(1. 中南大學(xué) 冶金與環(huán)境學(xué)院，長沙 410083；
2. 湖南城市學(xué)院 市政與測繪工程學(xué)院，益陽 413000；
3. 中南大學(xué) 國家重金屬污染防治工程技術(shù)研究中心，長沙 410083)
摘 要: 以鋅冶煉中浸渣為研究對象，研究中浸渣的化學(xué)成分及鋅的存在形態(tài)，鋅主要以鐵酸鋅形式存在。采用SO2做還原劑，研究溫度、初始硫酸濃度、二氧化硫分壓對鋅浸出效率的影響，并分析中浸渣中鋅還原浸出反應(yīng)機制及動力學(xué)。結(jié)果表明：H+在鋅還原浸出過程中起關(guān)鍵作用，鋅還原浸出反應(yīng)活化能為31.67 kJ/mol，為化學(xué)反應(yīng)控制；SO2做還原劑時，反應(yīng)時間、液固比及初始酸度均大幅降低。反應(yīng)最佳工藝條件：初始硫酸濃度80 g/L、溫度95 ℃、液固比(L/S) 10 mL/g、二氧化硫分壓200 kPa、反應(yīng)時間120 min。該工藝條件下，中浸渣中鋅浸出率達(dá)99%以上。XRD和ICP分析表明：中浸渣中鐵酸鋅分解，硫化鋅在該反應(yīng)條件下未完全浸出，還原浸出渣中主要化學(xué)成分為鉛和鋅，主要物相為PbSO4和ZnS。
關(guān)鍵字: 中浸渣；還原浸出；二氧化硫；動力學(xué)
（1. School of Metallurgy and Environment, Central South University, Changsha 410083, China;
2. School of Municipal and Mapping Engineering, Hunan City University, Yiyang 413000, China;
3. Chinese National Engineering Research Center for Control and Treatment of
Heavy Metal Pollution, Central South University, Changsha 410083, China）
Abstract:The chemical composition and zinc phases were studied by XRD, XPS, ICP and phase analysis. The effects of temperature, initial sulfuric acid concentration and partial pressure of sulfur dioxide on the Zn leaching rate were also studied when sulfur dioxide was used as reductant. The mechanism and kinetics of reductive decomposition of zinc ferrite were also studied. The results show that H+ plays a key role during the reductive leaching process. The activity energy is 31.67 kJ/mol and the kinetic equation is established based on the chemical reaction controlled model. The optimum technological conditions are as follows: initial sulfuric acid concentration 80 g/L; temperature 95 ℃; liquid-to-solid 10; sulfur dioxide partial pressure 200 kPa; reactive time 120 min. Under the optimum condition, zinc leaching efficiency reached more than 99% and the main phase in the reductive residue are lead sulfate and zinc sulfide.
Key words: zinc neutral leaching residue; reductive leaching; sulfur dioxide; kinetics
