Process for producing a building hard gypsum binder

Abstract

The application discloses a production process of a building hard gypsum binder, and belongs to the technical field of binder production, and comprises the following steps: step S1, hard gypsum raw ore is crushed in a jaw crusher, then is coarsely ground in a ball mill to obtain hard gypsum coarse powder, then the hard gypsum coarse powder and monocyanoamine are added into deionized water to be stirred and mixed to obtain a slurry, the slurry is added into a wet grinding machine to be finely ground, and after drying and scattering, hard gypsum fine powder is obtained; step S2, the hard gypsum fine powder is transferred into a rotary kiln to be calcined, is scattered after being cooled to room temperature, and calcined modified hard gypsum is obtained, a composite activator, slag and Portland cement clinker are added into the calcined modified hard gypsum to be uniformly mixed, and a building hard gypsum binder is obtained; through fine grinding and calcination treatment, the hydration activity of the hard gypsum in the binder is improved, the prepared hard gypsum binder has the advantages of fast hydration speed, uniform hydration degree, high strength after hydration and hardening, and good volume stability.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of cementing material production, and particularly relates to a production process of hard gypsum cementing material for building. BACKGROUND

[0002] At present, hard gypsum is not only limited to be used in the cement industry as a setting regulator, a composite mineralizer and a reinforcing agent, but also is widely used in the building industry. Hard gypsum cementing material (also referred to as hard gypsum cement) is prepared by mixing hard gypsum treated in a certain way with active activators and auxiliary materials. Hard gypsum products have the characteristics of light weight, sound insulation, heat insulation and fire resistance, and have unique advantages in energy saving, environmental protection and ecological balance. Compared with the hard gypsum resource reserves in China, the utilization rate of hard gypsum is not high. The main reason is that although natural hard gypsum has potential hydration activity, the hydration activity is poor, which is manifested in poor solubility in water, slow hydration speed, poor setting ability, no early strength and little direct use in building cementing materials. Therefore, the hard gypsum needs to be treated to stimulate and improve the activity of the hard gypsum. Therefore, how to improve the activity of hard gypsum is a problem to be solved at present. SUMMARY

[0003] The application aims to provide a production process of hard gypsum cementing material for building to solve the problems in the background.

[0004] The object of the application can be achieved by the following technical scheme.

[0005] A production process of hard gypsum cementing material for building comprises the following steps.

[0006] Step S1, hard gypsum ore is crushed to 5-6 cm in a jaw crusher, and then is coarsely ground in a ball mill to obtain hard gypsum coarse powder with a particle size of 200-300 mesh. Then, the hard gypsum coarse powder and monocyanoamine are stirred and mixed in deionized water to obtain a slurry with a solid content of 45-50%. The slurry is finely ground in a wet grinding machine, and after drying and scattering, hard gypsum fine powder is obtained.

[0007] Step S2, the hard gypsum fine powder is transferred into a rotary kiln and calcined for 2-3 h. After cooling to room temperature, the hard gypsum fine powder is scattered to obtain calcined modified hard gypsum. The composite activator, slag and portland cement clinker are added to the calcined modified hard gypsum, and are uniformly mixed in a mixer at a rotating speed of 2000-3000 r / min to obtain hard gypsum cementing material for building.

[0008] Further, the mass ratio of the hard gypsum coarse powder and the monomethylamine is 100:0.3-0.5. The molecules of the monomethylamine can be adsorbed on the surface and micro-cracks of the hard gypsum coarse powder, so that the surface free energy of the hard gypsum coarse powder is reduced, the unsaturated charge is neutralized, the dispersity of the hard gypsum coarse powder is improved, the fine grinding time is reduced, and the activity of the hard gypsum fine powder is improved.

[0009] Further, the specific surface area of the hard gypsum fine powder is 450-500 m 2 / kg. The fineness of the hard gypsum is reduced by coarse grinding and wet fine grinding, the specific surface area of the hard gypsum is improved, the water interaction ability is stronger, and the hydration hardening activity of the hard gypsum fine powder is higher.

[0010] Further, the calcination temperature of the rotary kiln is 150-200 DEG C. The content of the hemihydrate gypsum in the calcined modified hard gypsum is improved, the slurry with higher calcium ion and sulfate ion concentration can be obtained in use, the hydration activity of the hemihydrate gypsum is high, the dissolution speed is fast, the nucleation and growth speed of the dihydrate gypsum crystal is increased, and the hydration activity of the calcined modified hard gypsum is improved.

