CN114560670A - Filling material doped with red mud, desulfurized gypsum and slag and preparation method thereof - Google Patents

Abstract

A filling material doped with red mud, desulfurized gypsum and slag and a preparation method thereof belong to the technical field of filling materials. The filling material comprises red mud, slag and desulfurized gypsum, the bone cement ratio is 3-5, the mass concentration is 80% -84%, water is poured into the material to obtain filling slurry, the slag is excited by compounding the solid waste red mud and the desulfurized gypsum, and the coal gangue is used as the aggregate to prepare the paste filling material, so that the recovery rate of mineral resources can be improved, the land use value of a mining area can be recovered, meanwhile, a large amount of solid waste is utilized, the pollution to the environment is reduced, and good economic and environmental benefits are generated.

Description

A filling material mixed with red mud, desulfurized gypsum and slag and preparation method thereof

technical field

The invention relates to the technical field of filling materials, in particular to a filling material mixed with red mud, desulfurized gypsum and slag and a preparation method thereof.

Background technique

Mining will produce a wide range of goafs. The existence of goafs will cause surface subsidence, damage to infrastructure such as houses in the mining area, and affect the normal production and life of the mining area. In the process of industrial production such as coal mining and aluminum smelting A large number of solid wastes such as red mud, desulfurized gypsum, and coal gangue will be produced. These solid wastes are piled up on the surface in large quantities, not only occupying a large amount of land resources, but also through infiltration, sulfides, heavy metal ions and other pollutants will enter the groundwater, providing ecological Environmental safety poses a serious threat. The use of solid waste to prepare paste filling materials can not only effectively solve the problem of land resource waste and environmental pollution caused by the large amount of solid waste, but also effectively solve the problem of surface subsidence caused by goafs. For the purpose of sustainable development, the present invention utilizes solid waste red mud and desulfurized gypsum to compound excitation slag, and uses coal gangue as aggregate to prepare paste filling material, which can improve the recovery rate of mineral resources on the basis of controlling surface subsidence, restore The land use value of the mining area, while a large amount of solid waste is used, the pollution to the environment is reduced, and good economic and environmental benefits are produced.

The red mud used in the present invention is Bayer process red mud, which contains a large amount of incompletely reacted caustic soda, is strong in alkalinity and is difficult to utilize, and is often used in metal recovery, soil remediation, building materials, water treatment and waste gas treatment. Desulfurized gypsum is discharged from power plants. The bulk solid waste collected from the sulfur-containing tail gas by lime water, the main component is CaSO4 2H2O, is widely used in building materials and other industries. It produces sulfur, arsenic, mercury and fluoride, which pollutes the air and water resources. Its comprehensive utilization rate is only 53.7%. It was found through previous research and experiments that red mud and desulfurized gypsum were used to stimulate the slag, and coal gangue was used as the aggregate. The prepared filling body has good performance and can better meet the strength and fluidity requirements of filling.

In paste filling materials, cement is often used as a cementing material, but the cost of using cement as cementing material is high and a large amount of carbon emissions are generated in the cement production process. In recent years, alkali-excited slag is used as cementing material to prepare paste The bulk filling material has achieved good results, but the strong alkali activators NaOH and KOH with better excitation effect are expensive, and the sulfate contained in desulfurization gypsum has a better effect on slag in the alkaline environment provided by red mud. The cost of using it as an activator is much lower than that of using a traditional alkali activator, which can achieve the dual purpose of saving costs and disposing of solid waste. During preparation, only several materials need to be mixed with water. The preparation is simple and suitable for Strong sex.

SUMMARY OF THE INVENTION

Purpose of the invention: In view of the deficiencies in the prior art, the purpose of the present invention is to provide a filling material mixed with red mud, desulfurized gypsum and slag and a preparation method thereof. The present invention is the green utilization of solid waste and solves the problem of solid waste heap problems of ground subsidence in the goaf and goaf.

Technical solution: The present invention needs to dry and grind the red mud.

