CN1792985A

CN1792985A - Gypsum mine plastering material and preparation process thereof

Info

Publication number: CN1792985A
Application number: CNA2005101205141A
Authority: CN
Inventors: 姜洪义
Original assignee: Wuhan University of Technology WUT
Current assignee: Wuhan University of Technology WUT
Priority date: 2005-12-23
Filing date: 2005-12-23
Publication date: 2006-06-28
Anticipated expiration: 2025-12-23
Also published as: CN100363295C

Abstract

A plastering material is proportionally prepared from gypsum are tailings, slag powder, trigger, early-strengthening agent, redispersible colloid powder, and water preserving agent through proportional mixing.

Description

Gypsum tailing plastering material and preparation method thereof

Technical Field

The invention belongs to the technical field of novel building materials, and particularly relates to a method for manufacturing a building plastering material by using gypsum tailings.

Background

Gypsum tailings refer to gypsum ore with a dihydrate gypsum content of less than 50%, which is an industrial waste due to the various impurities that it contains and cannot be used to calcine plaster of paris. At present, a large amount of large gypsum ores exist, so that land is occupied, production is influenced, and the environment is polluted. Therefore, the recycling of gypsum tailings has attracted attention.

In the early 80 s, the study on the recycling of gypsum tailings was carried out. The preparation method comprises the following steps: calcining the gypsum tailings at high temperature (more than 800 ℃) to convert dihydrate gypsum into anhydrous gypsum, and then adding cement and other additives. However, the water resistance of the product is poor and the product is frosted, so that the product cannot enter the practical application stage. The reason for this preliminary analysis by study is: (1) the calcination temperature is too high, so that the initial water filling space of the mineralized body is too small, and the structural stability of the hardened body is poor; (2) the feldspar is calcined at high temperature, the crystal structure is damaged, and Na is generated⁺、K⁺Ions are activated and easily react with SO₄ ^2-And combining to generate mirabilite. Therefore,the test of calcining gypsum tailings to prepare a cementitious material has not been successful.

Disclosure of Invention

The invention aims to provide a gypsum tailing plastering material with low cost and a preparation method thereof.

In order to achieve the purpose, the technical scheme of the invention is as follows: the gypsum tailing plastering material is characterized by being mainly formed by mixing raw materials of gypsum tailing powder, slag powder, an exciting agent, an early strength agent, redispersible latex powder and a water-retaining agent, wherein the gypsum tailing powder and the slag powder account for the following raw materials in percentage by mass: 50-70 parts of gypsum tailing powder and 30-50 parts of slag powder; adding an excitant and an early strength agent, wherein the excitant accounts for 0.8-1.2% of the mass of the gypsum tailing powder and the slag powder, and the early strength agent accounts for 1.3-1.7% of the mass of the gypsum tailing powder and the slag powder; adding re-dispersible emulsion powder and water-retaining agent, wherein the re-dispersible emulsion powder accounts for 1-3% of the mass of the gypsum tailing powder and the slag powder, and the water-retaining agent accounts for 0.8-1.5% of the mass of the gypsum tailing powder and the slag powder; the gypsum tailing powder is fine powder obtained by crushing gypsum tailings until the particle size is smaller than 10mm and then grinding the crushed gypsum tailings until the particle size is 0.08mm and the screen allowance is 15 percent; the slag powder is prepared by drying and grinding water-quenched slag or phosphorus slag until the specific surface area is larger than that of the slag powder5000cm²Fine powder per gram.

The excitant is quicklime or slaked lime. The early strength agent is finely ground alum stone powder or alum powder. The redispersible latex powder is a vinyl acetate product. The water-retaining agent is hydroxypropyl methyl cellulose.

The preparation method of the gypsum tailing plastering material is characterized by comprising the following steps: 1) preparation of gypsum tailing powder: crushing the gypsum tailings until the particle size is less than 10mm, and then grinding the gypsum tailings until 15 percent of fine powder is screened by a 0.08mm square-hole sieve for later use; 2) preparation of slag powder: drying and grinding the water quenching slag or the phosphorous slag until the specific surface area is more than 5000cm²The/g is standby (only the lower limit needs to be controlled); 3) the weight percentage of each raw material is as follows: 50-70 parts of gypsum tailing powder and 30-50 parts of slag powder, wherein the gypsum tailing powder and the slag powder are selected; selecting an exciting agent and an early strength agent according to the mass of 0.8-1.2% of the exciting agent in the gypsum tailing powder and the slag powder and the mass of 1.3-1.7% of the early strength agent in the gypsum tailing powder and the slag powder; selecting the redispersible latex powder and the water-retaining agent according to the mass of 1-3% of the redispersible latex powder and 0.8-1.5% of the water-retaining agent; and (5) uniformly mixing by using a mixer to obtain a product (packaged for delivery).

