Functional gypsum for cement and preparation method thereof

Abstract

The invention relates to functional gypsum for cement and a preparation method thereof, the functional gypsum comprises the following raw materials by weight: 95-99 parts of a material A, 1-5 parts of a solid waste, and 0.1-2 parts of a gypsum quality improver, the material A is one or a combination of more of phosphogypsum, fluorgypsum and desulfurized gypsum, and the gypsum quality improver is a macromolecular material. According to the invention, the solid waste resource is used as a main material, so that the solid waste resource is recycled, the solid waste resource is utilized, and the treated solid waste resource can be used for manufacturing the cement, so that the recycling is realized, the environmental protection property is improved, and the comprehensive utilization of the solid waste is realized; in addition, water-soluble phosphorus and water-soluble fluorine in the phosphogypsum are digested, a stable retarding duration effect is achieved, the dispersity of the gypsum in the cement grinding process is improved, the synchronization performance of the gypsum participating in hydration subsequently is enhanced, the low-grade admixture can be driven to participate in hydration, and the proportion of the low-grade admixture can be increased.

Description

Technical Field

[0001] The invention relates to gypsum for cement, in particular to functional gypsum for cement and a preparation method thereof. Background Art

[0002] Phosphogypsum is an industrial waste residue discharged from the wet production of phosphoric acid. At present, the annual discharge of phosphogypsum in my country has exceeded 150 million tons. The resource utilization of phosphogypsum is mainly used to produce gypsum cementitious materials and as a cement retarder. However, the harmful impurities such as phosphorus and fluorine contained in phosphogypsum have a certain adverse effect on the application performance, so phosphogypsum needs to be pretreated. Pretreatment not only increases the application cost and utilization difficulty, but also the performance after treatment is still inferior to natural gypsum, which ultimately leads to a very low utilization rate of phosphogypsum.

[0003] CN201910274988.3: A phosphogypsum-based cement concrete mortar is disclosed, characterized in that it includes phosphogypsum, a first cement clinker, an alkaline material, standard sand, a first water agent, a second water agent and a water reducing agent, wherein the alkaline material is a mixture formed by mixing the second cement clinker with one of mineral powder, fly ash and lime; the phosphogypsum, the first cement clinker and the first water agent are mixed and pre-treated by ball milling at room temperature to obtain phosphogypsum slurry, the phosphogypsum slurry is aged to obtain modified phosphogypsum slurry, and the modified phosphogypsum slurry is mixed with the alkaline material, standard sand, the second water agent and the water reducing agent and stirred to obtain supersulfur cement mortar. The present invention has the technical effect of being able to remove impurities from phosphorus and fluorine compounds and thus improve the early strength and density of concrete.

[0004] CN92107830.7 discloses a method for preparing pozzolanic phosphogypsum cement, which comprises mixing phosphogypsum, coal gangue powder and slaked lime, mixing them by wet method, neutralizing them and forming them into hollow brick-shaped raw material blanks, drying and stacking them in a rotary kiln or a flint kiln with a waste heat drying chamber, stacking the brick blanks without internal fuel, which account for 5-10% of the total raw material blanks, in the middle of the kiln section, roasting, heat preservation and rapid cooling to form mature blanks, and then grinding them together with slag, ordinary cement and pozzolanic mixed material ingredients into hollow brick-shaped raw material blanks with a specific surface area greater than 6000cm 2 / g, SO3 content 10-20%

[0005] CN201210023107.9: A method for producing cement and sulfuric acid by calcining anhydrite, comprising the following steps: (1) crushing the anhydrite and drying it to obtain hemihydrate gypsum; (2) mixing the obtained hemihydrate gypsum, barite, sand and coal, placing the mixture in a preheater and heating it to 850-950°C; then placing the mixture in a rotary kiln and heating it to 1000-1450°C, keeping the mixture warm for 2-5 hours to obtain kiln gas and solid materials, and sending the obtained kiln gas into a preheater to preheat the raw materials and reduce the temperature of the kiln gas at the same time; (3) cooling the obtained solid materials to 30-90°C, adding a cement retarder, grinding the materials and obtaining a cement product; (4) collecting the kiln gas in the preheater and the rotary kiln, removing dust, purifying and drying the kiln gas, and oxidizing the sulfur dioxide in the kiln gas into sulfur trioxide under the action of a vanadium catalyst, and absorbing and converting the sulfur trioxide into sulfur trioxide using concentrated sulfuric acid having a mass fraction of ≥98% to generate sulfuric acid. The cement produced by the invention contains barium, has high density and has radiation resistance, and is particularly suitable for nuclear power plant projects or the construction of some bunkers and air-raid shelters.