A filling material mixed with red mud, desulfurized gypsum and slag and a preparation method thereof, comprising the following steps:

(1) Weigh the corresponding mass of the materials required for production, and fix the total mass of the cementitious material composed of red mud, slag and desulfurized gypsum, the proportion of cementitious material and coal gangue aggregate, and the coarse and fine gangue in the aggregate. The mass ratio is unchanged, changing the red mud/slag, desulfurization gypsum/slag, and analyzing the combined excitation effect of red mud and desulfurization gypsum on slag;

(2) The design ranges of red mud/slag and desulfurization gypsum/slag are all 0.5 to 1;

(3) The ratio of water to the overall mass of the filling body, that is, the mass concentration is designed to be 80% to 84%;

(4) Coal gangue is used as aggregate, and the ratio of coal gangue to cementitious material is 3:1 to 5:1;

(5) The ratio of fine waste to coarse waste is 1:1 to 3:1.

Further, the red mud is put into a drying box to be dried at a temperature of 105±5° C. for 3 hours, and then put into a ball mill for grinding for 30 to 35 minutes and taken out.

Further, the red mud is stirred and mixed with slag and desulfurized gypsum, and water is added to prepare a cementitious material.

Further, the aggregate is black undisturbed coal gangue after crushing and screening.

Further, the fine aggregate is coal gangue sand with a particle size of less than 4.75mm, namely fine gangue, and the other aggregates with a particle size range of 4.75-13.2mm are coarse aggregate, ie coarse gangue.

Further, the black raw coal gangue is crushed and screened, the fine aggregate is coal gangue sand with a particle size of less than 4.75mm, that is, fine gangue, and the other aggregates with a particle size ranging from 4.75 to 13.2 mm are coarse aggregate, that is, coarse gangue.

Further, the coal gangue is added into the prepared cementitious material for full stirring, so that various materials of the filling body are fully mixed, and then put into a mold, and the air bubbles in the filling body are removed by vibration on a vibrating table.

Further, the filling body that has been cured in the curing box for 12 hours is subjected to mold removal treatment, cured to a specified age under standard conditions, and its uniaxial compressive strength is tested.

Beneficial effects: The specific surface area of the dried and ground red mud is significantly reduced, the excitation effect is significantly improved, and the strength is also significantly improved, and the strength of the filling body mixed with red mud is significantly improved at each age. The caustic soda material provides a good alkaline environment for the material reaction in the filling body, and the strength of the prepared filling body meets the filling requirements. The invention of this material will effectively solve the demand for new filling materials in paste filling and mining, and the research and application of the project can be more Good guidance on the practice of paste filling mining can improve the recovery rate of mineral resources on the basis of controlling the surface subsidence, restore the land use value of the mining area, and protect the residential housing in the mining area, which has significant economic benefits; at the same time, it uses a large amount of solid waste to reduce The pollution to the environment has been avoided, and good environmental benefits have been produced; after the implementation of the research results of the project, the geological disaster of mining subsidence in the mining area can be completely eliminated, which has important social benefits.

Description of drawings

Figure 1 is a graph showing the particle size distribution of red mud, slag and desulfurized gypsum.

Figure 2 is a broken line graph of the uniaxial compressive strength of the backfill of red mud and desulfurized gypsum composite excited slag at each age.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

The composite cemented filling material of the invention is prepared by mixing red mud, slag, desulfurized gypsum and coal gangue according to mass percentage, and the preparation method is to firstly mix the cementitious material composed of red mud, slag and desulfurized gypsum before adding water. Stir well before adding water and mixing with the cementitious material, and then add the coal gangue into the stirred cementitious material, so that the cementitious material and the aggregate are fully mixed to obtain a filling slurry.

Drying and grinding: put the agglomerated red mud in a drying box to dry, and then use a ball mill to grind for 30 minutes, and grind to 0.1-1000μm.

Crushing and screening: The black raw coal gangue is crushed and sieved. The fine aggregate is coal gangue sand with a particle size of less than 4.75mm, that is, fine gangue, and the remaining aggregates with a particle size ranging from 4.75 to 13.2 mm are coarse aggregate, that is, coarse gangue. .

Table 1 Filler proportions.

group red mud slag Desulfurized gypsum fine dust coarse waste Concentration 1 5 10 5 30 30 82% 2 4 8 8 30 30 82% 3 8 8 4 30 30 82%

Example 1:

The present embodiment provides a filling body mixed with red mud, slag and desulfurized gypsum. The mass concentration is 82%.

