Research and Application of Copper Oxide Flotation Activator

For the flotation of copper oxide, in addition to collector plays a vital role outside, an activator is also very important. Especially for refractory copper oxide ore, it is difficult to use conventional vulcanization flotation, and the addition of a new activator can completely change the entire flotation process.

Activators can be divided into two broad categories: inorganic activators and organic activators. There is no need for an activator such as the commonly used vulcanizing agent sodium sulfide, and sodium hydrogen hydride is also used abroad, but it is not common. The use of calcium sulfide as an activator from the 1970s, in the application of the Dongchuan Mining Bureau, has played a role in reducing costs and improving flotation indicators. In addition, ammonium sulfate and other inorganic salts are also used.

Organic activator ethylene diamine with phosphorous acid, benzotriazole (BTA) and dithiol oxadiazol-dithiobis (D ₂₎ and the like.

I. Ammonium sulfate

Ammonium sulfate (NH ₄ ) ₂ SO _{4 has been} used as an activator for copper oxide ore flotation. It has been widely used in the country since the 1960s and 1980s, and has achieved remarkable results.

Such as ammonium sulphate in several industrial test results of the copper oxide DONGCHUAN PBM beneficiation plant shown in Table 1. It can be seen from Table 1 that after the ammonium sulfate is used in the high oxidation rate copper ore of the Shutianba plant, the copper recovery rate is increased by about 5%, and the concentrate grade is increased by about 4%. After the use of ammonium sulfate in the polling plant, the recovery rate increased by about 3% under the conditions of similar concentrate grades.

Table 1 Industrial test results using sodium sulfate

In the flotation process of copper oxide ore, the role of ammonium sulfate is mainly to not only activate the flotation of copper oxide minerals, but also improve the selectivity of the flotation process. At the same time, ammonium sulphate significantly speeds up the flotation.

Some scholars have studied the mechanism of ammonium sulfate as a flotation activation mechanism of copper oxide ore. It is considered that ammonium sulfate should be a "vulcanization accelerator". Because ammonium sulfate itself does not activate the copper oxide ore flotation in the absence of sodium sulfide. A large number of experiments have also proved that the optimum amount of ammonium sulfate is closely related to the amount of sodium sulfide. When the amount of sodium sulfide is high, the amount of ammonium sulfate should also be high, and the optimum ratio of the two is 1:1.

The true effect of ammonium sulfate is as follows: (1) Catalytic effect, accelerate the vulcanization rate of malachite, promote the thoroughness of the reaction, and thus avoid the inhibition of residual sulfide ions on the vulcanized malachite. (2) Stabilizing effect, increasing the density of the vulcanized film formed on the surface of the malachite, and enhancing the stability of the vulcanized film. (3) Hydrophobic effect, which improves the adsorption rate, adsorption capacity and adsorption stability of xanthate on the surface of malachite, thereby imparting stronger hydrophobicity to malachite.

Second, ethylene diamine phosphate

Ethylenediamine phosphate (also known as ethylenediamine phosphate) is a new type of copper oxide ore flotation activator developed by the Dongchuan Mining Bureau Central Laboratory in 1964. It is a product formed by the direct reaction of ethylenediamine with phosphoric acid.

Its structural formula is:

Ethylenediamine phosphate is a white, odorless, finely crystalline solid that is soluble in water and is very stable. Its aqueous solution has a strong ability to dissolve natural copper oxide minerals while producing a purple copper ammonium complex. The purple copper-ammonium complex can be directly collected by butyl xanthate or by the action of sodium sulfide to form copper sulfide, followed by flotation with butyl xanthate.

The addition of ethylenediamine phosphate is generally carried out in an aqueous solution and is added separately to the one-stage and two-stage ball milling.

Through the small and industrial tests of several copper oxide ore dressing plants in the Dongchuan Mining Bureau, after gaining experience, they were gradually applied in production from 1980 to 1985, and achieved remarkable results. The production results of the use of ethylenediamine phosphate in several plants of Dongchuan Mining Bureau are shown in Table 2.

Table 2 Industrial application results of ethylenediamine phosphate

Note: Ethylenediamine in the table refers to ethylenediamine phosphate.

It can be seen from Table 2 that the addition of ethylenediamine phosphate has a different degree of copper recovery in each selected plant. For the Shutianba plant, the ore oxidation rate is 77.7%~80.46%, and the copper recovery rate is 9.24%. The copper oxide recovery rate is increased by 11.24%, the sodium sulfide dosage is reduced by 34%, and the Dinghuang dosage is reduced by 8%. The oxidation rate of the ore is 32.4%. After the addition of ethylenediamine phosphate, the copper recovery rate is increased by 2.23%, wherein the copper oxide recovery rate is increased by 5.59%, the copper sulfide recovery rate is increased by 0.64%, and the sodium sulfide dosage is decreased by 22%. The amount of the drug was reduced by 43%. The oxidation rate of falling snow ore is 32%. With ethylenediamine phosphate, the recovery rate of copper is increased by 3.24%, among which the recovery rate of copper oxide is increased by 6.08%, the recovery rate of copper sulfide is increased by 1.75%, the dosage of sodium sulfide is decreased by 34.02%, and the dosage of Dinghuang is reduced. Reduced by 8.54%.

The results also show that the addition of ethylenediamine phosphate, ore with high oxidation rate, has a large increase in copper recovery. The volcanic rate of the Shutianba ore is the highest (77%~80%), and the copper recovery rate is increased by 9.24%. When the oxidation rate of the ore is 32%, the recovery rate is increased by 5.37%; when the oxidation rate is 32%, the increase is 3.24%. From the analysis of the situation, the addition of ethylenediamine phosphate is mainly to improve the recovery of combined copper oxide.

