Inorganic thermal insulation mortar is mainly composed of inorganic lightweight aggregates, cementitious materials, additives and other admixtures with internal porous and thermal insulation properties. Material. In recent years, combined with the problem of massive accumulation of industrial solid waste, it has become a research hotspot for experts and scholars to effectively apply it to inorganic thermal insulation mortar.

Industrial solid waste (referred to as industrial solid waste) refers to fuel waste, smelting and chemical process waste, mining waste rock or beneficiation tailings discharged during industrial production and processing that no longer have use value or have been extracted from useful components. the remaining waste. In 2012, my country’s Ministry of Industry and Information Technology designated tailings, coal gangue, fly ash, smelting slag, and by-product gypsum as key industrial solid waste treatment targets.

1. Using industrial solid waste to produce light aggregates
Lightweight aggregates mainly play the role of skeleton and thermal insulation in inorganic thermal insulation mortar. In addition to the existing light aggregates such as vitrified microbeads and expanded perlite on the market, industrial solid waste can also meet the performance requirements of low density and high strength. Some experts use silt pottery sand and waste aerated concrete composite vitrified microbeads as insulation mortar aggregates to prepare two kinds of self-insulation wall supporting mortar. Some experts used fly ash, calcium carbide slag and desulfurized gypsum as the main raw materials, and adopted a low-temperature firing process to successfully prepare a new type of inorganic cementitious material with a porous structure. Studying the use of waste resources to produce lightweight aggregates for thermal insulation mortar can not only effectively reduce the production cost of thermal insulation mortar, but also be one of the directions for comprehensive recovery of industrial waste ceramic sand or aerated materials, and also provide new research on inorganic thermal insulation mortar aggregates. Technical reference.
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2. Using industrial solid waste to produce cementitious materials
The cementitious material mainly plays the role of cementation in the inorganic thermal insulation mortar, and also makes the mortar have sufficient strength and construction performance. The commonly used cementitious material is cement, but in recent years, many industrial solid wastes (slag, fly ash, desulfurized gypsum, coal gangue) have been developed as auxiliary cementitious materials.
(1) fly ash
Fly ash is one of the largest industrial waste residues in my country, and it is the main solid waste discharged from coal-fired power plants. Fly ash is light in bulk density and has certain hydraulic activity. Some experts use industrial waste fly ash as a cementitious material to replace part of the cement, and use vitrified microbeads as inorganic lightweight aggregates to prepare dry-mixed inorganic thermal insulation mortar. The research shows that with the increase of fly ash content, the compressive strength of mortar first increases and then decreases. When the fly ash content is 20%, a better thermal insulation mortar can be prepared. .
(2) Mineral powder
Adding mineral powder to the inorganic thermal insulation mortar can improve the physical and mechanical properties of the mortar, increase the strength and service life of the concrete, and at the same time improve the impermeability and water resistance.
(3) Gypsum
After gypsum is mixed with an appropriate amount of water, it can form a slurry with good plasticity. With the reaction of gypsum and water, the plasticity of the slurry disappears and coagulation occurs quickly, and the strength is further generated and developed after hardening.
Use industrial solid waste to produce admixtures and admixtures Add admixtures to inorganic thermal insulation mortar to improve the performance of mortar, and industrial solid waste can also play a similar role. The purpose of adding admixtures to thermal insulation mortar is to reduce the cost of raw materials as much as possible without affecting the performance of mortar products.

3. Use of tailings sand to produce aggregates
As one of the main industrial solid wastes, tailings sand occupies a lot of land resources and increases the cost of corporate governance. The comprehensive utilization of tailings sand has become a topic of concern to experts and scholars. Generally speaking, the addition of sand can improve the workability, physical and mechanical properties and dry shrinkage resistance of the mortar, but the high density and high thermal conductivity of sand can easily lead to an increase in the dry density of the mortar and a decrease in the gas content, which is not suitable for thermal insulation mortar. The thermal performance is unfavorable. Therefore, although tailings sand can be mixed into ordinary dry-mixed mortar as aggregates, on the basis of ensuring the thermal performance of mortar, the mixing amount and particle size distribution of sand must be strictly controlled.

4. The development trend of industrial solid waste in the application of inorganic thermal insulation mortar
The application of industrial solid waste in inorganic thermal insulation mortar can improve the performance of thermal insulation mortar and increase economic benefits on the one hand; From the current research and application situation, its development trend is as follows:
First, when industrial solid waste is used as a raw material to prepare inorganic thermal insulation mortar, the dosage should be increased as much as possible on the basis of meeting relevant standards.
Second, more types of solid waste will be applied to the production of building materials such as inorganic thermal insulation mortar, and there will be more and more researches on the mechanism of a certain type of industrial solid waste purposefully.
Third, there is currently no unified standard for thermal insulation mortar mixed with industrial solid waste. However, for several main admixture components such as fly ash, industrial gypsum, and slag powder, a unified and reasonable standard should be made based on relevant research results. nature requirements.
Fourth, when tailing sand is added as aggregate to inorganic thermal insulation mortar, different raw material formulas have strict restrictions on the particle size of tailing sand, so the application of tailing sand in inorganic thermal insulation mortar will be limited to a certain extent.