[0006] Although the main components of phosphogypsum are the same as those of natural gypsum, the impurities in phosphogypsum have a certain adverse effect on the application performance, and generally need to be pre-treated before use. However, the existing technology for pre-treatment of phosphogypsum increases the application cost and difficulty of utilization, such as water washing, which not only consumes a lot of water resources, but also causes secondary pollution. Summary of the invention

[0007] In order to solve the above technical problems, the present invention provides a functional gypsum for cement and a preparation method thereof.

[0008] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0009] A functional gypsum for cement, comprising the following raw materials in parts by weight:

[0010] 95-99 parts of material A, 1-5 parts of solid waste, and 0.1-2 parts of gypsum quality improver. Material A is a combination of one or more of phosphogypsum, fluorgypsum and desulfurized gypsum. The gypsum quality improver is a macromolecular material.

[0011] As a further improvement, the phosphogypsum, fluorgypsum and desulfurized gypsum are industrial by-product gypsums produced by chemical plants, power plants and other enterprises.

[0012] As a further improvement, the gypsum quality improver is in liquid or powder form.

[0013] As a further improvement, a method for preparing functional gypsum for cement comprises the following steps:

[0014] Prepare raw materials and divide them into material A, material B and material C, wherein material B is solid waste containing calcium hydroxide, material C is a gypsum quality improver, and the water content of material A is controlled at 10-17%;

[0015] Mix material A and material B evenly;

[0016] Then mix with gypsum quality improver;

[0017] The preparation is completed after aging in pile for 24-30 hours with the room temperature being less than or equal to 40°C.

[0018] The gypsum quality improver is prepared by the following method:

[0019] The protein product is used as a raw material, an aqueous solution of the protein product is heated and stirred, and a phosphorylation reagent is added; the pH is adjusted to alkaline, the temperature is increased, and a phosphorylation reaction is performed; after the reaction is completed, the pH is adjusted to neutral to obtain a phosphorylated protein stock solution; the phosphorylated protein stock solution is dialyzed to remove the phosphorylation reagent that has not reacted with the protein product, and the phosphorylated protein-based gypsum quality improver is obtained after drying.

[0020] As a further improvement, the gypsum quality improver is prepared by the following method:

[0021] The invention comprises the following raw materials in parts by weight:

[0022] Itaconic acid-p-aminostyrene phosphoric acid copolymer 30-50 parts, organic acid salt 13-20 parts, aminosulfonate 5-25 parts, acrylate 10-20 parts;

[0023] and adding 1-5 parts of a catalyst and 1-5 parts of a polymerization inhibitor to carry out an amidation reaction at a reaction temperature of 100-110° C. and a reflux reaction time of 4-6 hours to form an intermediate product;

[0024] The aqueous solution formed by the intermediate product, olefin sulfonic acid and water is used as a base material, a chain transfer agent is added, and an initiator, a reducing agent and an acrylic acid monomer are respectively added dropwise, and a free radical copolymerization reaction is carried out at room temperature. The dropping time is controlled to be 1-1.5 hours. After the dropping is completed, the reaction is continued for 1.5-2 hours to obtain a copolymer, and an alkaline substance is added to neutralize it to a pH of 6-8 to obtain a gypsum quality improver.

[0025] As a further improvement, the protein product is collagen hydrolyzate from leather waste, animal hair hydrolyzate, industrial gelatin, bone glue or soy protein.

[0026] As a further improvement, the phosphorylation reaction is carried out at a temperature of 40-60° C. and for a time of 4-10 h.

[0027] As a further improvement, the dialysis is to dialyze the phosphorylated protein stock solution against distilled water at 5° C. for 50 hours.

[0028] Compared with the prior art, the present invention has the following beneficial technical effects:

[0029] Through the specific gypsum quality improver, the effect of effectively stabilizing the setting time of cement can be achieved, which can effectively reduce the application cost. The raw materials used are all conventional chemical raw materials, the quality of the raw materials is stable and controllable, the process is simple, the entire process can be flow-lined, and the control difficulty is small. Therefore, the quality of the gypsum quality improver product is stable and controllable. The gypsum quality improver is added to gypsum, and the functional gypsum produced is applied to cement. The setting time of cement presents a continuous and stable state, which can better adjust the setting time of cement and improve the strength quality of cement. Using solid waste resources as the main material realizes the recycling of solid waste resources. It not only utilizes solid waste resources, but also can use the treated solid waste resources to make cement, realizing recycling, improving environmental protection, and realizing the comprehensive utilization of solid waste. DETAILED DESCRIPTION

[0031] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0032] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection. It can be a mechanical connection or an electrical connection. It can be directly connected or indirectly connected through an intermediate medium. It can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] Embodiment 1

[0034] A functional gypsum for cement is composed of the following raw materials in parts by weight: 96 parts of phosphogypsum, 3.3 parts of carbide slag, and 0.7 parts of a gypsum quality improver, wherein the gypsum quality improver is a liquid material.

