基于白碳黑的水化硅酸钙制备及其磷回收特性

Preparation and phosphorus recovery characteristic of calcium silicate hydrate based on white carbon black

以白碳黑、硅灰、硅藻土和硅胶筛选硅质原料,并与钙质原料电石渣制备了水化硅酸钙。借助XRF、BET、FTIR等表征手段,通过多次重复除磷实验,研究了硅质原料特性对水化硅酸钙回收磷性能的影响。结果表明,白碳黑具有极高的反应活性,因此可作为制备具有磷回收特性的水化硅酸钙的硅质原料。结合XRD等表征发现,白碳黑的有效利用率是影响水化硅酸钙回收磷性能的关键,该利用率取决于白碳黑与电石渣的摩尔配比以及水热反应温度。当电石渣与白碳黑的摩尔比为1.6∶1,反应温度为170℃时,白碳黑具有最佳的利用效率。该条件制备的水化硅酸钙可作为晶种,在其表面结晶形成羟基磷灰石,从而达到磷回收的目的,磷回收后固体物质中的磷含量为19.05%。

The carbide residue and siliceous materials （such as silica fume, diatomite white carbon black and silica gel） were used to synthesize calcium silicate hydrate comparatively. The repeated phosphorus removal tests and the effect of the characteristics of siliceous materials on the phosphorus recovery performance of calcium silicate hydrate were studied via XRF, BET and FTIR. The result showed that white carbon black has higher ac- tivity to react with carbide residue, so it is suitable to using as a siliceous material. According to XRD test, ef- fective rate of utilization of white carbon black was the key for phosphorus recovery performance of calcium sili- cate hydrate. This utilization rate was depended on the Ca/Si mole ratio and reaction temperature. The utilization rate reached the best under the conditions of Ca/Si mole ratio of 1.6：1 and reaction temperature of 170℃. Un- der these conditions, phosphorus could be recovered in the form of hydroxyapatite using calcium silicate hydrate as seed crystal. The phosphorus content of solid material was 19.05%.