[0011] Further, the mass ratio of the calcined modified hard gypsum, the composite activator, the slag and the portland cement clinker is 80-85:4-5:13-15:5.

[0012] Further, the composite activator is composed of calcined alum and sulfate according to 3:1-2. The composite activator composed of the calcined alum and the sulfate can achieve the best activation effect.

[0013] Further, the sulfate is one or more of sodium sulfate, potassium sulfate and aluminum sulfate.

[0014] Further, the specific surface area of the slag is 500-600 m 2 / kg. The slag with the specific surface area can further improve the hydration activity of the calcined modified hard gypsum, and the volume stability and water resistance of the hard gypsum cementing material are improved.

[0015] The beneficial effects of the present application are as follows:

[0016] The present application breaks, coarsely grinds and finely grinds the natural hard gypsum ore, and obtains the hard gypsum fine powder with appropriate specific surface area. In the wet fine grinding process, the monomethylamine is added to promote the dispersion of the hard gypsum coarse powder particles, and the activity of the hard gypsum is maximized. Then, the calcination treatment can reduce impurities and increase the content of the hemihydrate gypsum, and further improve the hydration activity of the calcined modified hard gypsum, so that the hard gypsum cementing material can be quickly hydrated in use.

[0017] The application mixes calcined modified anhydrite, composite activator, slag and Portland cement clinker according to a suitable mass ratio to obtain a building anhydrite binder with fast hydration speed and uniform hydration degree, and the anhydrite binder has higher strength, volume stability and water resistance after hydration and hardening. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the embodiments of the application. Obviously, the described embodiments are only a part of the embodiments of the application, but not all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the application.

[0019] Embodiment 1

[0020] A production process of a building anhydrite binder includes the following steps.

[0021] Step S1, add anhydrite raw ore into a jaw crusher to crush to 6 cm, then add into a ball mill to coarsely grind to obtain anhydrite coarse powder with a particle size of 200 mesh, then add the anhydrite coarse powder and monocyanoamine into deionized water according to a mass ratio of 100:0.3 to stir and mix to obtain a slurry with a solid content of 45%, then add the slurry into a wet grinding machine to finely grind, and after drying and scattering, obtain anhydrite fine powder with a specific surface area of 450 m 2 / kg;

[0022] Step S2, transfer the anhydrite fine powder into a rotary kiln with a temperature of 200 DEG C to calcine for 2 h, and after cooling to room temperature, scatter to obtain calcined modified anhydrite, and according to a mass ratio of 80:4:13:5 of the calcined modified anhydrite, composite activator, slag and Portland cement clinker, add the composite activator, slag and Portland cement clinker into the calcined modified anhydrite, wherein the composite activator is composed of calcined alum and potassium sulfate mixed according to a ratio of 3:1; the specific surface area of the slag is 500 m 2 / kg, and mix uniformly in a mixer with a rotating speed of 2000 r / min to obtain a building anhydrite binder.

[0023] Embodiment 2

[0024] A production process of a building anhydrite binder includes the following steps.

[0025] Step S1, add the hard gypsum raw ore into the jaw crusher to crush to 5.5 cm, then add into the ball mill to coarsely grind to obtain the hard gypsum coarse powder with 250 mesh, then add the hard gypsum coarse powder and monocyanoamine into the deionized water according to the mass ratio of 100:0.4 to stir and mix, to obtain the slurry with solid content of 48%, then add the slurry into the wet grinding machine to finely grind, after drying and scattering, the hard gypsum fine powder with specific surface area of 480 m 2 / kg is obtained;

[0026] Step S2, transfer the hard gypsum fine powder into the rotary kiln with temperature of 170℃ to calcine for 2.5h, after cooling to room temperature, scatter to obtain the calcined modified hard gypsum, add the composite activator, slag and Portland cement clinker into the calcined modified hard gypsum according to the mass ratio of 82:4.5:14:5, wherein the composite activator is composed of calcined alum and sodium sulfate according to 3:1.5, the specific surface area of the slag is 550 m 2 / kg, mix uniformly in the mixer with rotating speed of 2500r / min to obtain the hard gypsum cementing material for building.

