Mine filling cementitious material, preparation method and application thereof

Abstract

The application discloses a mine filling cementing material and a preparation method and application thereof, and comprises the following raw materials in mass fraction: 62-72 parts of red mud; 5-15 parts of carbide slag; 8-18 parts of desulfurization gypsum; 2-8 parts of bentonite; and 2-8 parts of bauxite. The application utilizes the mutual reaction among the red mud, the carbide slag and the desulfurization gypsum, so as to form a large amount of hydration products such as ettringite, C-S-H gel and calcium melilite. When filled into the mine, the hydration products can be well solidified and have a relatively high compressive strength, and the compressive strength is all more than 1.5 MPa, so that the requirements of the existing norms on the mine filling material are met. In addition, the raw materials in the application are basically the recycling of solid waste, have low cost, are environment-friendly, and can realize large-scale waste recycling, so that the mine filling cementing material in the application can be completely used as a green alternative scheme for filling in the goaf in the prior art.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of resource recycling, and particularly relates to a mine filling cementing material and a preparation method and application thereof. BACKGROUND

[0002] Red mud is a waste product of alumina production, and 1.0-1.6 tons of red mud is discharged for each ton of alumina produced. With the rapid development of China's national economy, about 8 million tons of red mud is discharged annually, and a large amount of red mud can only be piled up because it cannot be effectively utilized. Piling up of red mud causes many environmental problems such as land occupation, air pollution, surface water pollution, and groundwater resource pollution. Therefore, treatment and comprehensive utilization of red mud has attracted great attention and attention. According to different alumina production processes, red mud can be divided into sintered red mud, Bayer red mud and combined red mud. The Bayer red mud does not contain water-hardening active minerals and has poor permeability because it is not calcined at high temperature and has fine particles, and is difficult to drain and dewater, and is usually in a flow plastic-soft plastic state. It is the most difficult to be resourcefully utilized among the three types of red mud, and is difficult to be piled up. For a long time, scholars at home and abroad have carried out a lot of research on the comprehensive utilization of Bayer red mud, and although many effective schemes have been put forward, most of them are either technically feasible but economically unreasonable, or laboratory feasible but difficult to control in practical application. The comprehensive utilization of Bayer red mud cannot achieve good economic benefits, and cannot substantially solve the problem of increasing storage of Bayer red mud which is urgently needed to be treated in the aluminum industry. In recent years, due to the decrease in the price of alumina, alumina plants in China have gradually abandoned the sintering method and the combined method which have high alumina production costs, and the Bayer method has become the main method for alumina production in China, resulting in an increasing amount of Bayer red mud. Therefore, the bulk utilization of Bayer red mud is imminent. Guangxi Pingguo Aluminum Company has overcome the technology of red mud iron separation, and further recovers iron from red mud in alumina production, but it is limited to this, and the red mud after iron separation is still piled up and cannot be further utilized. SUMMARY

[0003] In order to overcome the problems existing in the prior art, one of the purposes of the present application is to provide a mine filling cementing material.

[0004] The second purpose of the present application is to provide a preparation method of the mine filling cementing material.

[0005] The third purpose of the present application is to provide a mine filling cementing material.

[0006] The fourth purpose of the present application is to provide an application of the mine filling cementing material in mine filling materials or building materials.

[0007] In order to achieve the above purposes, the technical scheme adopted by the present application is:

[0008] The first aspect of the present application is to provide a mine filling cementing material, which comprises the following raw materials in mass fraction: 62-72 parts of red mud; 5-15 parts of carbide slag, 8-18 parts of desulfurization gypsum; 2-8 parts of bentonite; 2-8 parts of bauxite.