[0035] A method for preparing functional gypsum for cement comprises the following steps:

[0036] Prepare raw materials and divide them into material A, material B and material C, material B is solid waste containing calcium hydroxide, material C is a gypsum quality improver, and the water content of material A is controlled at 15%;

[0037] Mix material A and material B evenly;

[0038] Then mix with C material gypsum quality improver;

[0039] The preparation was completed after aging in pile for 24 hours at room temperature of 40°C.

[0040] The gypsum quality improver is prepared by the following method:

[0041] The protein product is used as a raw material, an aqueous solution of the protein product is heated and stirred, and a phosphorylation reagent is added; the pH is adjusted to alkaline, the temperature is increased, and a phosphorylation reaction is performed; after the reaction is completed, the pH is adjusted to neutral to obtain a phosphorylated protein stock solution; the phosphorylated protein stock solution is dialyzed to remove the phosphorylation reagent that has not reacted with the protein product, and the phosphorylated protein-based gypsum powder quality improver is obtained after drying.

[0042] The phosphorylation reaction is carried out at a temperature of 40-60° C. and for a time of 4-10 h.

[0043] The dialysis is performed by dialyzing the phosphorylated protein stock solution against distilled water at 5° C. for 50 hours.

[0044] Embodiment 2

[0045] A functional gypsum for cement is composed of the following raw materials in parts by weight: 65 parts of phosphogypsum, 32.9 parts of fluorinated gypsum, 2 parts of carbide slag, and 0.1 part of a gypsum quality improver, wherein the gypsum quality improver is a liquid material.

[0046] A method for preparing functional gypsum for cement comprises the following steps:

[0047] Prepare raw materials and divide them into material A, material B and material C, material B is solid waste containing calcium hydroxide, material C is a gypsum quality improver, and the water content of material A is controlled at 12%;

[0048] Mix material A and material B evenly;

[0049] Then mix with C material gypsum quality improver;

[0050] The preparation was completed after aging in pile for 26 hours at room temperature of 35°C.

[0051] The gypsum quality improver is prepared by the following method:

[0052] The invention comprises the following raw materials in parts by weight:

[0053] Itaconic acid-p-aminostyrene phosphoric acid copolymer 30-50 parts, organic acid salt 13-20 parts, aminosulfonate 5-25 parts, acrylate 10-20 parts;

[0054] and adding 1-5 parts of a catalyst and 1-5 parts of a polymerization inhibitor to carry out an amidation reaction at a reaction temperature of 100-110° C. and a reflux reaction time of 4-6 hours to form an intermediate product;

[0055] The aqueous solution formed by the intermediate product, olefin sulfonic acid and water is used as a base material, a chain transfer agent is added, and an initiator, a reducing agent and an acrylic acid monomer are respectively added dropwise, and a free radical copolymerization reaction is carried out at room temperature. The dropping time is controlled to be 1-1.5 hours. After the dropping is completed, the reaction is continued for 1.5-2 hours to obtain a copolymer, and an alkaline substance is added to neutralize it to a pH of 6-8 to obtain a liquid gypsum quality improver.

[0056] Embodiment 3

[0057] A functional gypsum for cement is composed of the following raw materials in parts by weight: 50 parts of phosphogypsum, 21 parts of fluorinated gypsum, 26 parts of desulfurized gypsum, 1 part of calcium carbide slag, and 2 parts of a gypsum quality improver, wherein the gypsum quality improver is a powder material.

[0058] A method for preparing functional gypsum for cement comprises the following steps:

[0059] Prepare raw materials and divide them into material A, material B and material C, material B is solid waste containing calcium hydroxide, material C is a gypsum quality improver, and the water content of material A is controlled at 15%;

[0060] Mix material A and material B evenly;

[0061] Then mix with C material gypsum quality improver;

[0062] The preparation is completed after aging in pile for 30 hours with the room temperature being less than or equal to 30°C.

[0063] The gypsum quality improver is prepared by the following method:

[0064] The protein product is used as a raw material, an aqueous solution of the protein product is heated and stirred, and a phosphorylation reagent is added; the pH is adjusted to alkaline, the temperature is increased, and a phosphorylation reaction is performed; after the reaction is completed, the pH is adjusted to neutral to obtain a phosphorylated protein stock solution; the phosphorylated protein stock solution is dialyzed to remove the phosphorylation reagent that has not reacted with the protein product, and the phosphorylated protein-based gypsum quality modifier is obtained after drying.

