A pilot-scale study of cryolite precipitation from high fluoride-containing wastewater in a reaction-separation integrated reactor  

作　　者：Ke Jiang Kanggen Zhou Youcai Yang 

机构地区：[1]Hu Du School of Metallurgical Science and Engineering, Central South University

出　　处：《Journal of Environmental Sciences》2013年第7期1331-1337,共7页环境科学学报（英文版）

基　　金：supported by the Major Science and Technology Program of Hunan(China)(No.2009FJ-1009)

摘　　要：Fluoride removal by traditional precipitation generates huge amounts of a water-rich sludge with low quality, which has no commercial or industrial value. The present study evaluated the feasibility of recovering fluoride as low water content cryolite from industrial fluoride-containing wastewater. A novel pilot-scale reaction-separation integrated reactor was designed. The results showed that the seed retention time in the reactor was prolonged to strengthen the induced crystallization process. The particle size of cryolite increased with increasing seed retention time, which decreased the water content. The recovery rate of cryolite was above 75% under an influent fluoride concentration of 3500 mg/L, a reaction temperature of 50°C, and an influent flow of 40 L/hr. The cryolite products that precipitated from the reactor were small in volume, large in particle size, low in water content, high in crystal purity, and recyclable.Fluoride removal by traditional precipitation generates huge amounts of a water-rich sludge with low quality, which has no commercial or industrial value. The present study evaluated the feasibility of recovering fluoride as low water content cryolite from industrial fluoride-containing wastewater. A novel pilot-scale reaction-separation integrated reactor was designed. The results showed that the seed retention time in the reactor was prolonged to strengthen the induced crystallization process. The particle size of cryolite increased with increasing seed retention time, which decreased the water content. The recovery rate of cryolite was above 75% under an influent fluoride concentration of 3500 mg/L, a reaction temperature of 50°C, and an influent flow of 40 L/hr. The cryolite products that precipitated from the reactor were small in volume, large in particle size, low in water content, high in crystal purity, and recyclable.

关 键 词：fluoride-containing wastewater CRYOLITE CRYSTALLIZATION low water content reaction-separation integrated reactor 

分 类 号：X703[环境科学与工程—环境工程]