[0027] Example 3

[0028] A production process of a hard gypsum cementing material for building, comprising the following steps:

[0029] Step S1, add the hard gypsum raw ore into the jaw crusher to crush to 5 cm, then add into the ball mill to coarsely grind to obtain the hard gypsum coarse powder with 300 mesh, then add the hard gypsum coarse powder and monocyanoamine into the deionized water according to the mass ratio of 100:0.5 to stir and mix, to obtain the slurry with solid content of 50%, then add the slurry into the wet grinding machine to finely grind, after drying and scattering, the hard gypsum fine powder with specific surface area of 500 m 2 / kg is obtained;

[0030] Step S2, transfer the hard gypsum fine powder into the rotary kiln with temperature of 150℃ to calcine for 3h, after cooling to room temperature, scatter to obtain the calcined modified hard gypsum, add the composite activator, slag and Portland cement clinker into the calcined modified hard gypsum according to the mass ratio of 85:5:15:5, wherein the composite activator is composed of calcined alum and aluminum sulfate according to 3:2, the specific surface area of the slag is 600 m 2 / kg, mix uniformly in the mixer with rotating speed of 3000r / min to obtain the hard gypsum cementing material for building.

[0031] Comparative Example 1

[0032] The comparative example is compared with example 2, and the hard gypsum coarse powder is not finely ground, and the 250 mesh hard gypsum coarse powder is directly transferred into a rotary kiln for calcination treatment, and the subsequent raw materials and process steps are the same.

[0033] Comparative example 2

[0034] The comparative example is compared with example 2, and the hard gypsum coarse powder is not finely ground, and the 250 mesh hard gypsum coarse powder is directly transferred into a rotary kiln for calcination treatment, and the subsequent raw materials and process steps are the same.

[0035] Comparative example 3

[0036] The comparative example is compared with example 2, and only sodium sulfate is used as an activator, and the remaining raw materials and process steps are the same.

[0037] The hard gypsum binders prepared in examples 1-3 and comparative examples 1-3 are mixed with 30% of water by mass, and the standard consistency is reached, and then the hard gypsum binders are cured at room temperature and humidity of 60%, to obtain hard gypsum binder test pieces, and the performance of the hard gypsum binder test pieces is tested, and the results are shown in table 1:

[0038] Table 1

[0039]

[0040] As can be seen from the data in table 1, the hard gypsum binders prepared in examples 1-3 have a faster hydration and hardening speed and a smaller drying shrinkage than the comparative examples 1-3, and have a higher modulus of rupture and a higher compressive strength in terms of mechanical properties, and also have a higher softening coefficient, that is, have better water resistance, and thus the hard gypsum binders prepared in the present application have good comprehensive performance.

[0041] It should be noted that in this text, relational terms such as first and second are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between the entities or operations. Moreover, the terms "include", "contain" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed or inherent to such a process, method, article or device.

[0042] Although the embodiments of the present application have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to the embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A production process for anhydrous gypsum binder for building applications, characterized in that, Includes the following steps: Step S1: Add the raw anhydrite ore to a jaw crusher and crush it to 5-6 cm. Then, add it to a ball mill for coarse grinding to obtain anhydrite coarse powder of 200-300 mesh. Then, add the anhydrite coarse powder and cyanamide to deionized water at a mass ratio of 100:0.3-0.5 and stir to obtain a slurry with a solid content of 45-50%. Add the slurry to a wet grinding mill for fine grinding. After drying and dispersing, a specific surface area of ​​450-500 m² is obtained. 2 / kg of anhydrite powder; Step S2: Transfer the fine powder of anhydrite into a rotary kiln and calcine it at 150-200℃ for 2-3 hours. After cooling to room temperature, break it up to obtain calcined modified anhydrite. According to the mass ratio of calcined modified anhydrite, composite activator, slag and silicate cement clinker of 80-85:4-5:13-15:5, add composite activator, slag and silicate cement clinker to the calcined modified anhydrite and mix them evenly in a mixer with a speed of 2000-3000r / min to obtain anhydrite binder for building. The composite activator is composed of calcined alum and sulfate mixed in a ratio of 3:1-2; the slag has a specific surface area of ​​500-600 m². 2 / kg.

2. The production process of an anhydrite binder for building applications according to claim 1, characterized in that, The sulfate is one or more of sodium sulfate, potassium sulfate, and aluminum sulfate, or any mixture thereof.

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