熔盐法从铁尾矿中制取高纯白炭黑

以铁尾矿和NaOH为原料、NaNO₃为熔盐，在500℃下煅烧3 h，使铁尾矿中的惰性SiO₂转变成活性的硅酸钠相。以浸取硅酸钠溶液作为硅源，利用化学沉淀法成功制备了无定形白炭黑。用X射线衍射仪、红外光谱仪、透射电镜和X射线荧光光谱仪对制取白炭黑的物相结构、粒度形貌和成分含量进行分析。结果表明：白炭黑产品中的SiO₂纯度为99.3%，化学结构为无定形的水合二氧化硅，形貌近似为球状粒子，粒径在100 nm左右。白炭黑的比表面积 (BET)为152 m² •g^-1。

Preparation of high purity precipitated silica from iron ore tailings by molten salt method

The iron ore tailings were mixed with NaOH-NaNO₃ and calcined at 500℃ for 3 h to produce soluble sodium silicate.The iron ore tailings and NaOH were used as raw materials, and NaNO₃ was used as molten salt.The precipitated silica particle was prepared by using sodium silicate as a source of silicon by the chemical precipitation method.The composition, morphology and structure of the synthesized particles were characterized by X-ray diffraction (XRD), FTIR analysis, transmission electron microscopy (TEM) analysis, and X-ray fluorescence analysis (XRF).The SiO₂ purity in the precipitated silica product was 99.3% by XRF.The chemical structure of precipitated silica was hydrated silicon oxide by FTIR analysis.The structure of precipitated silica was amorphous by XRD analysis.The TEM micrograph showed that the shape of precipitated silica particles was nearly spherical, and the average grain diameter was about 100 nm.The specific surface area was 152 m² •g^-1 by the BET method.