High-temperature reduction of chromium (VI) in solid alkali.
Chromium (VI) that exists in many industrial wastes is considered highly toxic. One of the most common ways to dispose of these wastes is to reduce chromium (VI) to chromium (III), which is less toxic and can be relatively easily removed or fixed. However, the reduction of chromium (VI) is often conducted in acidic solutions and the chromium (VI) in alkaline solid wastes is hardly to be fully removed. The present study describes a new method for reducing chromium (VI) in alkaline solid. By mixing alkaline solids containing chromium (VI) with an aqueous sucrose solution and then calcinating the resulting mixture at 400-600 degrees C in inertial gas, chromium (VI) can be easily reduced to an insoluble chromium oxide. The reduced fraction can reach up to 99% in 10-20 min under the conditions of temperature above 600 degrees C and sucrose/chromium > or = 1 g/1 g.
Wang
Tiangui
T
Institute of Process Engineering, Chinese Academy of Sciences, P.O. Box 353, Beijing 100080, China. tgwang@home.pie.ac.cn
Li
Zuohu
Z
D000468:Alkalies / Q000737:chemistry*; D002857:Chromium / Q000737:chemistry*; D006358:Hot Temperature; D007220:Industrial Waste / Q000517:prevention & control*; D010084:Oxidation-Reduction; D017693:Sodium Bicarbonate / Q000737:chemistry; D013213:Starch / Q000737:chemistry; D013395:Sucrose / Q000737:chemistry; D013696:Temperature
D000468:Alkalies; D007220:Industrial Waste; D002857:Chromium; C074702:chromium hexavalent ion; D013395:Sucrose; D017693:Sodium Bicarbonate; D013213:Starch