Reclaimed surface plastering gypsum for building and preparation method thereof

Abstract

The invention discloses reclaimed surface plastering gypsum for a building and a preparation method thereof. The plastering gypsum comprises the following components in parts by mass: 250-300 parts ofsalt gypsum, 10-20 parts of a solubilizing agent and 10-30 parts of a reinforcing admixture, and the solubilizing agent comprises DTPMP.Na7, potassium formate and zeolite powder according to a mass ratio of 1:2:1, and the reinforcing admixture comprises a retarder, a water-retaining agent, latex powder, desulfurized gypsum, zinc powder and hydrated iron oxide gel. The invention further disclosesa preparation method of the plastering gypsum, so that salt gypsum is recycled, and the plastering gypsum is high in operability and good in waterproof and moisture-proof performance.

Description

technical field [0001] The invention relates to the technical field of building materials, in particular to a plastering gypsum for surface layer of recycled buildings and a preparation method thereof. Background technique [0002] Salt gypsum is the waste residue produced by the salt industry. Its main component is calcium sulfate dihydrate containing a large amount of sodium chloride. Plastering gypsum is a high-efficiency and energy-saving building interior wall and ceiling plastering and leveling material with gypsum as the main cementitious material. Compared with cement plastering materials, gypsum plastering materials have a lower bulk density, only half of traditional cement plastering materials, which can effectively reduce building loads. Plastering gypsum is divided into bottom plastering gypsum, surface plastering gypsum, and lightweight bottom plastering Lime gypsum and plastering gypsum for insulation layer, using salt gypsum to prepare plastering gypsum for th...

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Problems solved by technology

[0003] However, due to the high evaporation rate and high calcium sulfate nucleation rate of salt gypsum in the salt making process, the precipitated gypsum particle size is small, the median particle size is about 4-6 microns, and the specific surface area is large. Therefore, the salt gypsum is washed to separate sodium chloride. It becomes very difficult. At the same time, due to the high content of chloride ions, it can combine with calcium ions in gypsum to form calcium chloride. Calcium chloride is very easy to absorb water and get damp. Plastering gypsum will appear damp and yellow, making it difficult to reuse salt gypsum

[0004] Salt gypsum is the same as other recycled gypsum. The strength of recycled gypsum is about 50% lower than that of primary gypsum, while the water absorption rate is about 40% higher. Moreover, the 2h strength of recycled gypsum is lower than 1.73MPa, and the compressive strength is lower than 2.9MPa, which do not meet the standards. Therefore, it cannot be reused as building gypsum, which is why currently recycled gypsum, including salt gypsum, is mainly used as a soil improver or cement additive, but is hardly used in building products

[0005] In the prior art, Patent No. CN201910268966.6 discloses a machine-sprayed surface layer plastering gypsum with purification function and its preparation method. Phosphogypsum is used as a raw material, and a purifying agent is used to make harmful elements in the phosphogypsum impermeable and degradable There are toxic gases in the air, which replace the traditional natural gypsum and desulfurized gypsum to realize the reuse of solid waste, but the chemical force generated by the curing agent can close the diffusion path of impurity ions, and enhance the cohesion of phosphogypsum particles. In the process of water coagulation and hardening, the glue is solidified, which makes it less operable when applied. At the same time, as the surface layer of plastering plaster, its waterproof and moisture-proof performance needs to be improved.

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