This paper introduces the characteristics of arsenic resources in China, the necessity of arsenic removal and the reasons for the difficulty in selecting arsenic-containing ores. The research progress of arsenic removal in arsenic-containing ores at home and abroad in recent years is reviewed, and various arsenic removal agents and processes are reviewed. After analyzing and discussing, the development direction and trend are proposed. Arsenic is widely present in the world. The abundance of arsenic in the earth's crust is about 2 g/t. Since arsenic is a sulphur-rich element, many sulphide ores are associated with arsenic. About 150 kinds of natural mineral arsenic, arsenic mainly pyrite and arsenopyrite, mostly found in high temperature and warmed fluid deposit, and often with brass pyrite, pyrrhotite, stibnite, square lead ore, sphalerite, cassiterite and other minerals and precious metal sulfide gold silver intimately associated. In addition, sulfur arsenic copper ore and orthorhombic arsenic are also common. According to statistics, 15% of the world's copper resources have a ratio of arsenic to copper of 1:5, and 5% of gold resources have an arsenic ratio of 2000:1. In almost all cases, arsenic is an undesirable impurity. The presence of arsenic in mineral processing not only affects the quality of concentrate products. Unfavorable sales and sales, but also affected the subsequent metallurgical treatment process, and brought serious environmental problems. With the improvement and strictness of environmental legislation, the arsenic content allowed in smelting concentrate products is also decreasing. Research progress on arsenic removal by As l arsenic sulfide ore in smelting concentrates
1.1 Separation of arsenic-bearing copper ore and copper sulfide ore Copper-arsenic separation is a major problem in the field of mineral processing. Many studies on copper-arsenic separation have been conducted at home and abroad. There are three main sources of arsenic in copper concentrate: 1 arsenic exists in copper minerals in the form of isomorphism, which cannot be separated by flotation, but usually has little effect on arsenic in copper concentrate; 7 arsenic-containing copper Minerals such as sulphur arsenic copper ore, arsenic bismuth copper ore are enriched in copper concentrates; 3 arsenic-containing minerals (mainly toxic sand) are mixed. Sulfur arsenic copper ore (Cu3AsS4) is the most common arsenic-bearing copper ore. Because the sulphide arsenic ore and its associated copper sulphide ore (copper blue Cu2S, chalcopyrite cuzs, chalcopyrite CuFeS2, etc.) have similar surface properties, the selectivity is also very close, so in the conventional flotation process, arsenic Copper mines will inevitably enter other concentrates with other copper minerals. Solving the problem of arsenic-bearing copper ore can be started in two ways: by suppressing the sulphur-arsenic copper ore in the flotation of copper minerals, or by selectively removing the sulphur-arsenic-copper ore in the final copper concentrate. Many scholars have studied the electrochemical properties and flotation characteristics of sulfur-arsenic copper ore. Several scholars have proposed the results of the reaction of sulphur arsenic copper ore with xanthate. In order to find out the optimal flotation potential of sulphur-arsenic copper ore, H. Gong studied the potential and wettability of sulphur-arsenic copper ore in pentyl potassium xanthate (PAX). Tajadod and Yen have reported that under the usual mixed flotation conditions, xanthate is used as a collector . The surface characteristics and flotation properties of sulphide arsenic and chalcopyrite are almost the same. Conventional inhibitors such as lime and cyanide , sulfides, and potassium permanganate can not effectively achieve the separation enargite and copper sulfide. They briefly mentioned the reduction of arsenic in copper concentrates by MAA ( magnesium ammonium phthalate: 0.5M hexahydrate magnesium chloride, 2.0 M ammonium chloride, 1.5 M ammonium hydroxide). s H