高锗锌精矿锌锗深度浸出及铁同步沉淀行为

Deep Leaching of Zinc and Germanium from High Germanium Zinc Concentrate and Simultaneous Precipitation of Iron

稀散金属锗是中国战略新兴产业发展的保障性资源之一,在锌冶炼过程中,锗的综合高效回收具有重要意义.开展了高锗锌精矿两段逆流氧压酸浸过程Fe的沉淀机理和Zn、Ge高效浸出行为研究,通过技术参数优化与过程控制同时实现Zn、Ge的深度浸出和Fe的高效沉淀.结果表明:在I段低酸沉铁氧压酸浸过程中,反应温度是影响Fe沉淀的最主要因素,升高反应温度促进了Fe以黄钾铁矾(KFe_(3)(SO_(4))_(2)(OH)_(6))与赤铁矿(Fe_(2)O_(3))形式沉淀,增大初始酸度,促进Zn、Ge的浸出,但对Fe沉淀起抑制作用;在Ⅱ段高温高酸浸出过程中,搅拌转速以及初始酸度的提高,促进了Zn、Ge、Fe的高效浸出,浸出终渣中硫化锌(ZnS)及亚稳态KFe_(3)(SO_(4))_(2)(OH)_(6)物相的逐步消失,浸出终渣物相组成过渡到以单质硫(S~0)为主,氧分压的增大促进了性质相对较为稳定的黄铁矿(FeS_(2))的溶解.在Ⅰ段反应温度110℃、初始酸度58.3 g/L、反应时间120 min、氧分压0.3 MPa、液固比7∶1(mL/g)、搅拌转速600 r/min;Ⅱ段反应温度145℃、初始酸度130 g/L、反应时间120 min、氧分压1.0 MPa、搅拌转速600 r/min的优化技术条件下,高锗锌精矿中Zn、Ge浸出率分别大于99%和96%,得到了含Zn^(2+)145 g/L、Ge 100 mg/L、TFe<2 g/L、H_(2)SO_(4)<5 g/L的低酸低铁I段富锗硫酸锌浸出液,为Ⅰ段浸出液中有价金属Zn、Ge的进一步分离回收以及减少危废铁渣的排放提供了有利条件.

Rare germanium is one of the guarantee resources for the development of China’s strategic emerging industries.The comprehensive and efficient recovery of germanium in zinc smelting process is of great significance.This paper studied the Fe precipitation mechanism and the high-efficiency leaching behavior of Zn and Ge in the two-stage countercurrent oxy-pressure acid leaching process of high germanium zinc concentrate.Through the optimization of technical parameters and process control,the deep leaching of Zn and Ge and the high-efficiency precipitation of Fe were realized at the same time.The results show that in the stage I low-acid precipitation iron oxy-pressure acid leaching process,the reaction temperature is the most important factor affecting Fe precipitation.Increasing the reaction temperature promotes the conversion of Fe to jarosite(KFe_(3)(SO_(4))_(2)(OH)_(6)).And hematite(Fe_(2)O_(3))precipitation,increase the initial acidity and promote the leaching of Zn and Ge,but inhibit Fe precipitation;In the process of high temperature and high acid leaching in stage II,the increase of stirring speed and initial acidity promoted the efficient leaching of Zn,Ge and Fe,the phase of zinc sulphide(ZnS)and metastable KFe_(3)(SO_(4))_(2)(OH)_(6)in the final leaching residue gradually disappeared,the phase composition of the final leaching residue was mainly composed of elemental sulfur(S^(0)),and the increase of oxygen partial pressure promoted the dissolution of relatively stable pyrite(FeS_(2)).Under the optimized technical conditions of stage I,the reaction temperature is 110℃,the initial acidity is 58.3 g/L,the reaction time is 120 min,the oxygen partial pressure is 0.3 MPa,the liquid-solid ratio is 7∶1(mL/g),and the stirring speed is 600 r/min;stage II reaction temperature of 145℃,initial acidity of 130 g/L,reaction time of 120 min,oxygen partial pressure of 1.0 MPa and stirring speed of 600 r/min,the leaching efficiencies of Zn and Ge in high germanium zinc concentrate are more than 99%and 96%respectively.A stage I germanium rich zinc sulfate leaching solution with low acid and low iron containing Zn^(2+)145 g/L、Ge 100 mg/L、TFe<2 g/L、H_(2)SO_(4)<5 g/L is obtained,which is the valuable metal Zn in stage I leaching solution.The further separation and recovery of Ge and the reduction of the discharge of hazardous waste iron slag provide favorable conditions.