(昆明理工大學(xué)冶金與能源工程學(xué)院，昆明 650093)
摘 要: 銅冶煉過程產(chǎn)生的煙塵和污酸等危險(xiǎn)廢物的無害化處理及有價(jià)金屬的綜合高效回收是銅冶煉行業(yè)亟待解決的重大環(huán)保問題。本研究采用“以廢制廢”的研究思路，利用污酸中的游離酸實(shí)現(xiàn)銅冶煉煙塵中有價(jià)金屬的高效浸出。開展了銅冶煉煙塵與污酸協(xié)同浸出實(shí)驗(yàn)，深入研究關(guān)鍵宏觀技術(shù)參數(shù)對(duì)銅、砷浸出率以及復(fù)雜砷物相的溶解及沉淀過程礦相轉(zhuǎn)變行為的影響規(guī)律。結(jié)果表明：在反應(yīng)溫度80 ℃、液固比8:1、反應(yīng)時(shí)間1 h、攪拌速度300 r/min、亞硫酸鈉加入劑量為1的浸出條件下，銅浸出率高達(dá)99%，砷浸出率為80%，煙塵中的鉛、銀、鉍等有價(jià)金屬在浸出渣中的富集率達(dá)99%以上。協(xié)同浸出過程中砷酸鉍、砷酸鐵等難溶砷酸鹽的形成，抑制了砷的深度浸出。反應(yīng)溫度對(duì)As(Ⅴ)的還原和As(Ⅲ)的氧化均影響顯著，成為影響砷物相沉淀與溶解的主要因素；當(dāng)浸出溫度低于90 ℃時(shí)，反應(yīng)體系中As(Ⅴ)與Bi(Ⅲ)結(jié)合形成晶型砷酸鉍(BiAsO4)沉淀，且其熱力學(xué)優(yōu)勢(shì)區(qū)隨反應(yīng)溫度的升高而增大；當(dāng)反應(yīng)溫度高于90 ℃時(shí)，As(Ⅴ)還會(huì)與Fe(Ⅲ)結(jié)合形成少量非晶型砷酸鐵(FeAsO4)沉淀，且溫度越高越有利于其形成；縮短反應(yīng)時(shí)間或通過添加亞硫酸鈉(Na2SO3)還原劑降低體系氧化還原電位可抑制砷酸鉍(BiAsO4)的形成。
關(guān)鍵字: 銅冶煉煙塵；污酸；浸出；砷酸鉍；砷酸鐵
（Faculty of Metallurgical and Energy Engineering, Kunming University
of Science and Technology, Kunming 650093, China）
Abstract:The harmless treatment of hazardous wastes, such as dust and waste acid from copper smelting process and comprehensive recovery of valuable metals, are important environmental problems to be solved in copper smelting industry. In this study, the free acid in waste acid was used to high efficiently leaching of valuable metals from copper smelting dust with the ideal of treatment of waste by waste. The collaborative leaching of copper-smelting dust and waste acid was conducted, and the influence of key parameters on the leaching rate of copper and arsenic, and the dissolution, precipitation, and mineral phase transformation behavior of complex arsenic phases were intensively studied. The results show that, under the conditions of reaction temperature of 80 ℃, liquid-solid ratio of 8:1, reaction time of 1 h, stirring speed of 300 r/min, and the equivalent sodium sulfite addition of 1, the leaching rate of copper is as high as 99%, and the leaching rate of arsenic is 80%, and the enrichment rates of lead, silver, bismuth in the leaching slag are more than 99%. Because of the formation of insoluble arsenate, such as bismuth arsenate and iron arsenate in the collaborative leaching process, the efficient leaching of arsenic is inhibited. The reaction temperature has a significant effect on the reduction of As(Ⅴ) and the oxidation of As(Ⅲ), which becomes the main factor affecting the precipitation and dissolution of arsenic. When the leaching temperature is lower than 90 ℃, As(Ⅴ) and Bi(Ⅲ) converte to crystalline bismuth arsenate (BiAsO4), and its thermodynamic advantage zone increases with the increase of the reaction temperature. When the reaction temperature is higher than 90 ℃, As(Ⅴ) and Fe(Ⅲ) form a small amount of amorphous iron arsenate (FeAsO4), and the higher the temperature, the more favorable the formation of amorphous iron arsenate. The system''''s oxidation-reduction potential should be reduced by shortening the reaction time or adding sodium sulfite (Na2SO3) reductant, and it can inhibit the formation of bismuth arsenate (BiAsO4).
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