磷酸浸取黄磷炉渣制沉淀二氧化硅的研究

Study on preparation of precipitated silica by leaching yellow phosphorus slag with phosphoric acid

以工业黄磷生产过程中产生的固体废弃物(黄磷炉渣)为原料,采用磷酸浸出,以磷酸二氢钙的形式分离钙元素,浸取渣经精制、洗涤、煅烧可得到沉淀水合二氧化硅产品。其二氧化硅质量分数可达97%,白度88%,比表面积205 cm2/g,铁、铜、锰等杂质均能达到沉淀水合二氧化硅产品的质量要求,经X射线衍射分析产品为无定形二氧化硅。研究表明,为了得到外观质量合格的产品,样品必须进行煅烧处理。煅烧的最佳工艺条件为:煅烧温度700℃,煅烧时间0.5 h。

With solid waste （yellow phosphorus slag） generated in the production of industrial yellow phosphorus as the raw material and with phosphoric acid as leaching agent, the calcium was separated from the yellow phosphorus slag as the form of calcium biphosphate. After the refining, washing and calcining, the precipitated silica product was obtained, whose mass fraction of silica （ SiO2 ） can reach 97% ,white content was 88%, specific surface area was 205 cm^2/g and the contents of impurities, such as Fe, Cu and Mn etc. all could meet the quality requirements of precipitated silica product. The XRD analysis indicated that the product was amorphous SiO2. The study showed that the sample must be calcined in order to obtain the appearance qualified product. The optimum technical conditions of calcination were ： calcining temperature 700 ℃ and calcining time 0.5 h.