Castro and S Honores studied the surface properties and floatability of sulphur arsenic copper ore by measuring the zeta potential of sulphur-arsenic copper ore, the electrostatic potential of bismuth arsenic copper ore and the Hamiltonian tube test. A sulfonate mineral that is easily floated by xanthate, the presence of a thioarsenate group on its surface makes it more resistant to oxidant inhibition than any other copper sulfide in an alkaline medium. The results of research on controlling the slurry potential and flotation of sulfur-arsenic copper ore have been published. These results indicate that the adjustment of the slurry potential can separate the sulfur-arsenic copper ore from the copper sulfide ore flotation. WT Yen and J Tajadod studied two preferential flotation methods for sulphide arsenic and chalcopyrite, and effectively achieved arsenic removal from chalcopyrite. One is that the yellow medicinal amount is 20 mg/L, and the potential is One 250 mV, pH=9.0, inhibiting chalcopyrite and reverse flotation of sulphur arsenic copper ore; the other is to suppress sulphur arsenic copper ore flotation with 250 mg/L MAA at the same pH and xanthate concentration mine. Jaime and Cifuentes also attempted to reduce the arsenic content in copper concentrates by changing the potential of the gap. With this method, the grade of arsenic decreased from 0.72% to 0.32%. However, the selectivity of controlling the slurry potential flotation method in industrial applications is not high. Another significant property of sulphur arsenic copper ore is its resistance to the inhibition of strong oxidants. Accordingly, Hunch (1993) applied for a patent for selective oxidation of chalcopyrite with H202 and other oxidants, and selective flotation of sulphur-arsenic copper from chalcopyrite copper concentrate. D.Fomasiero et al. proposed a selective oxidation-dissolution separation method based on the selective oxidation sites of minerals: selective oxidation with H202 in a weakly acidic medium (pH=5.0), or in an alkaline medium (pH=11.0). The selective oxidation of surface oxides by oxidation of H202 followed by the addition of EDTA (strong complexing agent ethylenediamine tetraacetic acid) can well separate the arsenic-containing copper ore and copper sulfide ore. XPS analysis showed that the separation of these minerals with H2O2 is due to the fact that the arsenic-containing minerals are more oxidized than the arsenic-free minerals. In addition, it is worth mentioning that the application of bacterial leaching technology in the removal of arsenic. The principle of bacterial leaching of sulphur-arsenic copper ore in copper concentrate is: in the presence of H20 and 02, under the action of Thiobacillus ferrooxidans, Thiobacillus thiooxidans, Iron Ferrobacter and complex bacteria, sulfur-arsenic copper ore Direct leaching reaction occurred: Cu3AsS4+6H20+1302→4H3AsS04+4CuS04. Wen Jiankang of Beijing Research Institute of Nonferrous Metals, etc., through the bacterial leaching test on a flotation concentrate of arsenic low-grade copper sulfide ore in China, pointed out that through breeding Excellent leaching strains, which can effectively extract sulfur, arsenic and copper ore in copper concentrates. 1.2 Arsenic-containing minerals (toxic sand) and (gold-containing) sulfide ore are sorted with arsenic-containing arsenic-containing minerals and The separation of gold sulphide ore is a difficult task for minerals workers to study.
1.2.1 Research on the floatability of arsenopyrite shows that the arsenopyrite is easily oxidized in the water-gas medium of medium-strong alkali, and the surface forms a hydrophilic membrane similar to the structure of scorodite [Fe(AsO4)·2H20], especially in the oxidant. When present, this arsenate formation will be strongly promoted. The hydrophilic membrane can hinder the adsorption of the xanthate collector, thereby greatly reducing the floatability of the arsenopyrite, linearly falling between pH=6-11, and basically not floating when pH=9.5, when pH>11 Completely suppressed.