[0009] The invention idea of the mine filling cementing material in the present application is as follows: the red mud used in the present application has a low content of silicon oxide, and the amount of C-S-H gel generated by the hydration reaction of the red mud with other activators is limited, which cannot meet the requirement of becoming a cementing material. However, the content of aluminum oxide in the red mud is high, so it is necessary to utilize the aluminum oxide in the red mud, and the aluminum oxide must be used as the main source of the activity of the red mud. The effective way to activate the aluminum oxide is to make it react to generate hydraulic calcium aluminate. The main component of the carbide slag is Ca(OH)2, which does not have hydraulicity. The main component of the desulfurization gypsum is calcium sulfate dihydrate (CaSO4·2H2O), which also does not have hydraulicity. When the carbide slag is added to the red mud, on the one hand, the Ca 2+ reacts with the dissolved Al in the red mud to generate calcium aluminate, and reacts with the dissolved Si in the red mud to generate C-S-H gel, which reduces the concentrations of Al, Si and SO4 2- in the solution; on the other hand, the concentration of OH - in the solution increases. Under the action of the two aspects, the red mud is further dissolved, and the concentration of Na ions increases, which indicates that the carbide slag has an activating effect on the red mud, and the activating effect of the carbide slag is manifested as “calcium supplementing and alkali increasing”. The main component of the desulfurization gypsum is calcium sulfate dihydrate (CaSO4·2H2O), which also does not have hydraulicity. After the desulfurization gypsum is added to the red mud-carbide slag solution, due to the dissolution of the desulfurization gypsum, the concentrations of Ca 2+ and SO4 2- significantly increase, the hydration reaction slowly proceeds, the hydration products such as calcium aluminate and C-S-H gel gradually grow, the coating film on the surface of the red mud gradually cracks, the red mud rapidly dissolves, a large amount of hydration products such as calcium aluminate, C-S-H gel and calcium melinite are generated, and the consumption of Ca 2+ is accelerated, which further promotes the rapid dissolution of the carbide slag and the desulfurization gypsum, thereby obtaining the mine filling cementing material in the present application. A large amount of calcium aluminate is generated in the hydration reaction in the red mud-carbide slag-desulfurization gypsum system. As can be seen from the molecular formula of calcium aluminate (3CaO·Al2O3·3CaSO4·32H2O), in order to make Al2O3 hydrate to generate calcium aluminate, in addition to CaSO4, CaO is also required. Therefore, in the red mud system which belongs to a strong alkali, the “calcium supplementing” effect of the carbide slag is much greater than the “alkali increasing” effect, which not only provides the required Ca 2+ for the generation of C-S-H gel and calcium melinite, but also provides the required Ca 2+Desulfurization gypsum mainly promotes the activity of red mud, and its role is as follows: (1) reacts with Al and Ca 2+ , OH - , SO4 2- dissolved in red mud to generate hydraulic ettringite, the generation of ettringite reduces the concentration of Al in the solution, promotes the further dissolution of red mud, and the continuous generation of ettringite enables the effective activation of Al2O3 in red mud; (2) the ettringite crystal forms a net structure of the wrapping layer on the surface of the red mud particles, and the tightness is small, which is beneficial to ion diffusion and enables the continuous hydration of red mud; (3) SO4 2- can replace part of SO4 4- in C-S-H gel, and the replaced SO4 4- is free, and the solubility of Al will obviously increase in the presence of SO4 4- , which is beneficial to promote the further hydration of red mud.

[0010] According to the above analysis, for the present application, red mud is the main structural material, and the proportion thereof must be more than 60%, so that a large amount of Al2O3 can be activated into ettringite, and the amount of red mud selected in the present application is 62-72%. Calcium carbonate in the process of generating ettringite and C-S-H gel plays a role of calcium supplement, and according to the content of the raw material, the content of calcium carbonate in the present application needs to be between 5-15%, and less than 5% will cause the amount of Ca 2+ ion to be insufficient in the process of generating ettringite, and the final strength cannot meet the requirements; and higher than 15% will cause the alkalinity to be too high in the hydration process, and inhibit the occurrence of the hydration reaction. Desulfurization gypsum plays a role of alkali activation in the present application, increases the concentration of Ca 2+ and SO4 2- , breaks the ettringite and C-S-H gel coating film generated in the early stage, and red mud is rapidly dissolved, so that a large amount of hydration products such as ettringite, C-S-H gel and calcium nepheline are generated, and therefore the amount of desulfurization gypsum in the present application is slightly higher than that of calcium carbonate, and is 8-18%. Finally, in order to balance the amount of Al and Ca in the cementitious material, 2-8 parts by mass of bentonite and 2-8 parts by mass of bauxite are added, so that the hydration reaction proceeds in the optimal direction.

[0011] Preferably, the red mud is low-iron red mud; and the low-iron red mud is red mud after extraction of iron elements.

[0012] Preferably, the red mud comprises the following components in mass percentage: SiO2 18-21%, Al2O3 20-23%, Fe2O3 11-14%, CaO 15-18%, Na2O 5-8%, loss on ignition 22-25%; further preferably, the red mud comprises the following components in mass percentage: SiO2 19-20%, Al2O3 21-22%, Fe2O3 12-13%, CaO 16-17%, Na2O 6-7%, loss on ignition 23-24%; still further preferably, the red mud comprises the following components in mass percentage: SiO2 19.43%, Al2O3 21.30%, Fe2O3 12.28%, CaO 16.92%, Na2O 6.43%, loss on ignition 23.64%.

[0013] Preferably, the specific surface area of the red mud is 900-1000 m2 / g. 2 · kg -1 .

[0014] Preferably, the water content in the red mud is < 1%.

[0015] Preferably, the content of the red mud is 65-67 parts.

[0016] Preferably, the specific surface area of the desulfurization gypsum and / or carbide slag is 1200-1500 m2 / g. 2 · kg -1 .

