用铬浸渣烧硅酸盐水泥解毒的可行性探讨

本文测定了经高温窑炉烧成的铬渣水泥的Cr~(6+)去除率,并从水泥混凝土实际使用情况出发,设计了毒性鉴别方法,分析了整块和破碎的铬渣水泥石水溶性Cr~(6+)的溶出量,观察了大气日晒条件下已还原铬的稳定性.结果表明,经水泥窑煅烧,铬渣水泥的Cr~(6+)去除率达90％以上;当水泥中总Cr_2O_3小于1％时,铬渣水泥石溶出的Cr~(6+)浓度不会超过污水排放标准;当总Cr_2O_3小于0.4％时,水泥石表面的Cr~(6+)溶出量不会超过饮用水标准.铬渣水泥中已被还原的铬在大气、日晒的长期作用下是稳定的.

An Experimental Study on Treatment of Chromic Slag with the Way of Burning for Making Portland Cement

Chrome skg discharged from bichromate plants contains 0.1-0.3% water-soluble Cr6+ and 0.2+0.8% acid-soluble Cr6+, which is a nasty pollutant. This paper presents a new method for treatment of chrome slag containing Cr6+ by means of adding a small amount of it to raw meal for making Portland cement. In the experiments, Cr6+ removal rate of chrome-slag cement burned in a laboratory furnace or a small shaft kiln were obtained, the dissolved amounts of water-soluble Cr6+ from hardened cement cubes or from those mortar were analyzed, and the stability of reduced chrome in cement under weathering was obserbed. The results demonstrate that the removal rate of Cr6+ by "burning is over 90%. If total Cr2O3 in cement is below 1%, the dissolved Cr6+ concentration from the cement will not exceed 0.5 mg/L for sewage. If total Cr2O3 is below 0.4%, the Cr6+ concentration will noe exceed 0.05 mg/L for drinking water. The reduced chrome in hardened cement is stable under a long-term weathering, so the method is feasible for treating chrome slag.