Copper tailings-based active mineral admixture capable of inhibiting concrete alkali silicic acid reaction and its preparation method and application

Abstract

The invention provides a copper tailings-based active mineral admixture capable of inhibiting concrete alkali silicic acid reaction, a preparation method and application thereof, and relates to the technical field of comprehensive utilization of solid waste reduction. The admixture capable of inhibiting the reaction of alkali-silicic acid in concrete is mainly prepared by sequentially magnetizing copper tailings, removing high-alkali active minerals and unfavorable components, and then activating. The copper tailings-based active mineral admixture prepared by the above specific process has the advantages of high pozzolanic activity and fine particle size. After testing, the activity index of the admixture is >70%, and the fineness of the 45um square hole sieve is <2%. The application of the above-mentioned copper tailings-based active mineral admixture in concrete can give full play to its filling effect, morphological effect, interface effect and dilution effect, and improve the performance of concrete, thereby effectively reducing the risk of alkali silicic acid reaction in concrete. The comprehensive utilization of bulk reduction of tailings provides a feasible technical path.

Description

technical field [0001] The invention relates to the technical field of comprehensive utilization of solid waste reduction, in particular to a copper tailings-based active mineral admixture capable of inhibiting concrete alkali silicic acid reaction and its preparation method and application. Background technique [0002] The overall grade of copper ore in my country is low, so the output of copper tailings is very large. In 2019, the output of copper tailings in my country is about 325 million tons, which is second only to iron tailings and is the second largest annual output of tailings in my country. Copper tailings It is imminent to reduce, absorb, process and utilize mines. Under the strict environmental protection policy, many mines in China have invested in the exploration of resource utilization of tailings. The main foothold and feasible solution is the utilization of building materials, such as using tailings as bricks, refractory materials, glass, ceramsite, ceramic...

AI Technical Summary

Problems solved by technology

Under the strict environmental protection policy, many mines in China have invested in the exploration of resource utilization of tailings. The main foothold and feasible solution is the utilization of building materials, such as using tailings as bricks, refractory materials, glass, ceramsite, ceramics and other raw materials, but these resource utilization methods still cannot solve the problem of large tailings volume; and tailings reduction utilization methods such as underground cementing and filling of tailings dams, tailings dams and land reclamation have low added value and even require relatively large resources. Therefore, from the perspective of scale reduction and consumption of tailings, the use of tailings in the cement and concrete industry is currently the most important utilization method, and this utilization direction has become a hot topic in the research of tailings reduction utilization

[0003] A large amount of stockpiling of tailings has caused a serious waste of resources, restricted the normal production of enterprises, formed serious environmental pollution and huge safety hazards. Among them, copper tailings are currently unavailable due to their fine particle size and high content of unfavorable components. Reasonable ways to reduce and comprehensively utilize it; at the same time, the high energy consumption and high pollution characteristics of the cement concrete industry urgently need to find new and cheap alternative raw materials, and study the use of copper tailings with potential hydraulic activity or volcanic ash characteristics. The dosage of alternative concrete active mineral admixtures is an important topic with considerable application value and social and economic significance

The silicate minerals and potential pozzolanic activity in copper tailings make it possible to replace part of the concrete active mineral admixtures to prepare high-performance concrete. Pay less attention to whether the addition of tailings will cause alkali silicic acid reaction (ASR) in concrete and the suppression methods

[0004] Alkali silicic acid reaction is the most important factor that causes damage to concrete structure and affects the durability of concrete. The reaction cycle is long and the process is complicated. It can be described as a potential "cancer" of concrete. The concrete structure that has cracked by ASR is irreparable. Therefore, the possibility of ASR can only be reduced through prevention

Existing studies have shown that the addition of active mineral admixtures is an effective means to prevent the occurrence of ASR, and whether the use of copper tailings in concrete admixtures after activity control can avoid the impact of the complex and multivariate characteristics of the tailings on the occurrence of ASR. Potential risks are the constraints on whether the tailings reduction and consumption pathway can be implemented smoothly

Images