Preparation method of high-performance gypsum retarder

Abstract

The preparation method comprises the following steps: S1, accurately weighing a protein raw material, dissolving the protein raw material in deionized water, carrying out high-temperature denaturation under a constant-temperature water bath condition, then adjusting to an enzymolysis temperature, adding protease for enzymolysis, then adding an alkaline substance to adjust the pH value to be neutral, heating in a boiling water bath for enzyme deactivation, and filtering to obtain a filtrate; cooling the enzymatic hydrolysate to room temperature to obtain hydrolyzed protein; s2, deionized water, acid anhydride and hydrolyzed protein are stirred in a constant-temperature water bath; then adding organic alkali or inorganic alkali to adjust the solution to be neutral, and performing powder spraying, drying and sieving to obtain intermediate powder; and S3, adding the sieved gypsum reinforcing agent into the intermediate powder, and uniformly mixing to obtain the retarder powder. The gypsum retarder can exert an excellent retarding effect at an extremely low mixing amount, has better adaptability to industrial byproduct gypsum, is wide in applicability, maintains corresponding setting time under a strong alkali condition, does not significantly increase the mixing amount, and has less influence on absolute dry strength.

Description

Technical Field

[0001] The invention relates to a method for preparing a high-performance gypsum retarder. Background Art

[0002] Building gypsum with hemihydrate gypsum as the main component sets and hardens quickly. It loses fluidity in a short time after adding water and stirring. It generally cannot meet the needs of molding and construction. Retarders must be used to control its reasonable setting time.

[0003] At present, gypsum retarders can be divided into inorganic acids, organic acids and soluble salts, alkaline phosphates, protein macromolecular compounds, amino acids and other retarders according to their composition.

[0004] Industrial by-product gypsum mainly includes phosphorus building gypsum and desulfurized building gypsum, which mainly differ in pH value, impurity type and content. Phosphorus building gypsum contains some residual phosphoric acid or soluble phosphates, and its pH value is generally less than 7, while the pH value of desulfurized building gypsum is generally neutral or weakly alkaline. During the production process, in order to improve the performance of building gypsum, strong alkaline substances such as cement and calcium oxide are often added to the product, causing some gypsum to also be alkaline. Most of the existing gypsum retarders have good applicability under neutral and weakly alkaline conditions, but have poor applicability to weakly acidic and strongly alkaline environments, and increasing the amount of retarder has a great effect on the strength. If chloride ions are introduced during the preparation of gypsum retarders, it will also have a great effect on the absolute dry strength. It is necessary to add a gypsum enhancer that has little effect on the setting time to improve the strength of the gypsum.

[0005] Therefore, there is an urgent need to develop a gypsum retarder product with excellent retarding performance, little effect on the absolute dry strength of gypsum, low effect on the water requirement of the standard consistency of gypsum, and better adaptability to the application of industrial by-product gypsum. Summary of the invention

[0006] The main technical problem solved by the present invention is to provide a method for preparing a high-performance gypsum retarder. The obtained gypsum retarder can exert an excellent retarding effect at an extremely low dosage, has better adaptability to industrial by-product gypsum, has wide applicability, maintains the corresponding setting time under strong alkaline conditions without significantly increasing the dosage, and has less effect on the absolute dry strength.

[0007] In order to solve the above technical problems, a technical solution adopted by the present invention is: to provide a method for preparing a high-performance gypsum retarder, comprising the following steps:

[0008] S1: Accurately weigh the protein raw material, dissolve it in deionized water, place it in a constant temperature water bath for high temperature denaturation, then adjust it to the enzymatic hydrolysis temperature, add protease for enzymatic hydrolysis, then add alkaline substances to adjust the pH value to neutral, heat it in a boiling water bath to inactivate the enzyme, and wait for the enzymatic hydrolysis solution to cool to room temperature to obtain hydrolyzed protein;

[0009] S2: Stir deionized water, anhydride and hydrolyzed protein in a constant temperature water bath; then add an organic base or an inorganic base to adjust the solution to neutrality, and obtain an intermediate powder by spraying, drying and sieving;

[0010] S3: Add the sieved gypsum reinforcing agent to the intermediate powder, mix well to obtain retarder powder.

[0011] In a preferred embodiment of the present invention, in step S1, the amount of the protein raw material is 10-15 parts, the amount of deionized water is 200-250 parts, the constant temperature water bath temperature is 95-100°C, the high temperature denaturation time is 5-10min, the enzymatic hydrolysis temperature is 45-50°C, the amount of protease is 0.1-2 parts, the enzymatic hydrolysis time is 0.5-2h, and the boiling water bath heating time is 5-20min.

[0012] In a preferred embodiment of the present invention, in step S1, the protein raw material is one or more of animal bone collagen, gelatin protein in animal protein and soy protein in plant protein; the protease is one or more of bromelain, trypsin, glutamic acid protease, papain and subtilisin; the alkaline substance is one or more of sodium hydroxide, calcium oxide and sodium carbonate.

