Partial dry-process fresh semi-hydrated phosphogypsum cementing material

Abstract

The invention relates to the technical field of gypsum materials, in particular to a partial dry-process fresh semi-hydrated phosphogypsum cementing material, the main crystal of the partial dry-process fresh semi-hydrated phosphogypsum cementing material is alpha-like, the partial dry-process fresh semi-hydrated phosphogypsum cementing material comprises 3-5% of an auxiliary agent, 4-6% of a light material and the balance of fresh semi-hydrated phosphogypsum, and the auxiliary agent, the light material and the fresh semi-hydrated phosphogypsum are fully stirred and mixed to prepare the partial dry-process fresh semi-hydrated phosphogypsum cementing material. The partial dry-process fresh semi-hydrated ardealite cementing material can be prepared. Fresh semi-hydrated phosphogypsum obtained by a wet-process phosphoric acid semi-hydrated method or a dihydrate semi-hydrated method is used as a main raw material, an auxiliary agent with an optimized ratio is used as an auxiliary material, the obtained gypsum cementing material can be extruded up and down or pressed through a mold to form gypsum hardened bodies such as gypsum hollow blocks, hollow battens, high-strength plates, bricks, curbs and the like; the method has the characteristics of simple process, fast forming and high quality; moreover, operations such as drying and maintenance are not needed during production, so that the production cost can be greatly reduced, and the production efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of gypsum materials, in particular to a componentized dry-process fresh hemihydrate phosphogypsum cementitious material. Background Art

[0002] Phosphogypsum is fresh hemihydrate phosphogypsum waste residue discharged during the production of wet-process phosphoric acid (phosphoric acid) dihydrate hemihydrate or hemihydrate. It typically appears dark gray or off-white. Its primary components are calcium sulfate and its hydration products, with CaSO₄·2H₂O making up a significant portion. It also contains impurities such as phosphates, fluorides, and organic matter. In recent years, China's annual phosphogypsum emissions have exceeded 80 million tons. Due to insufficient resource utilization, the massive accumulation of phosphogypsum not only encroaches on land resources but also poses a serious threat to the aquatic environment due to the water-soluble phosphorus pentoxide and fluorine it contains, posing a significant ecological and environmental risk. There is an urgent need to expand the utilization of phosphogypsum and promote its use in new building materials and other fields.

[0003] Patent application number 202411213961.0 discloses a modified phosphogypsum lightweight insulating building block and its preparation method, achieving resource-saving and harmless utilization of phosphogypsum. However, the block preparation process requires additional water and a long period of curing, making the process complex and increasing production costs. Based on this, a componentized dry-process fresh hemihydrate phosphogypsum cementitious material is proposed. Summary of the Invention

[0004] In response to the shortcomings of the existing technology, the present invention provides a componentized dry-process fresh hemihydrated phosphogypsum cementitious material, which uses fresh hemihydrated phosphogypsum as the main raw material and is supplemented with auxiliary agents with optimized proportions. The obtained gypsum cementitious material can be directly used to produce gypsum hollow blocks, which has the characteristics of simple process, fast molding and high quality.

[0005] To achieve the above object, the present invention provides the following technical solution: a componentized dry fresh hemihydrate phosphogypsum cementitious material, the crystals of which are α-type, and which comprises, by mass percentage, 3-5% of an additive, 4-6% of a lightweight material, and the balance being fresh hemihydrate phosphogypsum.

[0006] Preferably, the auxiliary agent is selected from bentonite and phosphate.

[0007] Preferably, the mass ratio of the bentonite to the phosphate is 1:2.

[0008] Preferably, the lightweight material is selected from perlite and fly ash.

[0009] Preferably, the mass ratio of perlite to fly ash is (1-2): (1-3).

[0010] Preferably, the free water content in the fresh hemihydrate phosphogypsum is 20±3%.

[0011] The invention provides a preparation method of a componentized dry-process fresh hemihydrate phosphogypsum cementitious material. The method comprises fully stirring and mixing an auxiliary agent, a lightweight material and fresh hemihydrate phosphogypsum to prepare the componentized dry-process fresh hemihydrate phosphogypsum cementitious material.

[0012] The present invention also provides an application of a componentized dry-process fresh hemihydrate phosphogypsum cementitious material, which is applied to gypsum blocks, gypsum boards and gypsum bricks.

