采用对比方法研究难冶金精矿焙砂和烟尘氰化浸金的差异.结果表明,直接氰化时焙砂和烟尘中金的浸出率分别为85.31%和54.30%.砷、碳含量及其存在形式是导致两者金浸出率差异的主要原因.对于NaOH预处理后氰化浸金,焙砂和烟尘中金的最大浸出率分别为87.70%和58.60%.有害元素的脱除、碱浸预处理过程中金的损失及铁氧化物的阻碍共同决定碱浸预处理后焙砂和烟尘中金的浸出率.经H2SO4预处理后,焙砂和烟尘中金的最大浸出率分别达到94.96%和80.40%.碳质物的影响是焙砂和烟尘中金浸出率差异的主要原因.基于这些差异,提出两种适宜工艺,焙砂和烟尘中金的浸出率分别达到94.91%和91.90%.
Differences of cyanide leaching between the calcine and the dust from a refractory gold concentrate were investigated by comparative method. Results showed that gold leaching efficiencies of the calcine and the dust were 85.31% and 54.30%, respectively, with direct cyanidation. Contents and existing forms of arsenic and carbon were the main reasons for those differences. The maximum gold leaching efficiencies of the calcine and the dust were 87.70% and 58.60%, respectively, with cyanidation after NaOH pre-leaching. Harmful elements removal, gold loss in NaOH pre-leaching and iron oxides hindrance codetermined gold leaching efficiencies of the calcine and the dust. After H2SO4 pre-leaching, the maximum gold leaching efficiencies of the calcine and the dust achieved 94.96% and 80.40%, respectively. The effect of carbonaceous matter was the main reason for differences for leaching efficiencies of the calcine and the dust. Based on those differences, two proper gold extraction processes were put forward, and gold leaching efficiencies for the calcine and the dust achieved 94.91% and 91.90%, respectively.