[0017] Preferably, the water content in the desulfurization gypsum and / or carbide slag is < 1%.

[0018] Preferably, the content of the desulfurization gypsum is 13-18 parts.

[0019] Preferably, the desulfurization gypsum comprises the following components in mass percentage: SiO2 1-4%, Al2O3 0.8-1.2%, CaO 32-35%, Na2O 0.3-0.6%, SO3 41-44%, loss on ignition 19-22%; further preferably, the desulfurization gypsum comprises the following components in mass percentage: SiO2 2-3%, Al2O3 0.9-1.1%, CaO 33-34%, Na2O 0.4-0.5%, SO3 42-43%, loss on ignition 20-21%; still further preferably, the desulfurization gypsum comprises the following components in mass percentage: SiO2 2.33%, Al2O3 1.08%, CaO 33.57%, Na2O 0.46%, SO3 42.50%, loss on ignition 20.06%.

[0020] Preferably, the content of the carbide slag is 8-10 parts.

[0021] Preferably, the carbide slag comprises the following components in mass percentage: SiO2 2-5%, Al2O3 1-4%, CaO 61-64%, Na2O 0.8-1.1%, Fe2O3 0.5-0.8%, and loss on ignition 29-32%; further preferably, the carbide slag comprises the following components in mass percentage: SiO2 3-4%, Al2O3 2-3%, CaO 62-63%, Na2O 0.9-1%, Fe2O3 0.6-0.7%, and loss on ignition 30-31%; still further preferably, the carbide slag comprises the following components in mass percentage: SiO2 3.65%, Al2O3 2.0%, CaO 62.34%, Na2O 0.98%, Fe2O3 0.65%, and loss on ignition 30.38%.

[0022] Preferably, the content of the bentonite is 4-5 parts.

[0023] Preferably, the bentonite comprises the following components in mass percentage: SiO2 68.51-71.37%, Al2O3 14.58-15.85%, Na2O 3.61-4.18%, Fe2O3 3.29-3.91%, CaO 1.93-2.68%, MgO 1.92-2.16%, K2O 1.00-1.24%, TiO2 0.50-0.67%, and other oxides less than 2%.

[0024] Preferably, the bentonite has a particle size of 1-100 um, a D50 of 13.17 um, and a D90 of 32.8 um.

[0025] Preferably, the bauxite has a particle size of 200 mesh.

[0026] Preferably, the bauxite comprises the following components in mass percentage: Al2O3 content greater than 85%, Fe2O3 content less than 2.0%, and TiO2 content less than 4%.

[0027] Preferably, the bauxite has a density of 3.1-3.5 g / cm 3 .

[0028] Preferably, the content of the bauxite is 4-6 parts.

[0029] The second aspect of the present application provides a preparation method of the mine filling cementing material provided in the first aspect of the present application, which comprises the following steps: mixing and ball-milling red mud, carbide slag, desulfurization gypsum, bentonite and bauxite according to mass ratio to prepare the mine filling cementing material.

[0030] Preferably, the mixing ball milling step is specifically ball milling at a speed of 250-350 r / min for 15-25 min; more preferably, the mixing ball milling step is specifically ball milling at a speed of 280-320 r / min for 18-22 min; even more preferably, the mixing ball milling step is specifically ball milling at a speed of 300 r / min for 10 min in the forward direction and then for 10 min in the reverse direction.

[0031] Preferably, the red mud, carbide slag and desulfurization gypsum need to be dried before use and then ball milled.

[0032] Preferably, the drying step is specifically drying the red mud, carbide slag and desulfurization gypsum to a water content of ≤1%.

[0033] Preferably, the ball milling step of the red mud, carbide slag and desulfurization gypsum is specifically ball milling the red mud, carbide slag and desulfurization gypsum to a required specific surface area.

[0034] Preferably, the ball milling of the red mud, carbide slag and desulfurization gypsum is performed using a ball mill, and the rotational speed of the ball mill is 900-1100 r / min.

[0035] The third aspect of the present application provides a mine filling cementing material, which comprises the mine filling cementing material provided by the first aspect of the present application and classified tailings; and the mass ratio of the mine filling cementing material to the classified tailings is 1:(6-10).

[0036] Preferably, the mass ratio of the mine filling cementing material to the classified tailings is 1:(7-9).

[0037] Preferably, the mine filling cementing material further comprises water.

[0038] Preferably, the solid content in the mine filling cementing material is 60-70%; more preferably, the solid content in the mine filling cementing material is 64-66%.

[0039] Preferably, the parameters of the classified tailings are as follows: specific gravity is 3-3.5, loose dry bulk density is 1.5 t / m 3 ~1.8 t / m 3 , compact dry bulk density is 2 t / m 3 ~2.3 t / m 3 , maximum porosity is 45%-50%, minimum porosity is 35%-40%, and natural repose angle is 35°-40°.

