化学-高温-机械复合活化金尾矿及机理分析

Chemical-Thermal-Mechanical Composite Activation of Gold Tailings and Its Mechanism Analysis

尾矿制备辅助胶凝材料是实现尾矿产业化资源利用和减少建筑业碳排放的重要途径.主要探究了不同活化方法下金尾矿的活性机理和水化特性.采用高温活化、机械活化和化学-高温-机械复合活化等方法激发金尾矿的活性,探究不同活化方式对金尾矿活性的影响.测定标准稠度用水量和凝结时间,分析不同金尾矿掺量对复合胶凝材料物理性能的影响.通过XRD分析、SEM分析和火山灰试验研究了金尾矿的活化机理和水化特性.结果表明:化学-高温-机械复合活化效果>高温-机械复合活化>机械活化>高温活化.在化学-高温-机械复合活化下,较原金尾矿28 d抗压强度比(58.25%),治化后的金尾矿强度提高到74.98%.高温活化和机械活化会使得金尾矿的主要矿物相结晶度降低,但火山灰活性较低.CaO的存在有助于进一步降低结晶度,并在水化反应过程中,其提供的碱性环境,会产生活性SiO_(2)和Al_(2)O_(3),加速Ca(OH)_(2)与活性SiO_(2)和Al_(2)O_(3)反应,C—S—H凝胶和铝酸盐水合物含量增多,结构更加致密,抗压强度得到提升.

The preparation of composite cementitious materials from tailings is an important way to realize the utilization of tailings industrialization resources and reduce carbon emissions in the construction industry.This paper focuses on the activation mechanism and hydration characteristics of gold ore tailings under different activation methods.High-temperature activation,mechanical activation,and chemical-high temperature-mechanical composite activation were used to enhance gold tailings activity,and the influence of activation methods on gold tailings activity was analyzed.The water consumption and standard consistency setting time were measured to analyze the effect of different gold tailings content on the physical properties of composite cementing materials.The activation mechanism and hydration characteristics of gold tailings were revealed by XRD analysis,SEM analysis,and pozzolans property test.The results show that the activation effect is as follows:chemical-high temperaturemechanical composite activation>high temperature-mechanical composite activation>mechanical activation>thermal activation.Under the chemical-high temperature-mechanical composite activation,the compressive strength ratio of the gold tailings mortar test block in 28 days was 74.98% and 58.25% higher than that of the original gold tailings.The crystallinity of the main mineral phases of gold tailings tends to decrease after high-temperature activation or mechanical activation,but the activity of pozzolanic ash is low.The presence of CaO is helpful for further reducing crystallinity,and the alkaline environment provided in the hydration reaction process can obtain active SiO_(2) and Al_(2)O_(3),and accelerate the reaction of Ca(OH)_(2) with active SiO_(2) and Al_(2)O_(3).The content of C—S—H gel and aluminate hydrate increases,the structure is denser,and the compressive strength is improved.