1.2.2 Research progress of flotation reagents for the separation of arsenopyrite and (gold-containing) sulfide ore. The new flotation reagents are mainly for the study of high-efficiency, low-cost, non-toxic or less toxic agents. (1) Highly selective collectors. The study of collectors for the separation of arsenopyrite and (gold-containing) sulfide ore is focused on the study of highly selective collectors. The collectors used are mainly sulfhydryl anionic, thioesters and amino acid collectors. It is well known that trithiocarbonate compounds formed during the preservation of xanthate reduce the ability of xanthate to form metal xanthate on the surface of sulfide minerals. The alkyl trithiocarbonate (R-s-CS-SNa) can remove xanthate from the surface of the arsenopyrite mineral and reduce its hydrophobicity. Some scholars in the United States have applied for patents belonging to alkyl or aryl trithiocarbonate flotation reagents. BA Qianturia made a new IIPOKC agent based on butyl xanthate and excess chlorochlorohydrin, which consists of propylene trithiocarbonate (11TFK) and propoxylated sulfide ( OIIC) composition, the components of the IIPOKC agent are fixed on the surface of the arsenopyrite, which reduces the floatability of the arsenopyrite and prevents the adsorption of the xanthate on the surface of the arsenopyrite to make the surface hydrophilic. In the flotation of golden iron ore and arsenopyrite, the addition of IIPOKC before the xanthate can inhibit the arsenopyrite and improve the floatability of the pyrite. Meng Shuqing and others studied the high-arsenic polymetallic sulfide ore flotation and arsenic reduction, and found that ethyl sulphate fluoride and amine alcohol xanthate have the same effect, so that the arsenic-containing 3.00% copper concentrate produced over the years reduced arsenic to about 0.50%. It is considered that the combination of the two agents and the xanthate in a 3:5 ratio is better than the use alone. France uses potassium xanthate and mercaptobenzothiazole to float gold ore containing ore, and the grade of gold concentrate has been greatly improved. When Tang Xiaolian and others studied the separation of chalcopyrite and arsenopyrite, it was found that methyl thiourethane has significant selectivity and is an effective collector for copper and arsenic separation, while xanthate has almost no selectivity. The research on the application of amino acid collectors in arsenic removal of sulphide ore is more common in foreign countries. Former Soviet scholars used amino acid collectors to float non-ferrous metal sulfide ore from pyrite-arsenic ore. It was found that the combination of selective amino acid collectors and electrolytic solutions can improve the coloration of separated flotation concentrates. Metal recovery and the ability to sort small amounts of non-ferrous metals and precious metals from the main ore of pyrite and arsenopyrite. (2) Lime combined inhibitors. Aromatic sands have different critical pH values ​​than sulfide minerals. Lime is a commonly used alkaline pH adjuster that promotes the dissolution or oxidation of mineral surfaces. B. Bali and RSRichard believe that lime mainly inhibits sulfide ore by hindering the formation of double xanthate on the surface of sulfide minerals. However, the single lime method tends to be ineffective when the arsenopyrite or sulfide ore is activated or inhibited. Therefore, lime is often mixed with other agents to achieve better inhibition. Tong Xiong et al. added lime and ammonium salts (ammonium nitrate, ammonium chloride) into the slurry and found that the pyrite was not inhibited by the protection of the ammonium salt, while the arsenopyrite lost its floatability due to the inhibition of lime. The lime is mixed with sodium sulfite so that the arsenopyrite is inhibited by sodium sulfite in the slurry in which the lime is dissolved, and the sulfide ore remains in a floating state. For the combination of lime and copper sulfate, it is generally believed that the arsenopyrite activated by copper ions can maintain the planktonic capacity in the lime-adjusted slurry, and the pyrite is inhibited by the action of lime; or the sulfuric acid is added to the lime slurry. Copper can restore the suspended arsenopyrite to floatability, while pyrite is still in a state of inhibition. Studies have shown that when the ore contains a large amount of secondary copper minerals, lime can be used in combination with sodium sulfide. At this time, S- and Cu2+ form insoluble precipitates, thereby eliminating the activation of cu2+. He Zheng et al. believe that increasing the pH value of the slurry is beneficial to the separation of zinc and arsenic, because the optimum pH of the sphalerite flotation is 9-12, and at this pH, the surface of the arsenopyrite is easy to form FeAsO4 and Fe(OH)3. Therefore, the adsorption of Cu2+ on the surface is effectively prevented. The Beijing Mining and Metallurgical Research Institute Ji Jun used the combination of CaCI: and lime to get rid of the activation of arsenic pyrite by Cu2+ and realize the separation of arsenic pyrite and polymetallic sulphide in neutral and weakly alkaline pulp. In the case of arsenic up to 5.17% in the ore, the arsenic content in lead and