Progress in separation of copper and arsenic flotation
MULTIPURPOSE UTILIZATION MULTIPURPOSE UTILIZATION
(Chengdu Institute of Mineral Resources, Chinese Academy of Geological Sciences, Chengdu 610041, China )
Abstract discusses the status and progress of domestic and international copper flotation separation of arsenic in recent years, introduced the arsenic sulfide mineral floatability characteristics and main methods of the current copper flotation separation of arsenic, focuses on the new agents arsenic copper flotation separation Research and application.
Keywords arsenic copper separation flotation of collector inhibitor
The world's copper resources are abundant and widely distributed. There are copper resources in more than 150 countries on five continents, and the reserves are relatively concentrated. China's copper mines are not only widely distributed, but also have a complete industrial type. The most important ones are porphyry, skarn, layered, volcanic and copper- nickel sulfides. The copper reserves of these five types of deposits account for China. More than 90% of total copper reserves. China's copper mines are mainly sulfide ore. Among the proven reserves, sulfide ore accounts for 87%, oxidized ore accounts for 10%, and mixed ore accounts for 3%. Copper sulfide minerals mainly include chalcopyrite, chalcopyrite, porphyrite, beryllium copper and copper blue. It was often coexist with dense copper pyrite, arsenopyrite and the like. Among the 15% of the world's copper resources, the ratio of As/Cu is 1:5. The main arsenic-containing minerals are toxic sand (FeAsS) and orthorhombic arsenic iron (FeAs 2 ), which contain 46% and 73% arsenic, respectively. They are similar to the conditions for the formation of copper sulfide minerals, and some have similar physical and chemical properties. Therefore, when flocculating copper sulfide minerals with sulfhydryl collectors, arsenic minerals such as toxic sand are often mixed into concentrates, causing arsenic in copper concentrates to exceed the standard, seriously affecting the quality of copper smelting products, and some arsenic will be converted into Arsine, arsenite and organic arsenic compounds corrode equipment, pollute the atmosphere, and poison the environment. Therefore, studying the separation of copper and arsenic is of great significance.
1. The suspensibility of arsenic
Drastic et al. used electron diffraction to study the phase composition of the oxidation products on the surface of arsenopyrite under various pH conditions. Studies have shown that in a strongly acidic medium (pH<3), the surface of the arsenopyrite is oxidized to form Fe 2+ , Fe 3+ , Fe(OH) + , Fe(OH) + 2 and elemental S, which can strengthen the yellow drug collector. The adsorption capacity, so the arsenopyrite floats well in acidic media. In the neutral and strong alkaline medium, a hydrophilic Fe(AsO 4 )·2H 2 O film is formed on the surface of the arsenopyrite. The presence of the oxidant will strongly promote the formation of this arsenate and make the arsate floatable. reduce. In alkaline media, the oxidation of the surface of the arsenopyrite is:
FeAsS + 11H 2 Oâ†â†’Fe(OH) 3 + HAsO 2- 4 + SO 2- 4 + 18H + - 14e
(E o =0.569V)
Iron hydroxide is deposited on the surface of the arsenopyrite, sulfur is oxidized to SO 4 2- , S 2 O 2 - 3 and so on into the solution, and arsenic acid ions such as HAsO 2 - 4 and H 2 AsO 4 are further reacted to form FeAsO 4 . X-ray photoelectron spectroscopy confirmed that these FeAsO 4 precipitates were densely coexisted with Fe(OH) 3 on the surface of the arsenopyrite, and the formed hydrophilic membrane could prevent the adsorption of the collector and make the poisonous sand hydrophilic and inhibited. Therefore, the floatability of the arsenopyrite decreases linearly between pH 6 and 11. It is basically non-floating at pH 9.5, and is completely inhibited at pH >11. When an oxidizing agent such as hydrogen peroxide or sodium hypochlorite is added at a pH of >7, the inhibitory effect of arsenopyrite will be enhanced.
2 , the main method of copper arsenic flotation separation
According to the buoyancy characteristics of arsenic, the researchers at home and abroad have carried out a more in-depth study on the separation of copper and arsenic flotation, and summarized the following methods for flotation separation of copper and arsenic:
1) Use highly selective collectors. Use selective collectors to expand the floatability difference between the two minerals to sort copper and arsenic, such as some new high-efficiency collectors and some combination agents.
2) A combination of lime-based inhibitors is used. Asbestos, like sulfide minerals, has different critical pH values. Many studies have shown that the use of lime and alkaline adjusting agent may be a metal sulfide minerals arsenopyrite separated to a certain extent.