[0065] The protein product is animal hair hydrolyzate. The phosphorylation reaction temperature is 40-60° C. and the time is 4-10 hours. The dialysis is to dialyze the phosphorylated protein stock solution with distilled water at 5° C. for 50 hours.

[0066] Comparative Example

[0067] The gypsum used is natural gypsum.

[0068] Example

[0069] The gypsum used is the functional gypsum for cement prepared by this patent

[0070] The gypsum prepared in each embodiment and comparative example was added to the (PO42.5) silicate cement preparation material at a weight ratio of 5% to prepare cement. The cement prepared by the gypsum in the embodiment and comparative example was tested, and its various performance indicators all met the national standard GB175-2023 "General Portland Cement", wherein the setting time and strength test of cement were tested in accordance with the standard test of GB / T17671-1999 "Test Method for Strength of Cement Mortar (ISO Method)"; the fluidity of cement was tested in accordance with the standard test of GB / T8077-2012 "Test Method for Homogeneity of Concrete Admixtures". The test results are shown in Table 1.

[0071]

[0072] It should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. However, any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A functional gypsum for cement, characterized in that: It is composed of the following raw materials in parts by weight: 95-99 parts of material A, 1-5 parts of solid waste, and 0.1-2 parts of gypsum quality improver. Material A is a combination of one or more of phosphogypsum, fluorgypsum and desulfurized gypsum. The gypsum quality improver is a macromolecular material.

2. The functional gypsum for cement according to claim 1, characterized in that: The phosphogypsum, fluorgypsum and desulfurized gypsum are industrial by-product gypsums produced by chemical plants, power plants and other enterprises.

3. The functional gypsum for cement according to claim 1, characterized in that: The gypsum quality improver is in liquid or powder form.

4. A method for preparing functional gypsum for cement, characterized in that: The following steps are involved: Prepare raw materials and divide them into material A, material B and material C, wherein material B is solid waste containing calcium hydroxide or calcium oxide, material C is a gypsum quality improver, and the water content of material A is controlled at 10-17%; Mix material A and material B evenly; Then mix with gypsum quality improver; The preparation is completed after aging in pile for 24-30 hours with the room temperature less than or equal to 40°C.

5. The method for preparing functional gypsum for cement according to claim 4, characterized in that: The gypsum quality improver is prepared by the following method: Using the protein product as a raw material, heating and stirring the aqueous solution of the protein product, adding a phosphorylation reagent; adjusting the pH to alkaline, heating and heating to carry out a phosphorylation reaction; after the reaction is completed, adjusting the pH to neutral to obtain a phosphorylated protein stock solution; The phosphorylated protein stock solution is dialyzed to remove the phosphorylation reagent that has not reacted with the protein product, and the phosphorylated protein-based gypsum quality improver is obtained after drying.

6. The method for preparing functional gypsum for cement according to claim 4, characterized in that: The gypsum quality improver is prepared by the following method: The invention comprises the following raw materials in parts by weight: Itaconic acid-p-aminostyrene phosphoric acid copolymer 30-50 parts, organic acid salt 13-20 parts, aminosulfonate 5-25 parts, acrylate 10-20 parts; and adding 1-5 parts of a catalyst and 1-5 parts of a polymerization inhibitor to carry out an amidation reaction at a reaction temperature of 100-110° C. and a reflux reaction time of 4-6 hours to form an intermediate product; The aqueous solution formed by the intermediate product, olefin sulfonic acid and water is used as a base material, a chain transfer agent is added, and an initiator, a reducing agent and an acrylic acid monomer are respectively added dropwise, and a free radical copolymerization reaction is carried out at room temperature. The dropping time is controlled to be 1-1.5 hours. After the dropping is completed, the reaction is continued for 1.5-2 hours to obtain a copolymer, and an alkaline substance is added to neutralize it to a pH of 6-8 to obtain a gypsum quality improver.

7. The method for preparing functional gypsum for cement according to claim 5, characterized in that: The protein product is collagen hydrolyzate of leather waste, animal hair hydrolyzate, industrial gelatin, bone glue or soy protein.

8. The method for preparing functional gypsum for cement according to claim 5, characterized in that: The phosphorylation reaction is carried out at a temperature of 40-60° C. and for a time of 4-10 h.

9. The method for preparing functional gypsum for cement according to claim 4, characterized in that: The dialysis is performed by dialyzing the phosphorylated protein stock solution against distilled water at 5° C. for 50 hours.

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