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Starch sulfate efficient water-reducing retarder and preparation method thereof

A technology of starch sulfate and high-efficiency water reducer, which is applied in the field of concrete admixtures, can solve problems such as difficult recycling, increased costs, and performance degradation, and achieves low raw material costs and equipment requirements, improved reaction efficiency, and good retarding effect Effect

Active Publication Date: 2019-02-05
殷鸽
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the third-generation water reducer has the following disadvantages in the process of use: (1) The prepared concrete is easy to separate and segregate, and bleeding is serious
(2) The stability of product performance is poor, especially for sand and gravel aggregates with high mud content or stone powder content, its performance will drop significantly when used
In this method, 95% ethanol and hydrochloric acid are used to heat dextrin before starch sulfonation, and impurities such as chloride ions introduced in the dextrin preparation process need to be purified and removed, which not only increases the complexity of the process, but also improves the quality of the product. the cost of
In addition, the dispersant dimethylformamide and the sulfonating agent sulfamic acid used in the sulfonation process of dextrin are expensive, and the recovery of the former and the unreacted latter is difficult, so it is difficult to have industrialization prospects
[0004] In a word, although the existing starch-based water reducer has patents and literature reports, no commercial products have come out.

Method used

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  • Starch sulfate efficient water-reducing retarder and preparation method thereof
  • Starch sulfate efficient water-reducing retarder and preparation method thereof
  • Starch sulfate efficient water-reducing retarder and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Mix concentrated sulfuric acid and formamide uniformly at a molar ratio of 1:0.05, cool for later use; then take 0.2 moles of cornstarch with a purity of 86% and put it into a booster electric stirring reactor, and add dichloroethylene that is 1.0 times the volume of cornstarch alkane, stir and mix for 30 minutes; then add the mixture of concentrated sulfuric acid and formamide according to the molar ratio of starch anhydroglucose unit and concentrated sulfuric acid as 1:0.5; control the reaction temperature not to exceed 55°C until the system no longer exotherms and cool to room temperature , Separation and recovery of dichloroethane. The resulting reaction mixture was neutralized to pH 7 with aqueous sodium hydroxide solution, and adjusted with water to form a starch sulfate retarded high-efficiency superplasticizer solution with a solid content of 30%.

[0029] The concentrated sulfuric acid used in this embodiment and the following embodiments is sulfuric acid with ...

Embodiment 2

[0031] Mix concentrated sulfuric acid and formamide uniformly at a molar ratio of 1:0.2, cool for later use; then take 0.5 moles of cornstarch with a purity of 90% and put it into a booster electric stirring reactor, and add chloroform with 1.5 times the volume of cornstarch , stirred and mixed for 30 minutes; then add the mixture of concentrated sulfuric acid and formamide according to the molar ratio of starch anhydroglucose unit and concentrated sulfuric acid as 1:1; control the reaction temperature not to exceed 40°C until the system no longer exothermic, cool to room temperature, Separation and recovery of chloroform. The resulting reaction mixture was neutralized to pH 7.5 with aqueous sodium bicarbonate solution, and adjusted with water to form a starch sulfate retarded high-efficiency superplasticizer solution with a solid content of 30%.

Embodiment 3

[0033] Mix the concentrated sulfuric acid and urea with a molar ratio of 1:0.38, cool it for later use; then take 0.8 moles of cornstarch with a purity of 94.5% and put it into a booster electric stirring reactor, and add dichloromethane that is 2.0 times the volume of cornstarch, Stir and mix for 30 minutes; then add the mixture of concentrated sulfuric acid and urea according to the molar ratio of starch anhydroglucose unit to concentrated sulfuric acid is 1:1.2; control the reaction temperature not to exceed 30°C until the system no longer exothermic, cool to room temperature, separate and recover dichloromethane. The resulting reaction mixture was neutralized to pH 8.0 with an aqueous calcium hydroxide solution, and adjusted with water to form a starch sulfate retarded high-efficiency superplasticizer solution with a solid content of 30%.

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Abstract

The invention discloses a starch sulfate efficient water-reducing retarder and a preparation method thereof. The starch sulfate efficient water-reducing retarder is prepared from the following synthetic raw materials including starch, concentrated sulfuric acid, a dispersant and inorganic base and is synthesized by adopting two technologies of a wet method and a dry method. The wet method comprises the following steps of uniformly mixing the concentrated sulfuric acid and the dispersant according to a molar ratio of 1 to (0.05-1), and performing cooling standby; then throwing the starch in a reactor, and adding an organic solvent with the volume being 1-2 times of the volume of the starch; then throwing a starch anhydroglucose unit and the concentrated sulfuric acid in a mixture of the concentrated sulfuric acid and the dispersant according to a molar ratio of 1 to (0.5-2.5); and after reaction, separating and recovering the organic solvent, and then performing neutralization with a basic aqueous solution until a pH value is 7-8. The dry method comprises the following steps of uniformly mixing the concentrated sulfuric acid and the dispersant in the stirrer according to a molar ratio of 1 to (0.05-1), and performing cooling standby; then throwing the starch anhydroglucose unit and the concentrated sulfuric acid in the starch according to a molar ratio of 1 to (0.5-2.5); and after reaction, performing neutralization with a basic aqueous solution until a pH value is 7-8. The preparation method has the advantages of convenience in operation, no three-waste pollution, low raw material cost, low equipment requirement and the like.

Description

technical field [0001] The invention relates to the technical field of concrete admixtures, in particular to a starch sulfate retarding high-efficiency water reducer. Background technique [0002] Water reducer is a concrete admixture. It can improve the working performance of concrete mixture under the condition of constant water-cement ratio; under the condition of constant workability of concrete and cement dosage, it can reduce mixing water consumption and improve concrete strength; under the condition of constant concrete strength Under certain conditions, reduce the cement consumption per unit. The development of water reducing agent mainly goes through three stages. The first generation of ordinary water reducing agent is represented by sodium lignosulfonate, which has a low water reducing rate and poor concrete fluidity, which cannot meet the pouring of high-strength and high-grade concrete. The second generation of high-efficiency water reducers are represented b...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08B31/06C04B24/38C04B103/30
CPCC04B24/38C04B2103/30C08B31/063
Inventor 殷鸽
Owner 殷鸽