A semi-dry method for preparing high-strength α-hemihydrate gypsum

A semi-hydrated gypsum and semi-dry technology, which is applied in the field of building materials, can solve the problems of high equipment investment, large component fluctuations, and high production costs, and achieve the effects of reducing environmental pollution, reducing heat loss, and small equipment investment

Active Publication Date: 2018-02-09
湖南省小尹无忌环境能源科技开发有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Compared with autoclave method, hydrothermal method, salt solution co-crystallization method and compromise method, the production energy consumption of dry stuffing method is the lowest. However, it needs to use jacketed autoclave equipment, which has low efficiency and equipment investment. On the high side, the production cost is on the high side. Second, the product mineral is a mixture of β-hemihydrate gypsum and α-hemihydrate gypsum, and the composition fluctuates greatly, and the strength is low (generally 10-20MPa)

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] The gypsum raw material is natural dihydrate gypsum, the particle surface modifier in the modifier is sodium metaaluminate, and the crystal modifier for adjusting the dissolution and crystallization habit in the modifier is commercially available powdered melamine water reducing agent. agent, polyglycerin and sodium glutarate. Prepare α-hemihydrate gypsum by semi-dry method as follows:

[0036] (1) Material preparation: crush 2000g of dihydrate gypsum to a particle size below 2mm; mix 18g of particle surface modifier sodium metaaluminate (0.9% of the mass of dihydrate gypsum), 8g of crystal form modifier melamine superplasticizer 1. 1 g of polymerized glycerin and 1 g of sodium glutarate (0.5% of the mass of dihydrate gypsum in total) were dissolved in 150 g of water to make 178 g of modifier aqueous solution with a water content of 84.3%;

[0037] (2) Preparation of wet material: Mix 2000g of dihydrate gypsum granular material with a particle size below 2mm obtained i...

Embodiment 2

[0043] The gypsum raw material is natural dihydrate gypsum, the particle surface modifier in the modifier is polymerized silica sol, and the crystal form modifier for adjusting the dissolution and crystallization habit in the modifier is commercially available powdered sodium naphthalenesulfonate water reducing agent. agent, polyethylene glycol ether, polymerized glycerin. Prepare α-hemihydrate gypsum by semi-dry method as follows:

[0044] (1) Material preparation: crush and grind 2000g of dihydrate gypsum into 80 micron sieve with 18% powder; add 18g of particle surface modifier polymerized silica sol (0.9% of the mass of dihydrate gypsum), crystal form modification 10g of sodium naphthalenesulfonate superplasticizer, 1g of polyethylene glycol ether, and 1g of polyglycerol (0.6% of the mass of dihydrate gypsum in total) were dissolved in 200g of water to prepare 230g of modifier aqueous solution with a water content of 86.9%;

[0045] (2) Preparation of wet material: mix 20...

Embodiment 3

[0051] The gypsum raw material is phosphogypsum, the particle surface modifier in the modifier is polymerized silica sol, and the crystal form modifier for adjusting the dissolution and crystallization habit in the modifier is commercially available liquid sulfamate water reducer, poly Glycol ethers, Polyglycerin. Prepare α-hemihydrate gypsum by semi-dry method as follows:

[0052] (1) Preparation: add 2000g of granular phosphogypsum to lime (40g) equivalent to 2% of the weight of phosphogypsum, mix and age for 3 days to neutralize the soluble phosphate and fluorophosphate in phosphogypsum, and then crush it to the particle size 2mm or less; 16g of particle surface modifier polymerized silica sol (0.8% of the mass of phosphogypsum), 12g of crystal form modifier sulfamate water reducer, 1g of polymerized glycerin, and 1g of polyethylene glycol ether (total 0.7% of the mass of phosphogypsum) was dissolved in 200g of water to make 230g of modifier aqueous solution with a moistur...

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Abstract

A method for preparing high-strength α-hemihydrate gypsum by a semi-dry method, comprising the following steps: (1) material preparation: crushing dihydrate gypsum to a particle size below 5mm, or grinding it into a powder with an 80 micron sieve <50% ;Dissolve the modifier in water to make a modifier aqueous solution with a moisture content of <95%; (2) Prepare wet materials; (3) Semi-dry steaming to prepare α-hemihydrate gypsum; (4) Dry (5) Manufacture: Grinding the dried α-hemihydrate gypsum material obtained in step (4) into a powder with a sieve residue <12% of 80 microns to obtain high-strength gypsum powder. The invention has the advantages of simple process, small equipment investment, simple control of process parameters, preventing the occurrence of β-hemihydrate gypsum, easy and stable product quality, and can minimize the production energy consumption of high-strength gypsum and effectively reduce production costs.

Description

technical field [0001] The invention relates to the field of building materials, in particular to a method for preparing high-strength α-hemihydrate gypsum by a semi-dry humid heat steaming method (semi-dry method for short). Background technique [0002] At present, gypsum (calcium sulfate) exists in the following states: dihydrate gypsum, hemihydrate gypsum, type III anhydrous gypsum, type II anhydrous gypsum, and type I anhydrous gypsum (also called α-type anhydrous gypsum). Both dihydrate gypsum and hemihydrate gypsum are in a metastable state, and can be transformed into each other under certain conditions. After the water molecules between the two ion layers of dihydrate gypsum escape 3 / 4, that is, 1.5 water molecules, Ca 2+ with SO 4 2- Stagger each other to form hemihydrate gypsum. The hemihydrate gypsum formed by dihydrate gypsum under different heating and dehydration conditions has no essential difference in the microscopic atomic arrangement; but in its micros...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B11/02C04B11/032
Inventor 尹无忌尹小林
Owner 湖南省小尹无忌环境能源科技开发有限公司
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