铝土矿尾矿除杂及合成刚玉-莫来石研究

Synthesis of corundum-mullite composites from impurity-removed bauxite tailings

为了开发铝土矿尾矿利用的新途径,采用低钙烧结法对铝土矿尾矿进行除杂处理,然后制备刚玉-莫来石耐火材料,主要研究了铝土矿尾矿-氢氧化钠-碳酸钙混合料的钙比(n(CaO)/[n(SiO_2)+n(TiO_2)])、碱比([n(Na_2O)+n(K_2O)]/[n(Al2O3)+n(SiO_2)+n(Fe_2O_3)])和煅烧温度(950~1 250℃)对杂质去除效果的影响,以及在用除杂后的铝土矿尾矿合成刚玉-莫来石材料时合成温度(1 300~1 500℃)对合成材料物相组成的影响。结果表明:1)低钙烧结法除杂的最佳条件是钙比、碱比均为1.0,在1 150℃保温2 h烧结;经最佳条件烧结后,熟料中Al_2O_3的溶出率为88.40%,SiO_2、Fe_2O_3、TiO_2的去除率分别为59.02%、98.65%、98.57%。2)以除杂后的铝土矿尾矿为原料合成刚玉-莫来石复相材料时,最佳合成温度为1 500℃。

In order to explore a new path to utilize bauxite tailings,the bauxite tailings were firstly desiliconized by the low calcium sintering method to remove impurities, and then the corundum-mullite refractories were synthesized. The effects of the calcia ratio of n（CaO）/[ n（SiO2） ＋ n（TiO2）] in the mixture of bauxite tailings-sodium hydroxide-calcium carbonate, alkali ratio of [ n（Na2O） ＋ n（K2O） ]/[ n（Al2O3 ） ＋ n（SiO2） ＋ n（Fe2O3）] ] and calcination temperature （950- 1 250 ℃） on the impurities＇ removal were investigated ,and the effect of the firing temperature （1 300 -1 500 ℃） on the phase composition of the synthesized corundum-mullite refractories from pre-treated bauxite tailings was followed detected. The results indicate that. （ 1 ） the optimal conditions for removing impurities from bauxite tailings are 1 150 ℃ for 2 h, 1.0 of the alkali ratio and 1.0 of calcia ratio; correspondingly,the extraction efficiency of Al2O3 is 88.40%, and the removal efficiency of SiO2, Fe203 and TiO2 are 59.02% ,98.65% and 98.57%, respectively. （2） For the corundum-mullite refractories prepared from pre-treated bauxite tailings,the optimal firing temperature is 1 500 ℃.