硫铁矿制酸过程的废稀酸中砷及重金属去除研究

Removal of arsenic and heavy metals in waste dilute acid from purification process during sulfuric acid production by pyrite

以硫铁矿制酸过程所产生的酸性废水为研究对象,探讨了硫化剂-铁盐法去除该类酸性废水中砷及重金属元素的最佳工艺条件。结果显示,在硫化钠投加量为1.2 g/L、PFS投加量为0.8 g/L、p H值为2-3的条件下,经过静置、沉淀、过滤处理后,酸性废水中As、Pb、Cd、Cr、Hg的质量浓度分别降至0.310、0.270、0.001、0.004、0.012 mg/L,去除率依次为99.91%、96.78%、97.86%、97.02%、93.15%,处理后酸性废水的p H值仍能够保持在2.5-3.5,可回用于磷肥的工业生产中。该方法产生沉淀污泥量少,且能够有效避免二次污染,实现硫酸工业酸性废水的无害化、资源化和减量化。

Taking the acid wastewater from purification process during sulfuric acid production by pyrite as the research object, the optimal technological condition for sulfurizing reagent-ferric salt method removing arsenic and heavy metals from the said kind of acid wastewater was discussed. The results showed that, under the condition that the dosage of sodium sulphide and PFS were 1.2 and 0.8 g/L respectively, the pH value was 2-3,with the treatment of stewing, sedimentation and filtration, the mass concentrations of As, Pb, Cd, Cr and Hg in the acid wastewater decreased to 0.310, 0.270, 0.001, 0.004 and 0.012 mg/L respectively, and the removal rates were 99.91%, 96.78%, 97.86%, 97.02% and 93.15% respectively. The p H value of the treated acid wastewater maintained at 2.5-3.5, which could be reused in phosphate fertilizer production. The said method produced less precipitation sludge, which could effectively avoid secondary pollution and achieve the goal of ensuring acid wastewater from sulfuric acid industry be harmless, recycling and reducing.