Comprehensive Utilization of Phosphogypsum in Building Materials Industry| Professional Phosphogypsum Grinding Mill

Phosphogypsum is a by-product of the phosphate and compound fertilizer industry. Its comprehensive utilization has great practical significance for environmental protection, energy saving and sustainable development of the phosphate and compound fertilizer industry. The building materials industry is an industry that consumes a lot of comprehensive utilization of phosphogypsum. Phosphogypsum can be applied to the building materials industry after calcination, grinding and other processes. HCMilling(Guilin Hongcheng) is a manufacturer of phosphogypsum grinding mills. HCM's phosphogypsum grinding mills have been widely used in the phosphogypsum comprehensive utilization industry. The following is an introduction to the comprehensive utilization of phosphogypsum in the building materials industry:

1. Use the phosphogypsum powder processed by the phosphogypsum grinding mill to prepare building cementitious materials

Using it to prepare gelling materials is mainly to dehydrate dihydrate gypsum to generate hemihydrate gypsum. Based on the atmospheric pressure salt solution method, the effects of five salt solutions of NaCl, NaNO3, MgCl2, CaCl2 and Ca(NO3)2 on the conversion rate, phase composition and morphology of α-hemihydrate gypsum prepared from phosphogypsum were studied, and the NaCl phase was obtained. Compared with other salts, it has the advantages of low dosage and fast conversion rate of phosphogypsum. The pH value of the phosphogypsum washed with water is neutral and relatively stable, and most of the hydrothermal reaction products are relatively coarse columnar crystals, which improves the performance of the α hemihydrate phosphogypsum prepared by the hydrothermal method.

β-type is made by dehydrating dihydrate gypsum in gaseous form under normal pressure. Calcining phosphogypsum to prepare β-hemihydrate gypsum optimization process, the best process conditions are obtained as calcination temperature 130 ℃, calcination time 38min. The process flow, production control, product index and economic benefits of β hemihydrate gypsum produced by FC compartmental gypsum calciner technology. In addition, the original phosphogypsum can also be mixed with lime, fly ash, cement, slag and other mineral admixtures in a certain proportion, and added with an activator to prepare a cementitious material.

2. Building material products made of phosphogypsum powder processed by a phosphogypsum grinding mill

Phosphogypsum-based building material products can be divided into brick materials and plates according to their shape. Brick materials include phosphogypsum bricks and phosphogypsum blocks. Phosphogypsum and shale are used as the main raw materials, mixed with a small amount of cinder, and the production process is the same as that of ordinary clay bricks. Gypsum blocks have the characteristics of comfort, stability, fire resistance, environmental protection and high cost performance in buildings. It will have great advantages in replacing cement blocks as interior wall materials. Gypsum boards include ordinary paper gypsum boards, decorative gypsum boards, water-resistant paper-faced gypsum boards, fire-resistant paper-faced gypsum boards, and perforated sound-absorbing gypsum boards. Features, mainly used for suspended ceilings, partition walls, interior wall veneers, ceilings, sound-absorbing panels, etc.

3. Use the phosphogypsum powder processed by the phosphogypsum grinding mill to prepare cement and cement retarder

Phosphogypsum can be used as a raw material for the production of various types of cement. The co-production of phosphogypsum acid and Portland cement can recycle sulfur and calcium elements, which not only reduces the production cost of sulfuric acid, but also solves the environmental problems caused by phosphogypsum stockpiling. However, this process needs to further solve the problems of increasing the decomposition rate of phosphogypsum at high temperature, corrosion of equipment by decomposition gas, and pipe plugging by dust. Sulphoaluminate cement is made by mixing and firing limestone, phosphogypsum, and bauxite and then adding phosphogypsum to grind it. The addition of phosphogypsum can improve the grindability of cement raw materials. In addition to the characteristics of early strength and rapid hardening, the cement also has the characteristics of anti-cracking and anti-corrosion, and is very suitable for underground, oil well, hydraulic and marine construction projects. At present, this cement is widely used in the manufacture of glass fiber reinforced concrete lightweight porous panels. By introducing calcium sulfosilicate minerals into Belite-sulfoaluminate cement, the preparation of calcium sulfosilicate-sulfoaluminate cement using phosphogypsum is studied to improve the utilization rate of phosphogypsum. Gypsum slag cement is a building material with strong impermeability and corrosion resistance, and is often used in underground and hydraulic engineering.

4. Preparation of functional building materials using phosphogypsum powder processed by a phosphogypsum grinding mill

Phosphogypsum can be used to make functional building materials. For example, phosphogypsum removes crystal water at high temperature, plays a cooling and flame retardant role, and has a fireproof function. Graphite can be added to phosphogypsum to make gypsum-based conductive materials, or non-metallic conductive materials made of nano-metal-coated gypsum whiskers, which have the functions of conducting electricity and shielding electromagnetic waves, and can be processed into electromagnetic shielding and anti-static materials for national defense construction or structures etc. Magnetized particles added to phosphogypsum can also be made into magnetic materials, which can be used in the construction of intelligent buildings or roads. Composite profiles made of phosphogypsum and polymer materials have both the corrosion resistance and weather resistance of polymer materials and the high strength and flame retardancy of inorganic materials, and are widely used in the construction industry.