When in use, the water accounting for 25 to 35 percent of the product quality is added and evenly mixed for use.

The technical route adopted by the invention is as follows: the gypsum tailings are directly ground without calcining, mixed with ground slag in a certain proportion, and added with a proper amount of redispersible latex powder and a water-retaining agent, and under the action of a composite excitant (an excitant and an early strength agent are added), the novel water-resistant building plastering material is prepared.

The process of hydration hardening of plastering materials is explained as follows: after the cementing material meets water, Al₂(SO₄)₃、Ca(OH)₂The rapid dissolution of the dihydrate gypsum, with Ca being present in the liquid phase²⁺、SO₄ ^2-And OH^-Partially microcrystalline in the solid phase, e.g. C₂S, CA also start to hydrate:

at the same time, the slag surface begins to dissolve. The trace amount of free soluble silicon-aluminum component in the slag vitreous body is firstly dissolved in the solution, and simultaneously, the surface of the vitreous body absorbs OH in the solution^-When the adsorption amount reaches a certain degree, Al-O, Si-O chains in the network structure of the vitreous body are opened, and as a result, the surface of the vitreous body gradually disintegrates and dissolves, and the following reactions occur:

the calcium aluminate hydrate initially forms C₃AH₆In the form of C in alkaline solution₄AH₁₃Reacting with gypsum in the solution to produce ettringite.

When the hydration continues, the vitreous body is dissolved layer by layer, the hydration products are gradually increased, and the ettringite grows in a radial manner by taking the slag vitreous body (including other particles) as the support. The formedettringite crystals are mutually crossed and overlapped to form a spatial net structure around the particles. Meanwhile, a large amount of calcium silicate hydrate is formed, and the calcium silicate hydrate is filled among crystal nets of the ettringite to play a role in bonding and connect the dispersed crystal nets into a whole. The calcium silicate hydrate and the ettringite are mutually interwoven and linked to form the early structure of the hardened body.

The final hardened cement product is calcium silicate hydrate gel and ettringite, and also a large amount of gypsum, anhydrite, quartz, feldspar and unhydrated glass beads. The CSH gel has the main effect on the formation of the strength of the cementing material, bonds the ettringite crystal structure net and fills the pores, and bonds the particles to form a dense and high-strength hardened body for the cementing material.

The invention can use a large amount of gypsum tailings, and has simple production process and low production cost. The prepared plastering material has moderate setting time, high strength and good water resistance, and can be widely used for the inner and outer wall surfaces of various industrial and civil engineering.

Drawings

FIG. 1 is a process flow diagram of the present invention.

Detailed Description

In order to better understand the present invention, the following examples are further provided to illustrate the present invention, but the present invention is not limited to the following examples.

Example 1:

as shown in fig. 1, the preparation method of the gypsum tailing plastering material comprises the following steps: 1) preparation of gypsum tailing powder: crushing the gypsum tailings until the particle size is less than 10mm, and then grinding the gypsum tailings until 15 percent of fine powder is screened by a 0.08mm square-hole sieve for later use;

2) preparation of slag powder: drying and grinding the water-quenched slag discharged by steel enterprises to specific surface area of 5001-²The/g is ready for use;

3) grinding 60 mass percent of gypsum tailing powder and 40 mass percent of ground slag powder; adding activator (quicklime) accounting for 1% of the mass of the gypsum tailing powder and the slag powder and early strength agent (calcined alunite and ground into powder) accounting for 1.5% of the mass of the gypsum tailing powder and the slag powder, adding redispersible latex powder (vinyl acetate) accounting for 2% of the mass of the gypsum tailing powder and the slag powder and water-retaining agent (hydroxypropyl methyl cellulose) accounting for 1.0% of the mass of the gypsum tailing powder and the slag powder, mixing uniformly by using a mixer, and packaging to leave the factory. When in use, the water accounting for 25 to 35 percent of the product quality is added and evenly mixed for use.

Example 2:

the preparation method of the gypsum tailing plastering material comprises the following steps: 1) preparation of gypsum tailing powder: crushing the gypsum tailings until the particle size is less than 10mm, and then grinding the gypsum tailings until 15 percent of fine powder is screened by a 0.08mm square-hole sieve for later use; 2) preparation of slag powder: drying and grinding the water quenching slag until the specific surface area is more than 5000cm²The/g is ready for use; 3) mixing 70 wt% of stone30 mass percent of finely ground slag powder, an excitant (quicklime) accounting for 0.8 percent of the mass of the gypsum tailing powder and the slag powder and an early strength agent (calcined alunite and ground into powder) accounting for 1.3 percent of the mass of the gypsum tailing powder and the slag powder are added, and re-dispersible latex powder (vinyl acetate) accounting for 1 percent of the mass of the gypsum tailing powder and the slag powder and a water-retaining agent (specifically hydroxypropyl methyl cellulose) accounting for 0.8 percent of the mass of the gypsum tailing powder and the slag powder are added, mixed uniformly by a mixer and packaged to leave a factory. When in use, the water accounting for 25 to 35 percent of the product quality is added and evenly mixed for use.

