利用金矿尾砂制备矿物聚合材料的实验研究

EXPERIMENTAL STUDY OF THE GEOPOLYMERS SYNTHESIZED WITH GOLD-TAILINGS

利用北京平谷金矿尾砂、变高岭石、NaOH、KOH和水玻璃制备了矿物聚合材料 ,正交实验结果表明 35℃时的优化条件为尾砂含量 80 %～ 82 5 %、固 /液比 4 3～ 4 7、水 /碱比为4～ 5 (均为质量比 ) ,升高温度、延长固化时间及室温放置时间均会使矿物聚合材料的抗压强度显著提高。将金矿尾砂制备成矿物聚合材料 ,可使部分CN-转化成无害的CO2 -3 和H2 ,其他则以夹持 (物理 )方式固定下来 ;当存在Fe2 +或Fe3+离子时 ,CN-以氰化铁的化学方式固定下来。该矿物聚合材料在 1mol/L的HCl溶液中浸泡 30d ,质量损失 5 6 % ,结构完好 ,表现出良好的抗酸性。在 6 0℃下固化 2 4h ,室温放置 6d后抗压强度为 2 2MPa ;在 6 0℃下固化72h ,抗压强度为 36 6MPa。该研究为金矿尾砂的利用提供了一条新途径。

The geopolymers were synthesized using gold-tailings, metakaolin, water glass, sodium and potassium hydrate. With the method of orthogonal experiments, the optimized result is gold-tailings of 80%-82.5%, powder to alkaline silicate solution mass ratios of 4.3-4.7 and water to alkaline mass ratios of 4-5. Based on these results, it is found that the compressive strength is largely enhanced by raising temperature and elongating hardening time as well as staying time in the air. The serious poisonous CN- in the gold-tailings can be trapped physically in the geopolymers and fixed chemically in the geopolymers when CN- meets with Fe 2+ or Fe 3+. The mass loss of the geopolymers soaked in 1 mol/L HCl for 30 days averages 5.6%, showing a good acid-resistance, concerning its 9% hematite and 6% calcite in gold-tailings. At 60℃, with hardening time of 24 hours and 72 hours, the compressive strength of the geopolymers reaches 22 MPa after another 6 days in ambient condition and 36.6 MPa, respectively. This result provides the possibilities for geopolymers utilized as construction blocks in industry.