3) Oxidation method. The arsenopyrite is more easily oxidized. The aerobic oxidation (pH 5.7~6.5), long-time stirring or adding various oxidants can strongly inhibit the floatability of the arsenopyrite. Commonly used bleach oxidant, potassium permanganate, potassium weight chromium and manganese dioxide. The order of strength of these oxidants is: bleaching powder > potassium permanganate > potassium dichromate > manganese dioxide.
Increasing the temperature of the slurry accelerates the oxidation process. A large number of experimental work shows that in the case of increasing the temperature of the slurry, the order of oxidation of some sulfide minerals is: arsenopyrite > pyrrhotite > pyrite > chalcopyrite. The control temperature is 40~50 °C, which can strengthen the inhibition of poisonous sand.
4) Inorganic inhibitors such as thioacids are used. The arsenopyrite was inhibited with thioacid or thiosulfate. The test results showed that the order of inhibition of the arsenopyrite was: Knox's agent> thiosulfate> sodium sulfite.
5) Use organic inhibitors. Including dextrin, tannin, lignosulfonate, polyacrylamide and the like. It has also been found that the combination of an organic inhibitor and an inorganic inhibitor is more effective.
6) Use arsenic re-grinding, increase the number of selections, etc. to remove arsenic.
3. Research and application of new agents for copper-arsenic flotation separation
Although there are many ways to separate copper and arsenic flotation, the high index of copper arsenic flotation separation depends to a large extent on the flotation agent, namely the effective inhibitor of arsenic minerals and the special collector of copper minerals. In this regard, the majority of scientific research workers at home and abroad have invested a lot of effort, conducted in-depth research, developed a number of effective inhibitors of arsenic minerals and special collectors of copper minerals.
3.1 Research and application of arsenopyricide inhibitor
Xiong Daoling and Luo Xuyan investigated the flotation behavior of chalcopyrite and arsenopyrite and the effect of DL inhibitors on their floatability. The results showed that under the action of butyl xanthate collector, chalcopyrite had better floatability without DL inhibitor, and the floatability of arsenopyrite decreased significantly with the increase of pH value of solution. DL inhibitors can well inhibit the flotation of arsenopyrite without affecting the flotation of chalcopyrite, expanding their floatability gap and showing good selectivity. When the pH of the slurry is >4, the DL inhibitor When the dosage is more than 10 mg/L, the poisonous sand is almost completely inhibited.
Yang Meijin et al. used a different inhibitor such as lime, potassium hypochlorite, potassium permanganate, citric acid and DAS for a high arsenic copper mine to carry out arsenic reduction test. The results show that the new arsenic removal agent DAS has the best effect on separating copper and arsenic, and can effectively inhibit the arsenopyrite without affecting the recovery rate of chalcopyrite. The results of flotation test of high arsenic copper ore with 6.22% arsenic indicate that the arsenic content of copper concentrate can be reduced to 0.43% and the copper recovery rate is 94.46%. [next]
Ji Jun studied the properties of arsenopyrite and its flotation and inhibition under various medium conditions. It was found that the flotation separation of arsenopyrite with copper, lead , zinc and other sulfide minerals not only relies on high pH, ​​but also with pulp. Ion composition and changes in the surface properties of minerals are closely related. The experiment used DLG to suppress the arsenopyrite. By adjusting the ion composition in the slurry, the surface properties of the arsenopyrite were changed to inhibit it. The arsenic removal rate was over 99%, and a good sorting effect was obtained.
The high-molecular organic inhibitor YFA has a strong inhibitory effect on arsenopyrite, especially in alkaline media, which can successfully inhibit arsenopyrite and achieve copper-arsenic separation. Zeng Meiyun used a modern testing technology (wetability, adsorption capacity, AES) to systematically study the high molecular organic inhibitor YFA. It is believed that YFA selectively chemisorbs on the surface of the arsenopyrite to form a hydrophilic film. Preventing and masking the adsorption of the collector is the root cause of the inhibition of the arsenopyrite.
Li Yufen et al used the CCF combination inhibitor for the flotation separation test of a high-arsenic copper ore in Guangxi. Under the appropriate process and pharmaceutical system conditions, copper content was 28.97%~29.65%, arsenic 1.06%~0.91%, copper recovery. The copper concentrate with a yield of 89.12%~92.82% has a good effect. The CCF combination agent inhibits the arsenopyrite by preventing the activation of copper ions and forming a hydrophilic colloid film on the surface thereof, and has obvious deactivation effect on the copper ion-activated arsenopyrite without affecting the chalcopyrite floatation. .
