制革含铬污泥中铬的“酸浸-氧化”回收方法研究

Study on recovery method of chromium from tannery chromium sludge by"acid leaching-oxidation"

以制革含铬污泥为对象,采用硫酸-柠檬酸为浸提剂,重铬酸钾-双氧水为氧化剂,进行铬回收研究.结果表明,硫酸浓度0.5 mol/L、柠檬酸浓度0.1 mol/L、固液比1∶30、浸提时间4 h时,Cr浸提率达88.82%,浸提液内Cr浓度1650 mg/L.氧化处理浸提液,1+3硫酸用量为10%,重铬酸钾固体用量为0.4%,30%双氧水用量为15%时,浸提液内总有机碳(TOC)去除率达78.08%.制革含铬污泥经过酸浸及浸提液氧化处理,浸提液Cr浓度3050 mg/L,TOC浓度由804 mg/L降低至176 mg/L,符合鞣制工艺要求,可直接回用于鞣制工艺,同时污泥减量35%,剩余铬处于稳定态,实现了污泥减量及无害化.

Chromium recovery from tannery chromium sludge was studied using H2SO4-citric acid as extractant and K2Cr2O7-H2O2 as oxidant.The results showed that when the concentration of H2SO4 was 0.5 mol/L,the concentration of citric acid was 0.1 mol/L,the solid-liquid ratio was 1∶30 and the extraction time was 4 h,the extraction rate of Cr was 88.82%,and the concentration of Cr in the extraction solution was 1650 mg/L.Total organic carbon(TOC)removal rate reached 78.08%when the amount of 1+3H2SO4 was 10%,K2Cr2O7 solid was 0.4%and 30%H2O2 was 15%.After acid leaching and oxidation of leaching solution,the concentration of Cr in leaching solution was 3050 mg/L,and the concentration of TOC was reduced from 804 mg/L to 176 mg/L,which met the requirements of tanning process and could be directly reused for tanning process.The sludge was reduced by 35%,and the residual chromium was stable,thus realizing sludge reduction and harmlessness.