[0013] In a preferred embodiment of the present invention, in step S2, the amount of deionized water is 20-40 parts, the amount of acid anhydride is 15-30 parts, the amount of hydrolyzed protein is 10-20 parts, the constant temperature water bath temperature is 50-100°C, the stirring time is 0.5-24h, and a 120-mesh sieve is used for sieving.

[0014] In a preferred embodiment of the present invention, in step S2, the acid anhydride is one or more of maleic anhydride, itaconic anhydride and dodecenylsuccinic anhydride; the organic base is one of methylamine, ethylamine, dimethylamine, urea, quaternary ammonium base, butyl lithium, lithium diisopropylamide and benzyl lithium; the inorganic base is one of potassium hydroxide, sodium hydroxide and calcium oxide.

[0015] In a preferred embodiment of the present invention, in step S3, the amount of the gypsum enhancer is 1-10 parts, sieved using a 120-mesh sieve, and the amount of the intermediate powder is 100 parts.

[0016] In a preferred embodiment of the present invention, in step S3, the gypsum enhancer is one or more of aluminum sulfate, sodium acrylate and urea.

[0017] The beneficial effects of the present invention are as follows: the present invention points out a method for preparing a high-performance gypsum retarder, the obtained gypsum retarder can exert an excellent retarding effect at an extremely low dosage, has better adaptability to industrial by-product gypsum, has wide applicability, maintains the corresponding setting time under strong alkaline conditions without significantly increasing the dosage, and has less effect on the absolute dry strength. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] The embodiments of the present invention include:

[0020] A method for preparing a high-performance gypsum retarder comprises the following steps:

[0021] S1: Accurately weigh 10-15 parts of protein raw material, dissolve in 200-250 parts of deionized water, place in a constant temperature water bath at 95-100°C for high temperature denaturation for 5-10 minutes, then adjust to the enzymatic hydrolysis temperature of 45-50°C, add 0.1-2 parts of protease for enzymatic hydrolysis for 0.5-2h, then add alkaline substances to adjust the pH value to neutral, heat in a boiling water bath for 5-20 minutes to inactivate the enzyme, and wait for the enzymatic hydrolysis solution to cool to room temperature to obtain hydrolyzed protein;

[0022] The protein raw material is one or more of animal bone collagen, gelatin in animal protein and soy protein in plant protein; the protease is one or more of bromelain, trypsin, glutamic acid protease, papain and subtilisin; the alkaline substance is one or more of sodium hydroxide, calcium oxide and sodium carbonate;

[0023] S2: Stir 20-40 parts of deionized water, 15-30 parts of anhydride and 10-20 parts of hydrolyzed protein in a constant temperature water bath at 50-100°C for 0.5-24 hours; then add an organic base or an inorganic base to adjust the solution to neutrality, and dry it through a 120-mesh sieve by powder spraying to obtain an intermediate powder;

[0024] Wherein, the acid anhydride is one or more of maleic anhydride, itaconic anhydride and dodecenylsuccinic anhydride; the organic base is one of methylamine, ethylamine, dimethylamine, urea, quaternary ammonium base, butyl lithium, lithium diisopropylamide and benzyl lithium; the inorganic base is one of potassium hydroxide, sodium hydroxide and calcium oxide;

[0025] S3: adding 1-10 parts of a gypsum reinforcing agent having passed a 120-mesh sieve to 100 parts of the intermediate powder, and mixing them evenly to obtain a retarder powder;

[0026] Wherein, the gypsum enhancer is one or more of aluminum sulfate, sodium acrylate and urea.

[0027] Embodiment 1

[0028] Accurately weigh 15 parts of animal bone collagen, dissolve it in 200 parts of deionized water, place it in a constant temperature water bath at 95°C for high temperature denaturation for 10 minutes, then adjust the enzymatic temperature to 50°C, add 0.5 parts of trypsin for enzymatic hydrolysis for 1.5 hours, then add an appropriate amount of sodium hydroxide to adjust the pH value to neutral, heat it in a boiling water bath for 20 minutes to inactivate the enzyme, and wait for the enzymatic solution to cool to room temperature to obtain hydrolyzed protein; 20 parts of deionized water, 15 parts of itaconic anhydride and 10 parts of hydrolyzed protein are stirred in a constant temperature water bath at 65°C for 2 hours; then add an appropriate amount of quaternary ammonium alkali to adjust the solution to neutrality, and obtain an intermediate powder by powder spray drying and passing through a 120-mesh sieve; 1 part of gypsum enhancer passing through a 120-mesh sieve is added to 100 parts of the intermediate powder, and mixed evenly to obtain a retarder powder.

