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采用焙烧-酸浸-氰化法从某含多金属复杂金精矿中提取金、银、铜,考察了焙烧预处理气氛、温度、时间、氢氧化钠加入量4个因素对金、银、铜提取率的影响。结果显示,焙烧气氛是影响金、银、铜提取率的关键因素,在富氧气氛下焙烧预处理,金、银、铜的提取率有显著提高,并确定较优试验条件为:富氧气氛,焙烧温度903 K,焙烧时间3 h,氢氧化钠加入量4%,硫酸浸出,液固比4∶1,硫酸浓度1 mol·L-1,反应温度363 K,反应时间3 h,氰化浸出,液固比4∶1,pH值10.5,氰化钠浓度4‰,反应72 h,此条件下,金、银、铜的提取率分别为94.55%,83.25%,94.75%。银化学物相分析知,添加氢氧化钠焙烧预处理,能够有效降低硅酸盐包裹银的含量。热力学计算知,在T=903 K,加入氢氧化纳焙烧预处理,可以减小ZnO·Fe2O3,CuO·Fe2O3,2ZnO·SiO2,2PbO·SiO2,PbO·SiO2的生成几率,削弱上述物质对金、银的包裹作用,对比不同氧压下的lgpSO2-lgp O2图,知氧分压越高,硫酸化焙烧稳定区域面积越大,有利于硫酸化焙烧进行,从而可以获得更高的金、银、铜的提取率。
Gold, silver and copper were extracted from a complex gold concentrate containing multimetal by roasting - acid leaching - cyanidation method. The effects of pretreatment atmosphere, temperature, time and adding amount of sodium hydroxide on gold, silver, Effect of copper extraction rate. The results showed that the roasting atmosphere was the key factor affecting the extraction rate of gold, silver and copper. The roasting pretreatment in oxygen-enriched atmosphere significantly improved the extraction rate of gold, silver and copper. The optimum experimental conditions were as follows: oxygen-enriched atmosphere , Calcination temperature 903 K, calcination time 3 h, sodium hydroxide 4%, sulfuric acid leaching, liquid to solid ratio 4: 1, sulfuric acid concentration 1 mol·L-1, reaction temperature 363 K, reaction time 3 h, The results showed that the extraction rates of gold, silver and copper were 94.55%, 83.25% and 94.75% respectively under the conditions of leaching, liquid-solid ratio of 4:1, pH value of 10.5, concentration of sodium cyanide of 4 ‰ and reaction time of 72 h. Silver chemical phase analysis, addition of sodium hydroxide roasting pretreatment, can effectively reduce the silicate-coated silver content. Thermodynamics calculation shows that adding sodium hydroxide calcination pretreatment at T = 903 K can reduce the formation probability of ZnO · Fe2O3, CuO · Fe2O3, 2Nn · SiO2, 2PbO · SiO2, PbO · SiO2 and weaken the formation of gold, Compared with the lgpSO2-lgp O2 at different oxygen pressures, the higher the partial pressure of oxygen, the larger the area of the sulfated baking stable zone is, which is favorable for the sulfation roasting, so as to obtain higher gold, silver, Copper extraction rate.