基于矿物蒸压活性及竞争反应的多元固废蒸压体系优化设计研究

This project is based on the resource utilization of the large amount of siliceous tailings in the autoclaved construction materials, dealing with the complex composition of siliceous tailings and the high fluctuation of the reaction activity of silicon minerals, regarding quartz, mica and feldspar which were the most common silicon-containing minerals in siliceous tailings as research object. From the angle of autoclaving reaction activity and competitive reaction mechanism of silicon-containing minerals under alkaline environment, through the influence of mixing ratio, particle characteristics on physical and mechanical performance, qualitative and quantitative of silicon-containing minerals and calcium hydroxide autoclaved system, this project ascertained mineral transformation process and autoclaved reactivity of autoclaved hydrothermal reaction between single-component silicon-containing minerals and calcium hydroxide, put forward a method for the evaluation of autoclave reaction activity of silicon containing minerals and calcium hydroxide based on the hydrothermal reaction of quartz and calcium hydroxide. The competition and regulation mechanism of the hydrothermal reaction of silicon-containing minerals in alkaline environment was investigated through the quantitative study of hydration products and minerals of multivariate composite silicon-containing minerals autoclaving system. Based on silicon-containing minerals autoclaved reactivity and competition mechanism, combined with the complex mineral raw material system basicity coefficient (Kalk) control theory, the optimum design method for the autoclaving system of low active and complex mineral raw materials based on mineral composition is proposed. This project provides a theoretical basis for process optimum design of autoclave products preparation from siliceous tailings.

本项目以我国排放的巨量硅质尾矿在蒸压建筑材料中的资源化利用为背景，针对硅质尾矿矿物组成复杂，含硅矿物蒸压反应活性波动大等特征，以石英、云母、长石三种硅质尾矿中最普遍的含硅矿物为研究对象。从含硅矿物在碱性环境下的蒸压反应活性与竞争反应角度，本项目通过含硅矿物与氢氧化钙蒸压体系的配合比、颗粒特性对物理力学性能、水化产物种类与形成量的影响研究，探明单一含硅矿物与氢氧化钙的蒸压水热反应矿物转变过程及其蒸压反应活性，提出以石英与氢氧化钙蒸压水热反应为基准的含硅矿物蒸压反应活性评价方法；通过对多元组合含硅矿物蒸压体系水化产物与矿物的定量研究，探明碱性环境下含硅矿物的蒸压水热反应竞争机制与调控方法；基于含硅矿物的蒸压反应活性与竞争机制，结合复杂矿物原料体系碱度系数（Kalk）控制理论，提出基于矿物组成的低活性复杂矿物原料蒸压体系优化设计方法。本项目为硅质尾矿制备蒸压制品的工艺优化设计提供理论依据。

本项目针对硅质尾矿矿物组成复杂，含硅矿物蒸压反应活性波动大造成在蒸压建筑材料中难以大规模应用的问题。以石英、云母、长石三种硅质尾矿中最普遍的含硅矿物为研究对象，从含硅矿物在碱性环境下的蒸压反应活性与竞争反应角度开展研究。本项目开展了典型含硅矿物的蒸压水热反应过程研究，并对云母类和长石类含硅矿物的蒸压水热反应活性进行了评价。研究结果表明，在硅质材料中的活性排序大致为石英＞钾长石＞钠长石＞金云母＞白云母，长石类（钾长石、钠长石）的蒸压水热反应活性显著高于云母类（白云母、金云母）。同时开展了碱性环境下的多元含硅矿物蒸压水热反应竞争机制与调控方法研究。研究结果表明，使用石英-云母-氢氧化钙进行蒸压水热反应时，氧化铝和硫酸钙对含硅矿物溶解和反应率没有显著的提升效果，使用石英-长石-氢氧化钙进行蒸压水热反应时，掺加氧化铝和硫酸钙对于钾长石和钠长石参与蒸压水热反应有促进作用，而这两种物质的掺入，均对提升托贝莫来石的生成有促进作用。基于上述实验研究，结合复杂矿物原料体系碱度系数（Kalk）控制理论，在低活性含硅尾矿制备蒸压建筑材料时，在利用长石类含硅矿物为主的尾矿时，可以通过调配硫酸钙和氧化铝的掺量，适当延长蒸压水热养护时间，促进长石类参与反应；在利用云母类含硅矿物为主的尾矿时，需尽可能的提高粉体细度，提升在蒸压条件下的溶解度，从而提高其反应率。