zinc concentrates decreased to 0.44% and 0.35%, respectively. (3) oxidant type inhibitors. The poisonous sand is relatively easy to oxidize, and stirring for a long time or adding various oxidants can strongly suppress the floatability of the arsenopyrite. Many types oxidizing agent, commonly potassium permanganate, hydrogen peroxide, manganese dioxide, bleaching powder, potassium peroxodisulfate (K2S2O8), sodium hypochlorite, and potassium chromium weight. The use of hydrogen peroxide or sodium hypochlorite as an oxidation inhibitor inhibits pre-activated arsenopyrite. It is found that when the pH is greater than 7, the inhibitory effect of oxidant on arsenopyrite is enhanced, and the strong oxidant can inhibit the pre-flotation of arsenic yellow iron. mine. Under acidic conditions, when potassium permanganate is used as the oxidant, the sodium dodecyl sulfonate is used to float the gold-containing arsenopyrite from the mixed concentrate of pyrite and arsenopyrite with good effect. MJV Beattie and other hydrogen peroxide or sodium hypochlorite as oxidant inhibitors, using sodium hydroxide as a regulator, resulting in the oxidation of the surface of arsenic pyrite to form a hydroxide film of iron, thereby inhibiting its floatability, achieving the arsenic yellow iron Separation of the mine. In addition, increasing the temperature of the slurry accelerates the oxidation process. A large number of experimental work has shown that the control temperature is 40-50 ° C, which can strengthen the inhibition of arsenopyrite. (4) A carbonate type inhibitor. It mainly includes sodium carbonate and zinc carbonate. Using sodium carbonate as an inhibitor, it has a certain cleaning effect (dissolution) on the oxidation products of the surface of the sulfide ore such as pyrite, thereby activating the sulfide ore such as pyrite, and increasing the floatability of the sulfide ore and the arsenic mineral. Large, greatly enhanced the effect of separation. What works for zinc carbonate is actually colloidal zinc carbonate. Ming Jingfan and other discoveries: When zinc sulfate and sodium carbonate are mixed in a certain ratio to form colloidal zinc carbonate as an inhibitor, satisfactory effects of suppressing arsenopyrite can be obtained. Zhu Shenhong also found that no matter the ratio of sodium carbonate and zinc sulfate, there is no effect on the flotation of golden iron ore, and it is found that the proper ratio of sodium carbonate and zinc sulfate should be suitable below 30.00% of zinc sulfate. Li Guangming and other combined use of sodium carbonate and bleaching powder found that it can strengthen the inhibition of poisonous sand, and properly control the order of addition of the agent, which can improve or activate the flotation of pyrite. (5) Sulfur oxide inhibitors. There have been many reports on the application of sulphur oxide compounds to arsenic inhibition, and they have also been applied in industry. Such agents mainly include sodium sulfite, thiosulfate, sodium sulfide, potassium peroxydisulfate, and phosphorus pentasulfide + sodium hydroxide. Sodium sulfite is an inexpensive and effective inorganic modifier commonly used in the separation of pyrite and arsenopyrite, which can effectively inhibit arsenic. Studies have shown that the use of potassium peroxodisulfate oxidant to inhibit arsenopyrite is much better than the treatment of arsenopyrite with a large amount of lime or an alkaline medium in lime. Zhu Shenhong et al. found that potassium peroxodisulfate was used as an inhibitor in the separation of gold-bearing iron ore and arsenopyrite by oxidation. The oxidation capacity was moderate, the selectivity was strong, and the separation flotation was not affected by the oxidation time. The separation of the two minerals is achieved. Luo Xiaohua achieved fine suppression of toxic sand by sodium sulfite by finely grinding copper sulfide containing toxic sand as the main arsenic mineral and re-grinding the coarse concentrate, and improved the effect of arsenic removal. (6) Research on organic inhibitors. Organic agents are inexpensive and environmentally friendly, and research used as inhibitors is increasingly valued by mineralists. For example, dextrin, sodium humate (ammonium), tannin, polyacrylamide, lignosulfonate and The mixed materials have been applied in the removal of arsenic from sulfide ore, and have achieved satisfactory results, demonstrating the beautiful application prospects of organic inhibitors. At the same time, it has been found that the combination of an organic inhibitor and an inorganic inhibitor is more effective. Liu Siqing used the combination of baking gum and sodium sulfate to inhibit the poisonous sand and obtained a satisfactory gold concentrate. When Wang Xiangying studied the gold-bearing iron ore and arsenopyrite, he applied organic small molecule inhibitors and found that H23 reacted chemically with the surface of the arsenopyrite without cu2+ activation, but did not react with the gold-bearing iron ore. She believed that H23 is a hard base. As a kind of agent, arsenopyrite is a slightly harder acid than gold-containing iron ore. Hard acid has a stronger affinity for alkali, which is the reason why H23 selectively inhibits arsenopyrite.
