黏结剂对硅藻吸附陶粒性能的影响

Effects of Binder on the Properties of Diatomite Ceramsite

在制备以硅藻土为主要原料的吸附陶粒过程中,需加入黏结剂以增强陶粒的力学强度,不同种类黏结剂影响吸附陶粒的吸附性能和力学性能。本试验探究了淀粉、硅酸盐水泥、高岭土、聚乙烯醇和水玻璃等黏结剂对硅藻吸附陶粒吸附性能和力学性能的影响。试验表明,采用水玻璃作为黏结剂,硅藻吸附陶粒具有良好的力学和吸附性能,并且在水玻璃模数为1,添加量为9%,在400℃下焙烧30 min时,可得到对溶液中阳离子红去除率为50.83%,散失率为11.00%的硅藻吸附陶粒。在高温焙烧下,水玻璃中的Na2O成分对硅藻表面具有助熔作用,其中的Si O2成分凝聚形成-Si-O-Si-网络结构,将硅藻颗粒黏结,增强了硅藻吸附陶粒力学强度,同时还保留了丰富的Si-OH吸附位点,吸附能力较高。

Diatom ceramsite was prepared by diatomite and binder which enhanced the mechanical strength of diatom ceramsite. And the effects of portland cement, kaolin, starch, polyvinyl alcohol and sodium silicate as binders on its adsorption and mechanical properties was explored. When sodium silicate was employed as a binder, diatom ceramsite had good mechanical and adsorption properties. The removal rate of diatom ceramsite for Red X-GRL in the solution was 50.83% and its loss rate was 11% when the test conditions were arranged as: addition amount of the sodium silicate was9%, modulus was 1, roasting temperature was 400 ℃ and roasting time was 30 min. The Na2 O component in the sodium silicate can help to melt the ceramsite surface, and the SiO2 condensates the-Si-O-Si-network structure, so that the diatom particles are bonded to enhance the mechanical strength of the diatom ceramsite. Meanwhile, the adsorption capacity of the diatom ceramsite was high, due to the Si-OH adsorption sites were retained.