(1. 昆明理工大學(xué) 冶金與能源工程學(xué)院，昆明 650093；
2. 云南馳宏資源綜合利用有限公司，曲靖 655000)
摘 要: 針對(duì)鋅浸出渣處理過程中存在有價(jià)金屬回收率低、危廢鐵渣量大等關(guān)鍵技術(shù)難題，本文提出了鋅浸出渣Ⅰ段控鐵低酸加壓浸出-Ⅱ段深度高酸加壓浸出的兩段逆流加壓酸浸工藝路線。以某濕法煉鋅企業(yè)產(chǎn)出的含鍺鋅浸出渣為研究對(duì)象，重點(diǎn)研究了Ⅰ段控鐵加壓低酸浸出過程中鋅、鍺、鐵的浸出行為，鐵的高溫水解沉淀行為以及鐵物相演變規(guī)律。結(jié)果表明：溫度是影響鐵高效沉淀與鐵物相組成的關(guān)鍵因素，升高溫度能促進(jìn)Fe3+水解生成鐵礬(MFe3(SO4)2(OH)6)，并有利于鐵酸鹽(MeFe2O4)的溶解。降低初始酸度、延長(zhǎng)反應(yīng)時(shí)間均有利于鐵礬晶體的發(fā)育長(zhǎng)大；在高酸體系下，鐵礬的熱力學(xué)穩(wěn)定性降低，且不利于Fe3+的水解沉淀，但通過升高反應(yīng)溫度可使Fe3+水解生成鐵礬和赤鐵礦(Fe2O3)等沉鐵物相，達(dá)到鐵高效沉淀分離的目的；因鋅浸出渣中鐵主要以Fe3+形式存在，故氧分壓對(duì)Ⅰ段浸出過程中鐵的沉淀分離影響不顯著。在反應(yīng)溫度140 ℃、初始酸度46 g/L、反應(yīng)時(shí)間180 min、氧分壓0.3 MPa、液固比6 mL/g、攪拌轉(zhuǎn)速500 r/min的Ⅰ段控鐵低酸加壓浸出優(yōu)化條件下，約90%以上的鐵水解沉淀為鐵礬，獲得了鐵濃度僅為1.88 g/L的Ⅰ段浸出液，為Ⅰ段浸出液中有價(jià)金屬的進(jìn)一步分離提取提供有利條件。經(jīng)Ⅱ段深度高酸加壓浸出后，鋅、銅、鍺的兩段總浸出率分別為96.24%、94.73%、68.76%，含鍺鋅浸出渣的兩段逆流加壓酸浸工藝可同時(shí)實(shí)現(xiàn)鋅、鐵高效分離與鋅、銅、鍺等有價(jià)金屬的高效浸出。
關(guān)鍵字: 含鍺鋅浸出渣；加壓酸浸；浸出率；水解沉鐵；鐵礬
（1. Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China;
2. Yunnan Chihong Resources Comprehensive Utilization Co., Ltd., Qujing 655000, China）
Abstract:Given the critical technical issues in the treatment of zinc leaching residue, such as low metal recovery and a large amount of hazardous waste iron residue, this paper proposes a two-stage countercurrent pressure acid leaching process route for zinc leaching residue, consisting of Ⅰ-stage iron-controlled low acid pressure leaching and Ⅱ-stage deep high acid pressure leaching. Taking the germanium containing zinc leaching residue produced by a zinc hydrometallurgy enterprise as the research object, the leaching behaviors of Zn, Ge, and Fe, the high-temperature hydrolysis precipitation behavior of iron, and the evolution law of the iron phase in the process of iron-controlled pressurized low acid leaching in stageⅠwere studied. The results show that temperature is the key factor affecting the efficient precipitation of iron and the composition of the iron phase. Increasing the temperature can promote the hydrolysis of Fe3+ to form jarosite (MeFe3(SO4)2(OH)6) and is conducive to the dissolution of ferrite (MeFe2O4). Reducing the initial acidity and prolonging the reaction time are conducive to the development and growth of jarosite crystals. In the high-acid system, the thermodynamic stability of jarosite decreases and is not conducive to the hydrolysis and precipitation of Fe3+. However, by increasing the reaction temperature, Fe3+ can be hydrolyzed to form iron precipitation phases such as jarosite and hematite (Fe2O3), so as to achieve the purpose of efficient precipitation and separation of iron; Because iron in zinc leaching residue is mostly in the form of Fe3+, the effect of oxygen partial pressure on iron precipitation and separation in Ⅰ-stage leaching is negligible. Under the optimized conditions ofⅠ-stage iron-controlled low acid pressure leaching with a reaction temperature of 140 ℃, initial acidity of 46 g/L, a reaction time of 180 min, oxygen partial pressure of 0.3 MPa, a liquid-to-solid ratio of 6 mL/g, and stirring speed of 500 r/min, more than 90% of the iron is hydrolyzed and precipitated into alum, and the Ⅰ-stage leaching solution with an iron concentration of only 1.88 g/L is obtained, which provide favorable conditions for the further separation and extraction of valuable metals from the leaching solution. After the Ⅱ-stage of deep high-acid pressure leaching, the total leaching rates of the two stages of zinc, copper, and germanium are 96.24%, 94.73%, and 68.76%, respectively. The two-stage countercurrent pressure acid leaching process of the germanium containing zinc leaching residue can be realized at the same time. With the high-efficiency separation of zinc and iron and high-efficiency leaching of valuable metals such as zinc, copper, and germanium under high-acid pressure leaching, the total leaching rates of the two stages of zinc, copper, and germanium are 96.24%, 94.73%, and 68.76%, respectively. The two-stage countercurrent pressure acid leaching process of the germanium containing zinc leaching residue can be realized at the same time for high-efficiency separation of zinc and iron and high-efficiency leaching of valuable metals such as zinc, copper, and germanium.
Key words: the germanium zinc leaching residue; pressurized acid leaching; leaching rate; hydrolyzed iron precipitation; jarosite