Example 2:

This embodiment provides a filling body mixed with red mud, slag and desulfurized gypsum, and the specific proportion is four parts of red mud, eight parts of slag, eight parts of desulfurized gypsum, thirty parts of fine gangue, and 30 parts of coarse gangue, The mass concentration is 82%.

Example 3:

The present embodiment provides a filling body mixed with red mud, slag and desulfurized gypsum, and the specific proportion is eight parts of red mud, eight parts of slag, four parts of desulfurized gypsum, thirty parts of fine gangue, and 30 parts of coarse gangue, The mass concentration is 82%.

Beneficial effects:

The main component of desulfurized gypsum is calcium sulfate, and sulfate can stimulate the slag.

Red mud contains a large amount of unreacted caustic alkali, which can better stimulate the slag and provide an alkaline environment for the material reaction in the filling body.

The higher the fineness of the red mud, the better the reaction of the cementitious material and the higher the strength of the filling.

Analysis of the formation mechanism of the strength of the filling body:

Slag is the main source of the strength of the backfill, but its activity is difficult to stimulate when used alone. Red mud provides an alkaline environment, and desulfurized gypsum provides sulfate.

The caustic alkali contained in red mud is the main reason for the formation of the alkaline reaction environment of the filling body, and red mud contains a large amount of aluminum ions, which is an important source for the formation of hydrated calcium aluminosilicate. It is used for skeleton support and filling and filling pores.

The main component of desulfurized gypsum is calcium sulfate, which can provide sulfate as an activator for slag, and desulfurized gypsum has good hydraulic and fluidity, which plays an important role in the early formation of the backfill body. The calcium it contains cooperates with the slag to provide calcium. The resulting products such as hydrated calcium silicate, hydrated calcium aluminosilicate, and ettringite fill the inter-aggregate pores, so that the internal structure of the filling body is more compact and the filling body forms strength.

The filling body material prepared by the invention can meet the requirements of strength and fluidity in the filling construction of mines, and can maintain safe production of the mine and eliminate the harm caused by the goaf.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (5)

1. The filling material doped with the red mud, the desulfurized gypsum and the slag and the preparation method thereof are characterized by comprising the following steps:

(1) putting the agglomerated undisturbed red mud into a drying box for drying, and then grinding the red mud to the particle size of 0.1-1000 mu m by using a ball mill for later use;

(2) crushing black original-state coal gangue, screening, collecting coal gangue particles with the particle size range of 0-13.2 mm after crushing, taking coal gangue sand with the particle size of less than 4.75mm as fine aggregate, and taking the rest coal gangue with the particle size range of 4.75-13.2 mm as coarse aggregate for later use;

(3) uniformly mixing the red mud, the desulfurized gypsum and the S95-grade slag in the step (1), adding water, and stirring for 3-5 min to obtain a cementing material, wherein the cementing material is prepared from the following components in percentage by weight: 0.5-1 of red mud/slag and 0.5-1 of desulfurized gypsum/slag;

(4) adding the coal gangue aggregate in the step (2) into the cementing material prepared in the step (3), and uniformly stirring for 5-7 min to obtain the filling material, wherein the coal gangue and the cementing material powder are prepared according to the mass ratio: 3-5, wherein the mass ratio of the fine aggregate to the coarse aggregate is 1-3.

2. The filling material doped with red mud, desulfurized gypsum and slag and the preparation method thereof according to claim 1, wherein: the red mud is placed into a drying box to be dried for 3 hours at the temperature of 105 +/-5 ℃, then the red mud is placed into a ball mill to be ground for 30-35 min and then the ground red mud is taken out.

3. The filling material doped with red mud, desulfurized gypsum and slag and the preparation method thereof according to claim 1, wherein: the gelled material and the filling body slurry are stirred by a JJ-5 type mortar stirrer, the gelled material is stirred quickly, and the filling body slurry is stirred slowly.

4. The filling material doped with red mud, desulfurized gypsum and slag and the preparation method thereof according to claim 1, wherein: and (3) airing the black undisturbed coal gangue in the step (2) to enable the water content of the black undisturbed coal gangue to be lower than 10%.

5. The filling material doped with red mud, desulfurized gypsum and slag and the preparation method thereof according to claim 1, wherein: the variation range of the mass concentration in the step (4) is as follows: 80-84%.

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