High- copper , high- lead gold concentrate is a difficult type of gold concentrate. For this type of concentrate, if it is leached by direct cyanidation, the cyanide leaching rate of gold and silver is lower and the cost is higher; if it is leached by roasting cyanidation, it is calcined due to high lead content. A large amount of lead sulfate is formed in the process, which causes secondary encapsulation of gold, which affects the cyanide leaching rate of gold. On the basis of the literature, the process of extracting gold and silver by direct cyanidation from such high-copper and high-lead gold concentrates was studied. The test results show that in the cyanidation leaching, CaO+NH 4 HCO 3 is used as the pH adjuster, and the SD leaching agent is added at the same time, which can effectively improve the cyanidation leaching rate of gold and silver. Lead, sulphur and copper of cyanide tailings are recovered by flotation method and roasting-acid leaching method respectively, realizing the comprehensive utilization of valuable elements in gold concentrate. The process is simple in operation, does not increase investment, has low cost, and has significant economic and social benefits. First, the nature of the sample High-copper, high-lead gold concentrates are supplied by a gold mine. The fineness of the ore sample - 200 mesh content is higher than 80%, showing a dark brown color. Main minerals pyrite, chalcopyrite, galena and other sulfide minerals. Gold and silver are mainly present in the above minerals in the form of smear particles and secondary particles, and are encapsulated by sulfides. The main component analysis results of the ore samples are shown in Table 1. Table 1 Analysis results of main components of the ore sample ingredient Au Ag Cu Pb Zn S As W B /% 39.75 193.2 2.72 7.82 0.28 25.80 0.084 It can be seen from Table 1 that the content of copper, lead and sulfur in the gold concentrate is high, especially in copper and lead. Their presence seriously affects the cyanide leaching of gold and silver. Therefore, the ore sample is a gold concentrate containing high copper and high lead refractory type. Second, the conventional cyanide leaching test Weigh a certain amount of gold concentrate in the electric stirring tank and leaching according to the following cyanide leaching conditions: sodium cyanide mass fraction is 0.5%; liquid-solid ratio 2:1; leachate pH>11 (adjusted with CaO); leaching time 48h. The test results are shown in Table 2. Table 2 Direct cyanidation leaching results project Au Ag Raw ore grade / (g·t -1 ) 39.75 193.2 Cyanide grade / (g·t -1 ) 7.5 156.8 Leach rate /% 81.13 18.84 It can be seen from Table 2 that the cyanidation leaching rate of gold and silver is very low according to the conventional cyanidation method, which is 81.13% and 18.84%, respectively. The main reason is that the content of Cu and Pb in gold concentrate is high. The presence of copper not only consumes a large amount of cyanide, but also affects the cyanide leaching of Au and Ag. The dissolved copper may form a CuCN film and a copper film on the surface of Au and Ag minerals, which will passivate and slow down the Au and Ag. Cyanide rate. In addition, the presence of lead sulfide, when the content is less than 1%, does not hinder or even facilitate the cyanidation of gold; but when the lead in the gold concentrate is more than 1%, the gold leaching rate is lowered, and the consumption of sodium cyanide is increased. And lead may form precipitates with S 2 - in the slurry, adhere to the surface of the gold mineral, form a passivation film, and affect the leaching of gold. Third, the use of a new mixed regulator and assisted cyanide leaching test According to the "New Synthetic Conditioner Technology in Roasting Cyanide Process" (Patent No. 01103128.X), two types of pH adjusters, CaO+NH 4 HCO 3 and NOH+NH 4 HCO 3 , are used to concentrate high-copper and high-lead gold concentrates. A cyanide leaching test was carried out. Test conditions: sodium cyanide mass fraction 0.4%; liquid-solid ratio 2:1; leaching time 48h; NH 4 HCO 3 addition amount is 1% of the ore sample; pH ≈10 of the leaching solution was adjusted with CaO and NaOH, respectively. The test results are shown in Table 3. Table 3 using new regulator cyanide leaching results project CaO+NH 4 HCO 3 NaOH+NH 4 HCO 3 Au Ag Au Ag Raw ore grade / (g·t -1 ) 39.75 193.2 39.75 193.2 Cyanide grade / (g·t -1 ) 1.60 118.40 2.00 100.6 Leach rate /% 95.97 38.72 94.97 47.93 It can be seen from Table 3 that cyanide leaching is carried out using CaO+NH 4 HCO 3 as a pH adjuster, and the gold leaching rate is high, but the silver cyanide leaching rate is slightly lower. Compared with the two kinds of adjusting agents, the CaO+NH 4 HCO 3 adjusting agent is used for protecting the alkali, and the cost is low and the benefit is large. Therefore, the CaO+NH 4 HCO 3 adjusting agent is used as the protective base for cyanidation leaching in the production. When the Cyanide leaching is carried out by using the CaO+NH 4 HCO 3 adjusting