混合电镀污泥中铬铁的选择性分离工艺

Selective Separation Technology of Chromium and Ironfrom Mixed Electroplating Sludge

提出了利用磷酸盐从还原预处理后的电镀污泥浸出液中优先分离铬的工艺,并从理论上证明了铬铁分离的可行性,探讨了磷酸钠用量、溶液初始pH、反应温度、保温时间对铬铁分离效果的影响。优化条件为:PO_4^(3-)/Cr^(3+)摩尔比1.1、溶液初始pH 2.0、反应温度80℃、保温时间60 min、搅拌转速400r/min,铬和铁沉淀率分别为96.0%和0.68%,铬铁单级分离系数141.2。

A new process of chromium selective extraction with phosphate from electroplating sludge leaching liquor after reduction pretreatment was proposed. The feasibility was theoretically proved. The effects of sodium phosphate dosage, initial pH value of solution, reaction temperature, and holding time on precipitation rate of chromium and iron were investigated. Precipitation rate of chromium and iron is 96.0% and 0.68% respectively with single-stage separation factor of chromium and iron of 141.2 under the optimum conditions including PO4a-/Cr3＋ =1.1 （tool ratio）, initial pH value of 2.0, reaction temperature of 80 ℃, holding time of 60 min, and stirring speed of 400 r/min.