高岭土负载钛制备具有光催化活性矿物掺合料的研究

Investigation on the preparation of metakaolin-supported titanium mineral admixture with photocatalytic activity

将溶胶-凝胶法制备的钛溶胶负载到硫铁矿尾矿上,采用一步煅烧法把尾矿转化为具有一定火山灰活性和光催化性的负载钛偏高岭土,并用它作为掺合料掺加到了水泥基体中。研究了负载时间、煅烧制度及负载钛量对该掺合料对水泥基材料的力学性能、早期水化行为及光催化性能的影响。结果表明,最佳负载时间为2h,最佳煅烧制度是750℃×2h,TiO2的晶型为结晶度较好的锐钛矿型。掺入水泥中最佳掺量为15%,7d活性指数达到113%,此时水化热低。高岭土中最佳负载钛量为7.5%,此时,0.3g掺合料光照10h对100mL的15mg/L MB的光催化降解率可以达到93.5%以上,将其加入至水泥基中也同样具有良好的光催化自清洁效果。

A new process for preparing metakaolin-supported titania with the feature of both photocatalytic and pozzolanic activity by so called single calcination method was investigated. The ground pyrite tailing was mixed with the titania sol by sol-gel method firstly and then calcining the mixture with the optimum calcination regime by which could turn the kaolin into metakaolin-supported titania which has both good pozzolanic activity and photocatalytic performance. The effect of metakaolin-supported titania mineral admixture＇s dosage, load time on the of cement slurry has been investigated. The results show that the optimum calcination regime was 750 ℃ for 2 hl the optimum loading time was 2 hl the optimum mineral admixture＇s dosage was 15%. The 7 d pozzo- lanic activity index of the metakaolin-supported titania mineral admixture can reach up to 113%0. The photocata- lytic degradation efficiency on the MB of the admixture was high up to 93.5% with the initial concentration of the MB was 15 mg/L. Micro-analysis was examined by XRD, ABS and TAM. The crystal form of titania sup- ported on the metakaolin powder was anatase and had a good crystallinity. The metakaolin-supported titania mineral admixture fabricated by this method demonstrates both a good photocatalytic, self-cleaning effect and excellent pozzolanic activity while incorporating into cementitious materials.