1.2.3 Other research progress in the separation of arsenic-containing minerals (toxic sand) and (including gold) sulfide ore In recent years, there have been some progress in flotation technology and combined processes. For example, the potential control of flotation of gold-containing arsenic sulfide ore and the replacement of air with nitrogen can accurately control the slurry potential. When gold minerals are flotation, arsenic minerals can be better suppressed. For another example, in the sodium carbonate medium, air is charged to effectively improve the floatability of the arsenopyrite. Matsuoka Lsao et al. used electro-oxidation to remove arsenic from lead-zinc concentrates. It was found that this method is also applicable to the separation of sulfide ore and toxic sand ore such as pyrite and chalcopyrite. AM Abeidu et al. used a magnesium-containing compound as a regulator for the separation of pyrite from chalcopyrite and arsenopyrite, and found that it can selectively inhibit arsenopyrite and chalcopyrite without inhibiting pyrite.
2 Research progress on arsenic removal from arsenic-bearing gold ore. The treatment of arsenic-containing gold ore can be basically classified into two methods: 1 ore with low arsenic content and less gold in arsenopyrite, and arsenic removal by flotation Flotation separation of sulfide ore and arsenopyrite (see Section 1.2 for dearsenication flotation of such arsenic-bearing gold ore, not discussed here); 2 ore with high arsenic and high gold content in arsenopyrite (mostly The arsenic-containing gold ore type is obtained by flotation, and the arsenic-containing gold concentrate is obtained by flotation, and then arsenic is removed according to the corresponding process. 2.1 Research progress in arsenic removal from arsenic-containing refractory gold ore In the field of gold extraction, arsenic-containing refractory gold ore has gradually become the main raw material for gold extraction due to the continuous reduction of easy-to-select gold resources. Statistics show that the development and utilization of arsenic-containing refractory gold mines will become the key to a significant increase in world gold production. Therefore, countries have mentioned important agendas for the recovery of gold in arsenic-containing refractory gold mines. In China, arsenic-bearing gold mines account for a considerable proportion of gold mineral resources. Since the mid-1970s, such gold mines have been discovered in 16 provinces and autonomous regions. Among them, large and medium-sized arsenic gold deposits have been discovered in Hunan, Yunnan, Guizhou, Sichuan, Gansu, Xinjiang and other provinces, but quite a part of them are arsenic-containing fine-grained gold deposits, such as the golden hole in Hunan and the northeastern village in Sichuan. , Danzhai in Guizhou, Pingding and Jiuyuan in Gansu, and Hatu in Xinjiang. Because the gold in this type of arsenic-bearing gold ore (and flotation arsenic-bearing gold concentrate) is microscopic or sub-microscopic gold, the size of the inlay is very fine, and it occurs in the crystal lattice of sulfide ore such as arsenopyrite or pyrite. The mechanical method is difficult to achieve monomer dissociation, and the poisonous sand will cause chemical interference. The direct cyanidation of the whole mud cyanidation or flotation concentrate not only makes the gold leaching rate very low, but also causes the concentrate to contain high arsenic. For the mineralogical characteristics of arsenic-containing refractory gold ore, it can be started from three places: 1 to strengthen or improve the cyanide conditions; 2 to carry out arsenic removal pretreatment; 3 to use non-cyanide method to avoid the disadvantage of substances that interfere with the cyanidation process Effects such as thiosulfate, thiourea, etc. At present, there has been no substantial progress in the study of strengthening or improving the conditions of cyanidation, so all countries are committed to the research of arsenic removal pretreatment and non-cyanide method.