agent, the SD leaching agent is added to further increase the cyanidation leaching rate of Au and Ag. The amount of SD infusion added is 1% of the amount of the ore sample. The test results are shown in Table 4. Table 4 Addition of SD leaching agent cyanide leaching results project Au Ag Raw ore grade / (g·t -1 ) 39.73 193.2 Cyanide grade / (g·t -1 ) 1.20 98.00 Leach rate /% 96.98 49.28 It can be seen from Table 4 that the cyanidation leaching rates of Au and Ag are 96.98% and 49.28%, respectively, which are increased by 1.01% and 10.56%, respectively, compared with the cyanide leaching without SD aid, and the effect is very obvious. Fourth, to improve the mechanism of gold and silver cyanide leaching rate Literature [1] proposed that ammonium bicarbonate is a weakly basic compound that is easily soluble in water. NH 4 HCO 3 is added to the cyanide leaching pulp. In addition to the role of cyanidation to protect alkali, it is also in the slurry. Harmful elements produce a series of chemical reactions. When the copper in the slurry is high, part of the copper will be dissolved into the solution and form a copper cyanide complex with CN - and OH - in the slurry. The reaction formula is as follows: 2Cu 2 + +7CN - +2OH - →2Cu(CN) 3 2- +CNO - +H 2 O When an ammonia compound is added to the cyanide slurry, a mixed coordination ion [Cu(CN) 3 ·(NH 3 ) 3 ] 2 - is formed , and the mixed coordination ion has a strong gold-soluble ability. The reaction formula is as follows: 4Au0+4[Cu(CN) 3 ·(NH 3 ) 3 ] 2 - +O 2 +2H 2 O→4Cu(CN) 2 - +4Cu(CN)+12NH 3 +4OH - Therefore, in the cyanidation leaching, the addition of ammonium hydrogencarbonate to the copper-containing ore can not only increase the leaching rate of gold, but also reduce the amount of sodium cyanide. Literature [2] pointed out that when the lead content in gold concentrate is less than 1%, it does not affect or even facilitate the leaching of gold. When the lead content is more than 1%, the cyanidation leaching of gold can be reduced, and the amount of sodium cyanide is increased. . For high-lead gold concentrates, when carbonate is introduced, lead can be present in the form of carbonate, which reduces the influence of lead on cyanide leaching, thus adding ammonium bicarbonate for high-lead gold concentrate cyanide. Immersion gold is advantageous. The literature [3] pointed out that in the gold concentrate, there is usually one amount of pyrrhotite. The pyrrhotite contains a soluble stream. When cyanide leaching, it is easy to form a large amount of compounds composed of SO 4 2 - , SCN - etc., which consumes a large amount of oxygen and CN - due to oxygen and cyanide in the solution. Decrease, directly affecting the leaching rate of gold. Further, since the sulfide is dissolved, the passivation film may form a sulfide, arsenic compound and the iron compound on the surface of the gold minerals. The addition of SD leaching agent to the cyanide slurry can serve as a passivation film for oxygen supply and removal of gold mineral surface, which is favorable for cyanide leaching of gold. 5. Comprehensive recycling of cyanide residue After high-copper and high-lead gold concentrates are cyanidated gold and silver, the cyanide-leaching slag contains valuable elements such as Cu, Pb and S, which can be comprehensively recycled according to the process shown in Figure 1. Figure 1 Process of comprehensive utilization of cyanide slag The production practice shows that the above process is feasible, and the valuable elements in the cyanate residue are recycled, and the economic and social benefits are very significant. Conclusion (I) Experimental studies have shown that for high-copper and high-lead gold concentrates, the Cyanide leaching rate of gold and silver can be effectively improved by using CaO+NH 4 HCO 3 adjusting agent and adding SD leaching agent for cyanidation leaching. Compared with the conventional cyanidation method, the cyanidation leaching rates of gold and silver increased by 15.85% and 30.44%, respectively. (2) The production practice shows that the tailings after gold and silver are leached by cyanidation, the lead is selected by flotation, the roasting-acid leaching method is used to recover S and Cu, and the acid leaching residue is used to prepare cement, and all the groups of gold concentrate are realized. Recycling of points. (3) The process is simple and easy to operate, and has low cost. It has been promoted and applied in domestic gold mines and smelting departments, and has achieved good economic and social effects. references: [2] Lu Keyuan, Yu Hong. Lead-free technology for low-lead gold ore, new progress in China's gold mining research [M]. Beijing: Metallurgical Industry Press, 1996. [3] Xue Guang, Yu Yongjiang. Experimental study on increasing the cyanide leaching rate of high sulfur gold concentrate gold [J]. 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[1] Xue Guang, Yu Yongjiang. Technical method for adopting new synthetic modifier in roasting cyanidation process [P]. Chinese patent, O1103128.X.