生物冶金过程中黄钾铁矾的生成与抑制

Formation and Inhibition of Jarosite in Biohydrometallurgy Process

研究初始pH梯度对细菌培养过程中黄钾铁矾生成的影响。结果表明,黄钾铁矾的生成受溶液pH、细菌活性和Fe^3＋浓度共同影响。溶液pH 1.4-2.0时细菌活性较好,溶液中Fe^2＋转化成Fe^3＋的速率快,促进Fe^3＋水解生成黄钾铁矾;溶液pH 1.0-1.4时Fe^3＋的水解反应受到显著抑制。Fe^3＋的水解过程是先生成胶体相Fe（OH）3后逐渐形核、生长、结晶出黄钾铁矾。生物冶金过程中反应前期溶液pH应大于1.4,此阶段以促进细菌生长、加快矿石氧化分解为主,当细菌生长进入对数期后,溶液pH应小于1.4,此阶段以控制浸出液中细菌的活性,抑制黄钾铁矾的生成为主。

The effects of initial pH value on formation of jarosite in cultivation process of bacteria in shaking flasks were studied. The results show that formation of jarosite is controlled by pH value of solution, bacteria activity and concentration of Fe^3＋. Bacteria have good activity, oxidizing ratio of ferrous ion is high, and generation of jarosite is promoted in the range of 1.4-2.0 pH value. The generation of jarosite is inhibited in the range of 1.0-1.4 pH value. Jarosite is crystallized when Fe（OH）3 as colloid phase is produced in the process of ferric ion hydrolysis. In biohydrometallurgy process, pH value is 1.4 above to accelerate growth of bacteria and oxygenolysis of ore. In bacteria growth logarithmic phase, pH value is 1.4 below to control activity of bacteria in lixivium and depress production of Fe（OH）3.