Iron tailing-based complex mineral admixture and preparation process thereof

Abstract

The invention relates to an iron tailing-based complex mineral admixture and a preparation process thereof. The preparation process comprises the following steps of: respectively drying iron tailing sand, industrial waste slag and limestone till water content is not more than 1% for later use; adding gypsum to match with iron tailings, the industrial waste slag and the limestone after drying, then sending into a ball grinding machine to perform powder grinding, and adding grinding aids during the powder grinding process; and uniformly mixing the obtained iron tailing powder, industrial waste slag powder and limestone powder to obtain the iron tailing-based complex mineral admixture. The iron tailing-based complex mineral admixture disclosed by the invention has the beneficial effects that 1) the iron tailings are matched with other industrial waste slag, the admixture for concrete is prepared by simple mechanical fine grinding, and the performance is better; 2) the performance is good, and the iron tailing-based complex mineral admixture can be used for preparing the concrete with the strength grade of C50-C80; 3) a variety of industrial wastes are scientifically and effectively compounded, the activity and particle size synergy of each component against cement and the concrete can be fully exerted to enable the advantages of all the components to complement each other, and the over-superimposed effect is further realized; and 4) the production process is simple and conductive to industrial production, popularization and application.

Description

technical field [0001] The invention belongs to the technical field of building materials, and particularly relates to resource utilization of iron tailings, in particular to an iron tailings-based composite mineral admixture for cement and concrete and a preparation process thereof. Background technique [0002] Tailings have become the solid waste with the largest output and the lowest comprehensive utilization rate in my country. According to incomplete statistics, the cumulative stockpiles of tailings produced by the development of mineral resources in my country have exceeded 10 billion tons, and are currently growing at a rate of about 1.2 billion tons / a, and the annual comprehensive utilization is less than 200 million tons. Such a low comprehensive utilization rate is not only a waste of resources, but also poses a huge threat to the environment. The utilization of tailings at home and abroad mainly includes the production of cement, construction sand, aerated concr...

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Problems solved by technology

[0003] Invention patent CN101121579A "A Method of Using Iron Tailings to Produce Concrete Active Admixtures" discloses a method for producing concrete active admixtures by using magnetite-quartzite iron tailings instead of part of slag fine powder. The active admixture produced by this technology has high activity, but the iron tailings in it need to be ground and pretreated before being turned into an active admixture through thermal alteration reaction. The alteration reaction process is relatively complicated and difficult for industrial production. The altering agent is mainly composed of 14 inorganic salts such as sulfates, nitrates, carbonates, chlorides and fluorides. The existence of these substances will have an adverse effect on the workability and durability of concrete.

[0004] Invention patent CN101182141A "A Method for Using Iron Tailings to Prepare High-Strength Structural Materials" and Invention Patent CN102658596A "A Method for Using Fly Ash and Iron Tailings to Prepare High-Strength Concrete Materials" both disclose a method of using iron tailings as the main The methods of preparing cementitious materials from raw materials and preparing high-strength structural materials of fine aggregate concrete with iron tailings as fine aggregates. Although the above two technologies can consume iron tailings in large quantities and save natural sand and gravel, the iron tailings-based iron The preparation of tailings cementitious material needs to go through three-stage gradient grinding, the preparation process is complicated, and industrial production is difficult to realize

However, in recent years, with the increasingly prominent characteristics of poor, miscellaneous and fine metal mine resources in my country, mineral processing enterprises have generally increased the grinding fineness, and most of them have The tailings have been re-grinded, resulting in the median particle size of the re-selected tailings being reduced from 200 μm to about 40 μm. These too fine tailings are no longer suitable for construction sand, so iron tailings are replaced in this technology Viability of some natural sands will be limited

In addition, the iron tailings involved in this technology are used to prepare composite admixtures for concrete, the maximum amount of which is 45% in the composite admixtures, and the utilization rate of iron tailings as admixtures is not high

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