2.2 Research progress on arsenic removal pretreatment of arsenic-containing refractory gold ore (1) Arsenic removal by roasting oxidation. The roasting oxidation method is a widely used arsenic removal method in the industry. At present, the roasting method mainly includes two types of boiling furnace roasting and rotary kiln roasting. The equipment is developed from a single crucible furnace to a multi-hearth furnace, and is developed from a fixed bed roasting to a fluid dynamic boiling roasting until flash roasting. The process progresses from a stage of calcination to two stages of calcination, from air roasting to oxygen enriched roasting. Many scholars have carried out a lot of research on the roasting and arsenic removal method: Xiong Damin and other research on the new roasting technology of high arsenic gold concentrate under protective gas conditions, the arsenic removal rate is 97.32%, and they use carbon disulfide to dissolve sulfur and then The sulfur is recovered, and the arsenic sulfide is reduced by high-purity hydrogen to obtain metal arsenic. The arsenic-containing concentrate of Hunan Golden Cave in China uses a two-stage rotary kiln roasting and arsenic removal process. The process removes arsenic in an oxygen-deficient atmosphere, and the arsenic removal rate is 99.16%. The desulfurization in an aerobic atmosphere yields a cyanide leaching rate of 93%. However, the roasting method emits a certain amount of dust and arsenic dust during the treatment process, and its application will continue to be limited as environmental awareness increases. In the study of bismuth, when potassium peroxodisulfate was used as an inhibitor, its oxidizing ability was moderate, the selectivity was strong, and the separation flotation was not affected by the oxidation time, and the separation of the two minerals could be better achieved. Luo Xiaohua achieved the fine inhibition of toxic sand by sodium sulfite and improved the effect of arsenic removal by finely grinding copper sulfide containing toxic sand as the main arsenic mineral and re-grinding the concentrate. (6) Research on organic inhibitors. Organic agents are inexpensive and environmentally friendly, and research used as inhibitors is increasingly valued by mineralists. For example, dextrin, sodium humate (ammonium), tannin, polyacrylamide, lignosulfonate and The mixed materials have been applied in the removal of arsenic from sulfide ore, and have achieved satisfactory results, demonstrating the beautiful application prospects of organic inhibitors. At the same time, it has been found that the combination of an organic inhibitor and an inorganic inhibitor is more effective. Liu Siqing used the combination of baking gum and sodium sulfate to inhibit the poisonous sand and obtained a satisfactory gold concentrate. Wang Xiangying used organic small molecule inhibitors in the study of gold-bearing iron ore and arsenopyrite. It was found that H23 reacted chemically with the surface of the arsenopyrite without Cu2+ activation, but did not react with the gold-bearing iron ore. Her team was I{23 It is a hard base agent. Arsenopyrite is a slightly harder acid than gold-containing iron ore. Hard acid has a stronger affinity for alkali. This is the reason why H23 selectively inhibits arsenopyrite. 1.2.3 Research progress of arsenic-containing minerals (toxic sand) and (including gold) sulfide ore. In recent years, there have been some progress in flotation technology and combined processes. For example, the potential control of flotation of gold-containing arsenic sulfide ore and the replacement of air with nitrogen can accurately control the slurry potential. When gold minerals are flotation, arsenic minerals can be better suppressed. For another example, in the sodium carbonate medium, air is filled, which can effectively improve the floatability of the arsenopyrite. Matsuoka Lsao et al. used electro-oxidation to remove arsenic from lead-zinc concentrates. It was found that this method is also applicable to the separation of sulfide ore and toxic sand ore such as pyrite and chalcopyrite. AM Abeidu et al. used a magnesium-containing compound as a regulator for the separation of pyrite from chalcopyrite and arsenopyrite, and found that it can selectively inhibit arsenopyrite and chalcopyrite without inhibiting pyrite. 2 Research progress on arsenic removal from arsenic-bearing gold ore. The treatment of arsenic-containing gold ore can be basically classified into two kinds of land: 1 ore with low arsenic content and less gold in arsenopyrite, and arsenic removal by flotation. That is, flotation separation of sulfide ore and arsenopyrite (see Section 1.2 for arsenic-free flotation of such arsenic-containing gold ore, which will not be discussed here); 2 ore with high arsenic I and high gold content in arsenopyrite ( Mostly arsenic-containing refractory ore type), the arsenic-containing gold concentrate is obtained by flotation, and then arsenic is removed according to the corresponding process.
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