What are the uses for waste gypsum?

How to use gypsum? Phosphogypsum accounts for a high proportion of waste gypsum, and waste gypsum is also one of the main sources of pollution. So how can waste gypsum be used to achieve near-zero pollution, achieve environmental greening, and achieve economic benefits?

How to use waste gypsum? First you need to know what its ingredients are

Waste gypsum refers to the industrial waste residue with calcium sulfate dihydrate (Ca-s04.19.H70) as the main component in the chemical production process or waste treatment process. It is commonly known as chemical gypsum. The main components include phosphogypsum, fluorogypsum, titanium gypsum, lemon gypsum, etc. There are several categories such as acid gypsum, salt gypsum, mirabilite gypsum and flue gas desulfurization gypsum. The particle size of waste gypsum is generally between 5 and 150 microns, in powder form, and the calcium sulfate content is generally above 80%. Waste gypsum mainly utilizes phosphorus, sulfur, calcium, nitrate and other trace elements.

Taking phosphogypsum as an example, incomplete statistics show that for every ton of phosphoric acid produced in 58 countries around the world, approximately 5 tons of phosphogypsum are discharged. In many countries, emissions of phosphogypsum exceed the mining of natural gypsum. For this reason, how to utilize waste gypsum is a major issue involving the sustainable development of human society. How to use waste gypsum can turn waste into treasure and improve the comprehensive benefits of waste gypsum processing enterprises, which is of great significance to building a circular economy and resource-saving society in my country.

The harm of waste gypsum is huge, how to use waste gypsum has become an important reason

Improper disposal of waste gypsum can even harm people and animals, or even pollute soil and water sources, and occupy land. How to utilize waste gypsum is an important issue that needs to be considered in industrial solid waste treatment.

How to use waste gypsum? The most common method is to grind waste gypsum into powder less than 40μm (0.04mm) and use it as cement mineralizer, which can promote the decomposition of CaC03 in raw materials, make the liquid phase appear in advance during the clinker formation process, and reduce the firing temperature and liquid viscosity. Promote liquid phase crystallization, facilitate solid phase and liquid phase reactions, and generate transition phases that are beneficial to the formation of clinker minerals.

Secondly, how to use waste gypsum is mainly to process industrial waste gypsum into powder below 300 mesh, which can be used as the basic raw material for building gypsum powder and model gypsum powder to produce different products.

Grinding waste gypsum into powder less than 325 mesh to make co-produced cement has become an important technology in areas where sulfur resources are scarce.