The Chromium Slag' Detoxification And Its Solidifying

Treatment of the chromium slag has been greatly concerned as the chromium slag's large quantity of producing,reservation and its high toxicity. It has been as an dangerous waste. At presently,the center of dealing with dangerous wastes often treats the chromium slag by solidifying and stuffing safely. But the Cr(VI) in chromium slag is easy to dissolve in the water and hard to deposit. So the leaching toxicity of solidified body often exceeds standard,and has a badly contaminated to environment. This article treats the Cr(VI) of chromium slag firstly,and then analyzes the feasibility of chromium slag using in building material.This paper suggested a simple and economical way using water as the solvent, leaching the Cr(VI) and consequently lowering the toxicity of the chromium slag. Water is used as the solvent for its advantages listed as: simplicity in operation, short process time, good effect of leaching rate. The factors on chromium slag leaching have been analyzed during the tests. And the Cr(VI) was treated in virtue of deoxidization of active carbon. Finally the deoxidized Cr(III) was got back as sediments to realize the recycle of chromium.The results show that a greeable conditions are the chromium slag granularity Liquid / Solid (L/S) 0.25,temperature 60℃,stirring rate 1400rpm,lixiviate time 2h,lixiviate 12 times,the final Cr(VI) lixiviate rate is over 90%.The effects of pH value of waste water, reaction time, addition amount of active carbon, initial consistency of Cr(VI) and temperature on Cr(VI) treatment have been investigated in the test of active carbon treatment. It is shown that the final Cr(VI) lixiviate rate is over 99% when addition amount of active carbon is 0.8g, pH value 2, stirring time 20 min and Cr(VI) consistency 200mg/L.In this paper, the influence of adding treated chromium slag into solidified body on its compressive strength and the influence of different factors on lixiviate consistency and surface lixiviate rate of Cr(VI) in the solid have been studied. It is found that the addition of chromium slag has passive effect on the strength of solidified body. The temperature and pH value both influence the lixiviate of Cr(VI) greatly. But after treatment in any conditions the lixiviate consistency is all less than the prescriptive 1.5 mg/L in GB 5805.3–1996'Dangerous waste discrimination standard - on lixiviate toxicity'. It is proved that even the solidified body as the building material is destroyed,...