Due to the large amount of primary and secondary slime in the copper oxide ore of Dongchuan, the selectivity of the flotation process is destroyed, a large amount of chemicals are consumed, and the operation is also very difficult. After the use of ethylenediamine phosphate, the sludge hazard is basically eliminated, so the amount of flotation agent is also significantly reduced. This can also be verified from the application results of the above copper oxide ore dressing plant.

In order to further improve the recovery rate of Dongchuan copper oxide ore, “secondary activation” flotation method is adopted, that is, before adding Na ₂ S, ethylene diamine phosphate is used as an activator of copper oxide mineral, and Na ₂ S is added. After the surface of the copper oxide mineral forms a stable vulcanization film similar to copper sulfide mineral, the inorganic phosphate is used as an activator of the copper sulfide mineral (including the sulfided copper oxide mineral) to make the copper sulfide mineral hydrophobic. Increased sexuality, accelerated flotation speed, and increased recovery rate. According to the actual situation, it is determined that ammonium phosphate is a secondary activator. In addition, it has also been found that ethylenediamine phosphate also has a significant effect on increasing the recovery rate of copper oxide associated silver .

In addition to ethylenediamine phosphate, the industrial test results of its homologue propylenediamine phosphate showed that it also had substantially the same effect as ethylenediamine phosphate.

The activation mechanism of ethylenediamine phosphate on copper oxide minerals is mainly because it can significantly increase the adsorption rate and adsorption amount of minerals on sodium sulfide and xanthate, thereby improving the flotation of copper minerals.

Some people have studied the pure minerals of the malachite of Dongchuan and the malachite of Guangdong Dendrobium. The activation of copper minerals by ethylenediamine is controlled by the micro-dissolution. Chrysocolla uses ethylenediamine phosphate as an activator, which can be better captured by the smectin if it needs to be vulcanized. The presence of sodium sulfide has little effect on the further improvement of the recovery rate of chrysocolla flotation. After malachite is treated with ethylenediamine phosphate, it is difficult to float with xanthate or vulcanization-xanthate due to excessive dissolution of copper ions, but the flotation of malachite becomes better after washing. Therefore, the addition of a small amount of ethylenediamine phosphate to the copper oxide ore containing chrysophane can increase the recovery rate and reduce the amount of sodium sulfide and yellow drug.

Third, benzotriazole and dithiol thiodiazole

Dithiol benzotriazole and thiadiazole is from Kunming Institute of Metallurgy reference to a new class of organic activator is an overseas information independently developed.

(1) The nature of the medicament. Benzotriazole is abbreviated as BTA, and its structural formula is:

It is a highly effective corrosive agent for copper and its alloys and produces a highly insoluble protective layer on the surface of copper or copper oxide. Copper and BTA are alternately combined to form a linear structure similar to a polymer. On the surface of the chrysocolla, a similar polymer may also be produced to stabilize the surface, resulting in an improvement in floatability. It must be dissolved in an organic solvent (alcohol) before use.

Dithiophenol thiodiazoles are 2,5-thiophenol-1,3,4-thiodiazole (abbreviated as DMTDA) with various isomers. DMTDA decomposes at 168 ° C, is insoluble in chloroform, benzene and water, only slightly soluble in hot alcohol, but very soluble in lye, can form a chelate with a variety of metal ions. The Kunming Institute of Metallurgy has mass-produced the mineral dithiophenol thiodiazole-D ₂ , which is a yellow to purple red liquid with a density of 1.4g/cm ³ and PH13. Do not need to be diluted when used, can be added directly.

(b) Experimental studies of BAT and DMTDA (D ₂ ). The activation flotation results of the Tonglushan copper oxide ore by BAT and DMTDA (D ₂ ) of Kunming Institute of Metallurgy are shown in Table 3. It can be seen from the table that DMTDA or industrial products D ₂ and BTA are effective activators of the copper oxide ore. Among them, the D ₂ agent has the best sorting effect, and the concentrate grade is compared with the conventional vulcanized-xanthate flotation. And the recovery rate increased by 1.72% and 5.62%, respectively.

Table 3 Test results of BTA/DMTDA(D ₂ )-diesel flotation copper record mountain ore

The industrial test results of Xiaojie Copper Oxide Mine showed that D ₂ (950g/t) diesel (230g/t) was added during the flotation of xanthate-xanthate, and the recovery rate of the plant was increased from 40% to 50%. This sorting effect is almost the same as that of BTA-neutral oil flotation. However, when BTA-diesel flotation, there is no need to add a class of collectors such as xanthate. In the case of DMTDA (D ₂ )-diesel flotation, only the right amount is added at the same time. Yellow medicine can get good sorting indicators.

Through these studies, it can be seen that when BTA or DMTDA (D ₂ ) is mixed with Dinghuang medicine for flotation of certain copper oxide ore, the selectivity of the process is still high while the flotation recovery rate is significantly improved.

DMTDA flotation copper oxide ore is a new process independently developed by Kunming Metallurgical Research Institute. The institute can provide DMTDA (flotation agent D ₂ ) for mining at a price less than 1/10 of that of BTA.

The use of D ₂ activator not only improves recovery and concentrate grade, increases flotation rate, reduces other drug consumption (with or without addition of sodium sulfide), but also floats copper sulfide and copper oxide at the same time (reduced flotation service) operation).

The successful test of flotation agent D ₂ basically solved the problems existing in the application of BTA. Because the flotation agent D ₂ flotation performance is similar to BTA, and the flotation agent D ₂ is much lower than BTA, it can be directly added without dilution, and no organic solvent is needed.