposure time from 1 to 15 minutes before the slurry is fed to the flotation cell will. The flotation takes place in a known manner with air being passed through.

In the following examples, an oxide with a high content of talc was used Copper ore from Xepublique dn Zaire, Shaba Province, floated. It contained 5.25% Cu (total), with 5.15% oxidic (4.9% malachite) bound; the talc content depends approx. 15% The ore was pre-crushed in the jaw crusher and in a laboratory ball mill ground to 60% smaller than 0.074 mm grain size.

The flotation was carried out in each case with refined samples of 1200 g in a 2.5-1 laboratory cell, Denver type, at a stirrer speed of 1700 revolutions / Minute. After the flotation apparatus had been started up, it was initially added by adding the pH of the pulp was adjusted to 9.6 by using sodium carbonate in a ten percent solution. The following reagents were used as gait pushers in the individual examples: 1. 480 mg Na2SiO3 2. 480 mg Na2SiO3 + 600 mg methyl hydroxyethyl cellulose (viscosity 21 - 26 cP according to Höppler) 3. 480 mg Na2SiO3 + 1200 mg methyl hydroxyethyl cellulose (Viscosity 21 - 26 cP according to Höppler) 4. 480 mg Na2SiO2 + 600 mg carboxymethyl cellulose (salt-free) 5. 480 mg Na2SiO3 + 1200 mg carboxymethyl cellulose (containing salt) First of all sodium silicate was added in each case. After an exposure time of 6 minutes was in Examples 2 to 5, the cellulose ether is metered in in one percent solution and more Conditioned for 3 minutes. Legs at one temperature An emulsion of hydrolyzed palm oil and gas oil kept at 450C in a ratio of up to 3: 1 subsequently became the preferred Samrnler or foamer reagent in a quantity of 1200 g / t was added and conditioned for a further minute.

The flotation lasted a total of 6 minutes in all examples, with three concentrates each (a, b and c) removed at intervals of 1, 2 and 3 minutes These three concentrates and the solids remaining in the flotation cell were called "mountains", were each dried, weighed and analyzed for copper. the The values obtained are compiled in the following table.

All percentages relate to weight.

TABLE Product% by weight Cu content Cu output% Sa.% Example 1 concentrate a 9.26 14.00 24.77 24.77 concentrate b 12.35 13.50 31.88 56.65 concentrate c 15.20 9.10 26.44 83.09 mountains 63.19 1.40 16.91 100.00 task 10.00 5.23 100.00 Example 2 Concentrate a 12.93 22.95 58.14 57.14 Concentrate b 7.26 13.55 18.94 76.08 Concentrate c 8.64 4.90 8.15 84.23 Mountains 71.17 1.15 15.77 100.00 Task 100.00 5.19 100.00 Example 3 Concentrate a 6.08 28.70 34.18 34.18 Concentrate b 3.87 24.90 18.90 53.08 concentrate c 6.11 14.50 17.33 70.41 mountains 83.94 1.80 29.59 100.00 task 100.00 5.10 100.00 Example 4 Concentrate a 9.30 11.25 19.69 19.69 Concentrate b 13.75 13.50 34.96 54.65 concentrate c 13.42 10.60 26.79 81.44 mountains 63.53 1.55 18.56 100.00 Task 100.00 5.30 100.00 Product% by weight Cu content Cu output Example 5 Concentrate a 7.32 8.70 12.30 12.30 Concentrate b 7.83 12.75 19.28 31.58 Concentrate c 11.36 13.70 30.09 31.67 Mountains 73.49 2.70 38.33 100.00 Task 100.00 5.17 100.00 The enrichment of oxidic copper ore in the examples 2 and 3 exceed the results obtained using waterglass alone according to Example 1. As can be seen from the table, according to Example 1, 36.81% the material used (conc. 1 to 3) swam away; this contained 83.09 % of the total existing copper, or 11.8% copper, based on that which was floated out Concentrate. The proportion of ore used (conc. 1 to 3), on the other hand, was lower at 28.83%, but it achieved 84.23% of the total existing copper a better yield. This yard corresponds to a copper content of 15.17%, based on the RonK concentrate that has swum out. This was an increase of the copper content by 3.37 units, corresponding to 28%. With increased addition Methylhydroxyäthylcellulose (Example 3) even became a copper concentrate of 22.38 percent by weight copper is achieved. This value almost doubles the copper content compared to that obtained in Example 1 (11.8%).

A consideration of each of the 1 concentrates (a) of the standard experiment and the concentrates obtained in Examples 2 and 3 make this particularly selective acting resp. oppressive effect of methyl hydroxyethyl cellulose on talc, clay and sludge-forming minerals in the flotation of oxidic copper ores clearly, namely 11.4% against 22.95 and 28.70% copper.

For comparison, in Example 4 and Example 5, in addition to sodium silicate Carboxymethyl cellulose added as a pusher reagent. The average substitute The degree of ion of this cellulose ether was 0.65 to 0.75. The viscosity, measured according to Höppler at 200 ° C. was for the carboxymethyl cellulose used in Example 4 6 to 9 cP (in 2% solution) and for the 1000 to 2PPP used in Example 5 cP (in 5% solution). The carboxymethyl cellulose used in Example 5 was uncleaned; it contained those used in its manufacture from alkalized cellulose and salts produced by sodium monochloroacetate (total salt content 35%).

The copper content of the concentrates and the copper output in Be game 4 and Example 5 was significantly less than when using Methylhydroxyäthylce-llulose in example and example 3 and also less than when sodium silicate is used alone according to example 1.

Claims (4)

Claims 1. Process for the flotation of copper ores with predominantly oxidic ones Proportions using common collector, foamer and activation reagents, characterized in that as a pusher for talc, clay and other sludge-forming Mineral alkyl or alkyl hydroxyalkyl cellulose can be used. 2. A method for the flotation of copper ores according to claim 1, characterized characterized in that cellulose ethers are used as pusher, in which per glucose unit on average about 1 to 2, preferably 1.4 to 1.6 of the total of 6 hydroxyl groups by alkyl groups with 1 or 2 carbon atoms and / or by hydroxyalkyl groups are etherified with 2 or 3 carbon atoms. 3. Procedure. for the flotation of copper ores according to claims 1 or 2, characterized in that methylhydroxyethylcelluloses are used as the trigger in which the proportion of hydroxyalkyl ether groups is about 10 to 30% of the number of the alkyl ether groups. 4. A method for the flotation of copper ores according to claims 1 to 3, characterized in that the cellulose ethers together with alkali silicates as a push button be used.