Tang Xiaolian used the Harrison flotation tube test to study the effects of various inorganic and organic modifiers on the separation of copper and arsenic. The experimental results show that the use of a single inorganic modifier such as lime, sodium sulfide or potassium permanganate to separate copper and arsenic has no obvious effect, and can effectively separate copper and arsenic, while alkaline earth metal salts and heavy metal ions and sodium humate mixture Can effectively achieve copper and arsenic separation.
Taohong Chun introduced the practice of copper minerals arsenopyrite and tetrahedrite tin ore to separate copper-based Yaogangxian tungsten ore, discussed off the drug, grading influence the particle size of the flotation reagent system and other indicators. The test results show that the combination of lime and sodium sulfite has the best inhibitory effect on arsenic, and the float copper is best mixed with ethyl sulphide and ethyl sulphate. When the ore contains 2.1% copper and 30.2% arsenic, the industrial test process and the pharmaceutical system are used. The copper grade in the copper concentrate can reach 18.1% and the arsenic content is 2.8%.
Ji Jun, He Zheng, etc., through the study of the flotation separation factors of arsenopyrite and polymetallic sulfide ore, it is proposed to use CaCl 2 as an inhibitor of arsenopyrite, so that the arsenic content of each flotation concentrate product is reduced to below 0.5%. , effectively achieve flotation and reduce arsenic. The process has been successfully used in industrial production and has achieved good economic benefits.
Chen Hong, Dai Shujuan and others for the high arsenic refractory copper ore with high arsenic content, high oxidation rate and complex embedding state. Based on a large number of experimental studies, it is determined to use stage grinding and coarse concentrate regrind. Fine-tailed and re-grinding process. Sodium sulfide was used as precipitant and vulcanizing agent. Sodium thiosulfate and ammonium chloride group cooperated with arsenic inhibitors to successfully separate copper and arsenic. Good selection index was obtained.
Jin Huaai, Peng Zhihong and Zeng Meiyun selected high molecular organic lignin sulfonate, polyacrylamide and fulvic acid as inhibitors to investigate their inhibitory properties on chalcopyrite and arsenopyrite, and studied the activation of these organic compounds with Cu 2+ . The role of the post-mineral. The results showed that the three organic substances studied had obvious inhibitory effects on arsenopyrite, but had no effect on the planktonic activity of chalcopyrite, and the separation of chalcopyrite and arsenopyrite could be realized. Furthermore, the verification test of artificial mixed ore and natural ore was carried out, and the artificial mixed ore and natural copper-arsenic mixed concentrate after being treated by Cu 2+ were successfully separated.
Tang Xiaolian and Qian Xin used the Harrison flotation tube test to study the role of sodium humate in copper and arsenic sorting. It was found that sodium humate had a significant deactivation effect on the arsenopyrite activated by copper ions. The use of sodium humate enables copper and arsenic sorting in the pH range of 9-11. The deactivation of sodium humate on arsenopyrite is due to the fact that sodium humate can not only complex the copper ions on the surface of the arsenopyrite, but also adsorb a large amount of hydrophilic colloidal film to form a hydrophilic colloid film, thereby inhibiting the arsenopyrite.
He Xiaochuan et al. found that the factors affecting the floatability of arsenopyrite in the separation of lead arsenic, copper and arsenic and how to avoid the activation of arsenopyrite, found that adding sodium sulfide and lime mixed agent to the ball mill can not only eliminate the copper ion pair well. The activation of arsenopyrite, but also can make the leaching of galena and chalcopyrite remain basically unchanged, thus effectively achieving the separation of lead arsenic, copper and arsenic.
The Japanese patent reported that soda or lime and cyanide were added to the mixed concentrate, and the mixture was stirred at a pH of 10.5 to 11.5, and the pH was adjusted to a weak acidity (pH 5 to 7) with sulfuric acid or sulfurous acid without a collector. The copper arsenic mineral can be separated by using only the foaming agent to float the chalcopyrite. The flotation of the actual production scale is carried out with the mixed concentrate of a mine as the raw material. When the copper-arsenic mixed concentrate contains 3.81% copper and 15.28% arsenic, the copper concentrate grade is 19.4%, the arsenic content is 0.24%, and the copper operation A good indicator of a recovery rate of 92.4%.
Since conventional inhibitors such as lime, cyanide, sulfide and permanganate are not effective in separating sulfur-arsenic copper from chalcopyrite, Yen WT et al. have found two preferential flotation methods through research. The separation of sulfur-arsenic copper ore and chalcopyrite is effectively realized. The first one is when the yellow medicinal amount is 20mg/L, the inhibition of chalcopyrite and the flotation of arsenic sulphide ore at a potential of -250mV and pH 9.0; the second is at the same pH and xanthate concentration. The 250 mg/L magnesium ammonium mixture inhibits the sulfur-arsenic copper ore and floats the chalcopyrite to achieve flotation separation of the sulfur-arsenic copper ore and chalcopyrite. Infrared spectroscopy of the mineral surface showed that a hydrophilic complex anion was found on the surface of the sulphide arsenic, while the chalcopyrite surface did not adsorb the complex. The copper concentrate obtained by artificial mixed flotation with arsenic containing 1.73% contains only 0.14% arsenic and the arsenic removal rate is as high as 92%.