[0013] The present invention provides a componentized dry-process fresh hemihydrate phosphogypsum cementitious material, which has the following beneficial effects compared with the prior art:

[0014] The present invention uses fresh hemihydrate phosphogypsum as the main raw material and supplements with an optimized ratio of additives. The obtained gypsum cementitious material is subjected to dry extrusion or press molding to produce gypsum hollow blocks, gypsum boards, and bricks. The process is simple, the molding is fast, and the quality is high. Moreover, no drying, curing, or other operations are required during production, which can significantly reduce production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0016] Figure 1 Schematic diagrams of two extrusion molding processes of the dry process fresh hemihydrate phosphogypsum cementitious material of the present invention;

[0017] Figure 2 This is an electron microscope image of a gypsum hollow block prepared by using the dry process fresh hemihydrate phosphogypsum cementitious material in Example 5 of the present invention. DETAILED DESCRIPTION

[0018] The following examples illustrate the implementation methods of the present application in detail, so that the implementation process of how the present application applies technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0019] Example 1

[0020] A componentized dry-process fresh hemihydrate phosphogypsum cementitious material has α-type crystals and comprises, by mass percentage, 3% of an auxiliary agent, 4% of a lightweight material, and the remainder being fresh hemihydrate phosphogypsum, with a free water content of 20±3%.

[0021] The above-mentioned additives are bentonite and phosphate, and the mass ratio of bentonite to phosphate is 1:2.

[0022] The lightweight materials are perlite and fly ash, and the mass ratio of perlite to fly ash is 1:1.

[0023] The preparation method of the componentized dry-process fresh hemihydrate phosphogypsum cementitious material comprises fully stirring and mixing the auxiliary agent, the lightweight material and the fresh hemihydrate phosphogypsum to obtain the product.

[0024] Example 2

[0025] A componentized dry-process fresh hemihydrate phosphogypsum cementitious material has α-type crystals and comprises, by mass percentage, 5% of an auxiliary agent, 6% of a lightweight material, and the remainder being fresh hemihydrate phosphogypsum, with a free water content of 20±2%.

[0026] The above-mentioned additives are bentonite and phosphate, and the mass ratio of bentonite to phosphate is 1:2.

[0027] The lightweight materials are perlite and fly ash, and the mass ratio of perlite to fly ash is 2:1.

[0028] The preparation method of the componentized dry-process fresh hemihydrate phosphogypsum cementitious material comprises fully stirring and mixing the auxiliary agent, the lightweight material and the fresh hemihydrate phosphogypsum to obtain the product.

[0029] Example 3

[0030] A componentized dry-process fresh hemihydrate phosphogypsum cementitious material has α-type crystals and comprises, by mass percentage, 3% of an auxiliary agent, 4% of a lightweight material, and the remainder being fresh hemihydrate phosphogypsum, with a free water content of 20±2%.

[0031] The above-mentioned additives are bentonite and phosphate, and the mass ratio of bentonite to phosphate is 1:2.

[0032] The lightweight materials are perlite and fly ash, and the mass ratio of perlite to fly ash is 1:3.

[0033] The preparation method of the componentized dry-process fresh hemihydrate phosphogypsum cementitious material comprises fully stirring and mixing the auxiliary agent, the lightweight material and the fresh hemihydrate phosphogypsum to obtain the product.

[0034] Example 4

[0035] A componentized dry-process fresh hemihydrate phosphogypsum cementitious material has α-type crystals and comprises, by mass percentage, 5% of an additive, 4% of a lightweight material, and the remainder being fresh hemihydrate phosphogypsum, with a free water content of 20±3%.

[0036] The above-mentioned additives are bentonite and phosphate, and the mass ratio of bentonite to phosphate is 1:2.

[0037] The lightweight materials are perlite and fly ash, and the mass ratio of perlite to fly ash is 1:1.

[0038] The preparation method of the componentized dry-process fresh hemihydrate phosphogypsum cementitious material comprises fully stirring and mixing the auxiliary agent, the lightweight material and the fresh hemihydrate phosphogypsum to obtain the product.

[0039] Example 5

[0040] A componentized dry-process fresh hemihydrate phosphogypsum cementitious material has α-type crystals and comprises, by mass percentage, 4% of an auxiliary agent, 5% of a lightweight material, and the remainder being fresh hemihydrate phosphogypsum, with a free water content of 20±2%.

[0041] The above-mentioned additives are bentonite and phosphate, and the mass ratio of bentonite to phosphate is 1:2.

[0042] The lightweight materials are perlite and fly ash, and the mass ratio of perlite to fly ash is 1:1.