[0029] Embodiment 2

[0030] Accurately weigh 10 parts of gelatin protein, dissolve it in 250 parts of deionized water, place it in a constant temperature water bath at 95°C for high temperature denaturation for 5 minutes, then adjust the enzymatic hydrolysis temperature to 45°C, add 1 part of papain for enzymatic hydrolysis for 2 hours, then add an appropriate amount of sodium hydroxide to adjust the pH value to neutral, heat it in a boiling water bath for 20 minutes to inactivate the enzyme, and wait for the enzymatic hydrolysis solution to cool to room temperature to obtain hydrolyzed protein; 30 parts of deionized water, 20 parts of itaconic anhydride and 15 parts of hydrolyzed protein are stirred in a constant temperature water bath at 70°C for 3 hours; then add an appropriate amount of butyl lithium to adjust the solution to neutrality, and obtain an intermediate powder by powder spray drying and passing through a 120-mesh sieve; 2 parts of aluminum sulfate passing through a 120-mesh sieve are added to 100 parts of the intermediate powder, and mixed evenly to obtain a retarder powder.

[0031] The synthetic products of Example 1 and Example 2 were compared with imported retarder A and imported retarder B in a desulfurized building gypsum lightweight plastering ratio in terms of setting time, absolute dry strength, and table fluidity. The plastering ratio contained 0% and 2% calcium hydroxide, and the amount of retarder was adjusted to make the setting time close.

[0032] The test results are as follows: Table 1: Performance comparison of retarders in plastering gypsum with industrial by-product desulfurized gypsum and calcium hydroxide:

[0033]

[0034]

[0035] The products of Example 1 and Example 2, in the selected desulfurized building gypsum plastering formula, whether the calcium hydroxide dosage is 0% or 2%, the dosage when the setting time is extended to 120-140min is much lower than the dosage of imported products on the current market, and the absolute dry strength is higher under the same dosage. It shows that the example product retarder has higher retarding efficiency in gypsum plastering and has less effect on gypsum strength. And the jumping table fluidity of plastering gypsum is not significantly different from that of imported retarders.

[0036] In summary, the present invention provides a method for preparing a high-performance gypsum retarder. The obtained gypsum retarder can exert an excellent retarding effect at an extremely low dosage, has better adaptability to industrial by-product gypsum, has wide applicability, maintains the corresponding setting time under strong alkaline conditions without significantly increasing the dosage, and has less effect on the absolute dry strength.

[0037] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for preparing a high-performance gypsum retarder, characterized in that: The steps include: S1: Accurately weigh the protein raw material, dissolve it in deionized water, place it in a constant temperature water bath for high temperature denaturation, then adjust it to the enzymatic hydrolysis temperature, add protease for enzymatic hydrolysis, then add alkaline substances to adjust the pH value to neutral, heat it in a boiling water bath to inactivate the enzyme, and wait for the enzymatic hydrolysis solution to cool to room temperature to obtain hydrolyzed protein; S2: Stir deionized water, anhydride and hydrolyzed protein in a constant temperature water bath; then add an organic base or an inorganic base to adjust the solution to neutrality, and obtain an intermediate powder by spraying, drying and sieving; S3: Add the sieved gypsum reinforcing agent to the intermediate powder, mix well to obtain retarder powder.

2. The method for preparing a high-performance gypsum retarder according to claim 1, characterized in that: In step S1, the amount of the protein raw material is 10-15 parts, the amount of deionized water is 200-250 parts, the constant temperature water bath temperature is 95-100°C, the high temperature denaturation time is 5-10 minutes, the enzymatic hydrolysis temperature is 45-50°C, the amount of the protease is 0.1-2 parts, the enzymatic hydrolysis time is 0.5-2 hours, and the boiling water bath heating time is 5-20 minutes.

3. The method for preparing a high-performance gypsum retarder according to claim 1, characterized in that: In step S1, the protein raw material is one or more of animal bone collagen, gelatin protein in animal protein and soy protein in plant protein; the protease is one or more of bromelain, trypsin, glutamic acid protease, papain and subtilisin; the alkaline substance is one or more of sodium hydroxide, calcium oxide and sodium carbonate.

4. The method for preparing a high performance gypsum retarder according to claim 1, characterized in that: In step S2, the amount of deionized water is 20-40 parts, the amount of acid anhydride is 15-30 parts, the amount of hydrolyzed protein is 10-20 parts, the temperature of the constant temperature water bath is 50-100° C., the stirring time is 0.5-24h, and a 120-mesh sieve is used for sieving.

5. The method for preparing a high performance gypsum retarder according to claim 1, characterized in that: In step S2, the acid anhydride is one or more of maleic anhydride, itaconic anhydride and dodecenylsuccinic anhydride; the organic base is one of methylamine, ethylamine, dimethylamine, urea, quaternary ammonium base, butyl lithium, lithium diisopropylamide and benzyl lithium; the inorganic base is one of potassium hydroxide, sodium hydroxide and calcium oxide.

6. The method for preparing a high performance gypsum retarder according to claim 1, characterized in that: In step S3, the amount of the gypsum enhancer is 1-10 parts, sieved with a 120-mesh sieve, and the amount of the intermediate powder is 100 parts.

7. The method for preparing a high performance gypsum retarder according to claim 1, characterized in that: In step S3, the gypsum enhancer is one or more of aluminum sulfate, sodium acrylate and urea.

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