利用磷尾矿烧制轻质陶粒及其性能研究

On lightweight ceramsite smelting from phosphorus tailings and its properties to be achieved

针对磷尾矿利用率低而造成的环境污染及资源浪费等问题,以磷尾矿为主要原料,粉煤灰为校正原料,硬脂酸为造孔剂,并以氧化钙、氢氧化钾和氢氧化钠为辅助原料烧制轻质陶粒,研究了硅铝比、难熔组分与助熔组分含量比值(以下简称n值)、硬脂酸用量以及烧结温度对轻质陶粒性能及物相组成的影响。结果表明,烧制轻质陶粒的硅铝比应为2.2~4.0,堆积密度随n增大呈下降趋势,烧结温度对吸水率和颗粒强度影响显著,随烧结温度升高,颗粒强度越大,吸水率则逐渐降低。当硅铝比为2.52、n=6、硬脂酸添加量为20%、烧结温度为1160℃、保温时间25 min时,所制得的轻质陶粒各项性能指标满足GB/T 17431.1—2010轻集料及其试验方法中密度等级为700的质量要求,表明该技术具有实际生产应用价值,可为磷尾矿资源综合化利用提供新途径。

The given paper is aimed at investigating the influence of the silica-alumina ratio,the ratio of the refractory component to the molten component(n),in addition to trace of the effect of the stearic acid dosage and the sintering temperature on the property and the phase composition of the light ceramsite.As a matter of fact,the low utilization rate of the phosphorus tailings may bring about environmental pollution and resource waste.This is because that the phosphorus tailings are the main raw material whereas the pulverized coal is a kind of raw material regulation.And,what is more,the waste can also be made to aggravate by using the stearic acid as the pore formulating agent and calcium oxide,with the potassium hydroxide and sodium hydroxide being auxiliary materials.The results of our research show that adding proper amount of fly ash can help to reduce the Si/Al ratio of the raw material so as to improve the porosity morphology at high temperature sintering effectively and refine the porosity structure of ceramsite.In addition,adding calcium oxide,potassium hydroxide and sodium hydroxide can also make the n in the proper range ensure the ceramsite firing appropriateness in the liquid phase and promote the solid phase to proceed smoothly.Say,when the ratio of Si to Al become 2.2-4.0,it would make the accumulation density decrease with the increase of the n value.Moreover,since the sintering temperature has a significant effect on the water absorption,the particle strength tends to increase with the gradual decrease of water absorption and increase of sintering temperature.And,when the ratio of silicon to aluminum remains at 2.52 with the n being at 6,adding stearic acid in a ratio of 20%,at temperature of 1160℃for a period of 25 min,the performance indexes of the lightweight ceramsite can be expected to meet the quality demands of GB/T 17431.1—2010 Lightweight aggregate and the density level of 700 in the test method.This may signify that the technology under way has its own practical value of production and application.Hence,the research result we have gained is in a position to provide a novel approach to the comprehensive utilization of the phosphorus tailings.