3.2 Research and application of copper mineral special effect collector
The former Soviet Central Geological Exploration Institute used isonicotinate to treat complex gold, copper, arsenopyrite ore. Isonicotinic acid esters can float gold, cuprous gold, natural copper and chalcopyrite well, but not pyrite and arsenopyrite. The flotation is carried out in two stages: the first stage uses isonicotinate to obtain a gold-copper concentrate containing arsenic in accordance with the standard; the second stage uses a xanthate to obtain a product containing gold-arsenic pyrite. This agent guarantees the preferential flotation of natural gold and chalcopyrite without the use of inhibitors. The effect of combined flotation was confirmed under industrial conditions.
Yu Xue, Huang Xinting and others conducted a crude remineral regrind process test based on the particle size composition characteristics and mutual intercalation relationship of an arsenic-containing copper mineral. The sth inhibitor was used to inhibit the arsenopyrite, and the copper mineral was floated by the selective Sk-1 flotation agent to achieve the purpose of reducing arsenic and improving the copper recovery rate of the copper concentrate.
Gao Qipeng used ethyl thiourethane as a gold-copper mineral collector and sodium sulfite as an inhibitor of arsenic minerals in the study of arsenic reduction in the gold-copper concentrate of Hunchun Gold and Copper Mine. The 0.74% fell below 0.4%, the copper grade increased from 10% to over 15%, the gold recovery rate also increased slightly, and the copper recovery rate increased by 3.0~5.0%.
Meng Shuqing and others studied the high-arsenic polymetallic sulfide ore flotation and arsenic reduction. It was found that ethyl sulphide and amine sulphate have the same effect, which can make the arsenic containing more than 3% of arsenic produced in Hunan Yaogangxian tungsten mine over the years. Concentrate arsenic is reduced to about 0.5%, and it is considered that the combination of these two agents and xanthate is better than 3:5, respectively.
The metal minerals in the ore of the Lianhuashan copper mine in Inner Mongolia are mainly chalcopyrite, pyrite and arsenopyrite. Tang Baolin et al. conducted a small-scale test and industrial test on the arsenic reduction of copper concentrate in the ore properties. The test used lime and sodium thiosulfate as the toxic sand inhibitor, and methyl thiourethane and aniline black drug as the copper mineral collector. And the use of coarse concentrate re-grinding, increasing the number of selections and other measures to solve the problem of high arsenic in the copper concentrate of the mine, copper concentrate containing arsenic fell below 0.5%, reaching the national standard copper concentrate containing arsenic standard.
When He Xiaochuan and other high-arsenic polymetallic sulphide ore were treated, a large number of process exploration experiments and various conditions were studied. Finally, copper-lead preferential step-by-step mixing and coarse selection, mixing of coarse concentrate regrind process, and sodium carbonate were used. Copper and lead mixed coarse selection of pH adjuster, ethyl xanthate + Z-200 as a collector, obtained a very good index. The arsenic content of copper-lead mixed concentrate and zinc concentrate decreased to about 0.5%, and the recovery rate of each useful metal in the concentrate reached more than 90%.
4. Conclusion
In summary, the flotation separation of copper and arsenic has always been a major problem in the field of mineral processing . In response to this problem, domestic and foreign mineral processing workers have made great progress in the separation of new agents and processes for copper and arsenic flotation after many years of research, and summarized several effective ways to separate copper and arsenic flotation. The research and application of high-efficiency inhibitors of arsenic minerals have solved the problem of arsenic reduction in copper concentrates of some selected factories to some extent, and created great economic benefits for enterprises. With the continuous exploitation and utilization of copper resources, the easy-to-select copper resources with simple ore content and less impurity content are less and less. Therefore, further exploration and research on the flotation separation of difficult-to-select high-arsenic copper ore is particularly important. At present, in order to more effectively recycle copper resources, reduce the arsenic content of copper concentrates, and achieve the flotation separation of copper and arsenic, we should strengthen the research and development of new chemicals, especially the relatively slow progress of copper and arsenic separation. In addition to the development and development of highly efficient selective collectors, it is necessary to strengthen the research and exploration of new processes and methods for copper-arsenic flotation separation.
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