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In-situ Oxidative Arsenic Precipitation as Scorodite during Carbon Catalyzed Enargite Leaching Process
Journal of Hazardous Materials ( IF 12.2 ) Pub Date : 2018-08-16 , DOI: 10.1016/j.jhazmat.2018.08.019
Fazel G. Jahromi , Ahmad Ghahreman

This study explores the in-situ precipitation of scorodite (FeAsO4.2H2O) during the atmospheric enargite leaching in acid chloride media. The temperature, oxygen sparging rate and the different fractions of the catalyst and ferric ions were the effective parameters on the scorodite precipitation process. Crystalline scorodite was precipitated out of the leach solution in the absence of seed at temperatures above 80 °C where the ratio of both AF5 to concentrate and activated carbon (AC) to concentrate were 1:2 and 1:1, respectively. The minimal dosage of ferric ions to form the scorodite residue was 5 g/L. Seed addition facilitated the scorodite precipitation process where the primary scorodite particles precipitated after 6 h of enargite leaching. It was shown that via the residual concertation of the arsenic in the pregnant leach solution can be reduced as low as <50 mg/L. A series of the toxicity characteristic leaching procedure (TCLP) tests on the generated scorodite exhibited a low arsenic release ranging from 0.2 to 0.7 mg/L, showing an acceptable stability of the scorodite residue.



中文翻译:

碳催化的凹凸棒石浸出过程中原位氧化砷沉淀为臭葱石

本研究探讨臭葱石的原位沉淀(FeAsO 4 ·2H 2O)在大气中的辉石在酰氯介质中的浸出。温度,氧气喷射速率以及催化剂和三价铁离子的不同馏分是臭葱石沉淀过程的有效参数。在没有晶种的情况下,在高于80°C的温度下,结晶臭葱石从浸出溶液中沉淀出来,其中AF5与精矿的比率以及活性炭(AC)的比率分别为1:2和1:1。形成臭葱石残留物的最低铁离子剂量为5 g / L。种子的添加促进了臭葱石的沉淀过程,在该过程中,钙锌矿浸出6小时后,主要臭葱石颗粒沉淀出来。结果表明,通过在浸出溶液中残留的砷的协同作用,可以将其降低至<50 mg / L。

更新日期:2018-08-17
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