[0043] The preparation method of the componentized dry-process fresh hemihydrate phosphogypsum cementitious material comprises fully stirring and mixing the auxiliary agent, the lightweight material and the fresh hemihydrate phosphogypsum to obtain the product.

[0044] Comparative Example 1

[0045] A componentized dry-process fresh hemihydrate phosphogypsum cementitious material has α-type crystals and comprises, by mass percentage, 4% of an auxiliary agent, 5% of a lightweight material, and the remainder being fresh hemihydrate phosphogypsum, with a free water content of 20±3%.

[0046] The above-mentioned additives are bentonite and phosphate, and the mass ratio of bentonite to phosphate is 1:1.

[0047] The lightweight materials are perlite and fly ash, and the mass ratio of perlite to fly ash is 1:1.

[0048] The preparation method of the componentized dry-process fresh hemihydrate phosphogypsum cementitious material comprises fully stirring and mixing the auxiliary agent, the lightweight material and the fresh hemihydrate phosphogypsum to obtain the product.

[0049] Comparative Example 2

[0050] A componentized dry-process fresh hemihydrate phosphogypsum cementitious material has α-type crystals and comprises, by mass percentage, 4% of an auxiliary agent, 5% of a lightweight material, and the remainder being fresh hemihydrate phosphogypsum, with a free water content of 20±3%.

[0051] The above-mentioned additives are bentonite and phosphate, and the mass ratio of bentonite to phosphate is 1:3.

[0052] The lightweight materials are perlite and fly ash, and the mass ratio of perlite to fly ash is 1:1.

[0053] The preparation method of the componentized dry-process fresh hemihydrate phosphogypsum cementitious material comprises fully stirring and mixing the auxiliary agent, the lightweight material and the fresh hemihydrate phosphogypsum to obtain the product.

[0054] Quality Inspection

[0055] 1. The componentized dry-process fresh hemihydrate phosphogypsum cementitious material obtained in Example 5 was injected into a mold and extruded for 5 minutes before forming. After 2 hours, a hollow gypsum block with dimensions of 600 × 250 × 200 mm was obtained. The hollow gypsum blocks were tested in accordance with the JC / T698-2010 standard. The specific test results are shown in the following table.

[0056] Table 1 Gypsum hollow blocks

[0057]

[0058]

[0059] 2. The fracture load test was performed on the hollow gypsum blocks made from the componentized dry-process fresh hemihydrate phosphogypsum cementitious materials in Examples 1-4 and Comparative Examples 1-2 according to the method in 1. The specific results are shown in the following table.

[0060] Table 2 Fracture load

[0061] category Breaking load (N) Example 1 4312 Example 2 4285 Example 3 4303 Example 4 4290 Comparative Example 1 3124 Comparative Example 2 3058

[0062] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A componentized dry fresh hemihydrate phosphogypsum cementitious material, the crystals are α-type, characterized in that: Calculated by mass percentage, it includes 3-5% of auxiliary agent, 4-6% of lightweight material, and the balance is fresh hemihydrate phosphogypsum.

2. The componentized dry fresh hemihydrate phosphogypsum cementitious material according to claim 1, characterized in that: The auxiliary agent is selected from bentonite and phosphate.

3. The componentized dry fresh hemihydrate phosphogypsum cementitious material according to claim 2, characterized in that: The mass ratio of the bentonite to the phosphate is 1:

2.

4. The componentized dry fresh hemihydrate phosphogypsum cementitious material according to claim 1, characterized in that: The lightweight material is selected from perlite and fly ash.

5. The componentized dry fresh hemihydrate phosphogypsum cementitious material according to claim 4, characterized in that: The mass ratio of the perlite to the fly ash is (1-2):(1-3).

6. The componentized dry fresh hemihydrate phosphogypsum cementitious material according to claim 1, characterized in that: The free water content in the fresh hemihydrate phosphogypsum is 20±3%.

7. The method for preparing a componentized dry fresh hemihydrate phosphogypsum cementitious material according to any one of claims 1 to 6, characterized in that: The auxiliary agent, lightweight material and fresh semi-hydrated phosphogypsum are fully stirred and mixed to obtain componentized dry-process fresh semi-hydrated phosphogypsum cementitious material.

8. Use of the componentized dry fresh hemihydrate phosphogypsum cementitious material according to claims 1-6 or the componentized dry fresh hemihydrate phosphogypsum cementitious material prepared by the preparation method according to claim 7, characterized in that: For use in gypsum blocks, gypsum boards and gypsum bricks.

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