Example 3:

the preparation method of the gypsum tailing plastering material comprises the following steps: 1) preparation of gypsum tailing powder: crushing the gypsum tailings until the particle size is less than 10mm, and then grinding the gypsum tailings until 15 percent of fine powder is screened by a 0.08mm square-hole sieve for later use; 2) slag of minePreparation of powder: drying and grinding the phosphorus slag until the specific surface area is more than 5000cm²The/g is ready for use; 3) mixing 70 mass percent of gypsum tailing powder, 30 mass percent of ground slag powder, an excitant (slaked lime) accounting for 1.2 mass percent of the gypsum tailing powder and the slag powder, an early strength agent (alunite powder) accounting for 1.7 mass percent of the gypsum tailing powder and the slag powder, redispersible latex powder (vinyl acetate which is a commercially available product) accounting for 3 mass percent of the gypsum tailing powder and the slag powder and a water-retaining agent (specifically hydroxypropyl methyl cellulose) accounting for 1.5 mass percent of the gypsum tailing powder and the slag powder uniformly by using a mixer, and packaging to leave a factory. When in use, the water accounting for 25 to 35 percent ofthe product quality is added and evenly mixed for use.

The upper and lower limit values and interval values of the raw materials of the gypsum tailing powder, the slag powder, the exciting agent, the early strength agent, the redispersible latex powder and the water-retaining agent can all realize the invention, and the examples are not necessarily listed here.

Claims

1. The gypsum tailing plastering material is characterized by mainly comprising gypsum tailing powder, slag powder, an excitant, an early strength agent and a subdividable componentThe gypsum tailing powder and the slag powder are mixed by the following raw materials in percentage by mass: 50-70 parts of gypsum tailing powder and 30-50 parts of slag powder; adding an excitant and an early strength agent, wherein the excitant accounts for 0.8-1.2% of the mass of the gypsum tailing powder and the slag powder, and the early strength agent accounts for 1.3-1.7% of the mass of the gypsum tailing powder and the slag powder; adding re-dispersible emulsion powder and water-retaining agent, wherein the re-dispersible emulsion powder accounts for 1-3% of the mass of the gypsum tailing powder and the slag powder, and the water-retaining agent accounts for 0.8-1.5% of the mass of the gypsum tailing powder and the slag powder; the gypsum tailing powder is fine powder obtained by crushing gypsum tailings until the particle size is smaller than 10mm and then grinding the crushed gypsum tailings until the particle size is 0.08mm and the screen allowance is 15 percent; the slag powder is prepared by drying and grinding water-quenched slag or phosphorus slag until the specific surface area is more than 5000cm²Fine powder per gram.

2. The gypsum tailing plastering material of claim 1, wherein: the excitant is quicklime or slaked lime.

3. The gypsum tailing plastering material of claim 1, wherein: the early strength agent is finely ground alum stone powder or alum powder.

4. The gypsum tailing plastering material of claim 1, wherein: the redispersible latex powder is a vinyl acetate product.

5. The gypsum tailing plastering material of claim 1, wherein: the water-retaining agent is hydroxypropyl methyl cellulose.

6. A method of preparing a gypsum tailing plastering material as claimed in claim 1, which comprises the steps of: 1) preparation of gypsum tailing powder: crushing the gypsum tailings until the particle size is less than 10mm, and then grinding the gypsum tailings until 15 percent of fine powder is screened by a 0.08mm square-hole sieve for later use; 2) preparation of slag powder: drying and grinding the water quenching slag or the phosphorous slag until the specific surface area is more than 5000cm²The/g is ready for use; 3) the weight percentage of each raw material is as follows: 50-70 of gypsum tailing powder and slag30-50 of powder, selecting gypsum tailing powder and slag powder; selecting an exciting agent and an early strength agent according to the mass of 0.8-1.2% of the exciting agent in the gypsum tailing powder and the slag powder and the mass of 1.3-1.7% of the early strength agent in the gypsum tailing powder and the slag powder; selecting the redispersible latex powder and the water-retaining agent according to the mass of 1-3% of the redispersible latex powder and 0.8-1.5% of the water-retaining agent; and (5) uniformly mixing by using a mixer to obtain the product.