[0040] Preferably, the particle size parameters of the classified tailings are as follows: 4wt% to 5wt% of 5μm or less (0μm to 5μm, excluding 5μm), 3wt% to 4wt% of 5μm to 10μm, 9.5wt% to 10.5wt% of 10μm to 20μm, 23.5wt% to 24.5wt% of 20μm to 50μm, 16wt% to 17wt% of 50μm to 80μm, 8wt% to 9wt% of 80μm to 100μm, 22wt% to 23wt% of 100μm to 200μm, 9.5wt% to 10.5wt% of 200μm to 400μm, and 0.2wt% to 0.5wt% of 400μm to 502μm; further preferably, the particle size parameters of the classified tailings are as follows: 4.19wt% of 5μm or less, 3.89wt% of 5μm to 10μm, 9.9wt% of 10μm to 20μm, 24.05wt% of 20μm to 50μm, 16.43wt% of 50μm to 80μm, 8.77wt% of 80μm to 100μm, 22.52wt% of 100μm to 200μm, 9.92wt% of 200μm to 400μm, and 0.33wt% of 400μm to 502μm.

[0041] Preferably, the classified tailings comprise the following components in mass percentage: 30% to 31% of SiO2, 7% to 8% of Al2O3, 5.5% to 6.5% of MgO, 5% to 6% of SO3, 0.05% to 0.1% of P2O5, 5% to 6% of Fe2O3, 18% to 19% of CaO, 0.3% to 0.7% of TiO2, 0.1% to 0.2% of BaO, and 0.8% to 1.2% of PbO; further preferably, the classified tailings comprise the following components in mass percentage: 30.315wt% of SiO2, 7.564wt% of Al2O3, 6.018wt% of MgO, 5.350wt% of SO3, 0.07wt% of P2O5, 5.303wt% of Fe2O3, 18.482wt% of CaO, 0.507wt% of TiO2, 0.183wt% of BaO, and 1.003wt% of PbO.

[0042] Preferably, the classified tailings are classified tailings of lead-zinc mine.

[0043] The fourth aspect of the present application provides the use of the mine filling cementitious material provided by the first aspect of the present application in mine filling material or building material.

[0044] Preferably, when used as mine filling material, the mine filling cementitious material can be delivered to the site to be filled by pipeline.

[0045] The beneficial effects of the present application are: the present application utilizes the mutual reaction among red mud, carbide slag and desulfurization gypsum, thereby forming a large amount of ettringite, C-S-H gel, calcium melilite and other hydration products, which can be well solidified and have high compressive strength when filled into the mine, and the compressive strength is all more than 1.5 MPa, meeting the requirements of the existing specification on mine filling materials. In addition, the raw materials in the present application are basically the recycling of solid waste, which is low in cost, friendly to the environment, and can realize large-scale waste recycling, so the mine filling cementing material in the present application can be completely used as a green alternative scheme for filling in the goaf of the existing technology. DETAILED DESCRIPTION

[0046] The specific implementation of the present application is further described in detail below in combination with examples, but the implementation and protection of the present application are not limited thereto. It should be noted that if the following processes are not specifically described in detail, they can be implemented or understood by referring to the existing technology by those skilled in the art. If the reagents or instruments used are not marked with the manufacturer, they are considered to be conventional products that can be purchased on the market.

[0047] The information of the raw materials used in the examples and comparative examples of the present application is as follows:

[0048] The Pingguo aluminum low-iron red mud is the red mud after iron removal and stacking of Pingguo Aluminum Industry Company, and its chemical composition is as follows: SiO2 accounts for 19.43%, Al2O3 accounts for 21.30%, Fe2O3 accounts for 12.28%, CaO accounts for 16.92%, Na2O accounts for 6.43%, and the loss on ignition is 23.64%.

[0049] The carbide slag is a stacking waste material of a certain chemical company, and its chemical composition is as follows: SiO2 accounts for 3.65%, Al2O3 accounts for 2.0%, CaO accounts for 62.34%, Na2O accounts for 0.98%, Fe2O3 accounts for 0.65%, and the loss on ignition is 30.38%.

[0050] The desulfurization gypsum is an industrial grade raw material purchased on the market, and its chemical composition is as follows: SiO2 accounts for 2.33%, Al2O3 accounts for 1.08%, CaO accounts for 33.57%, Na2O accounts for 0.46%, SO3 accounts for 42.50%, and the loss on ignition is 20.06%.

[0051] Bentonite is a mature industrial grade raw material purchased in the market, and its chemical composition is as follows: SiO2 accounts for 68.51-71.37%, Al2O3 accounts for 14.58-15.85%, Na2O accounts for 3.61-4.18%, Fe2O3 accounts for 3.29-3.91%, CaO accounts for 1.93-2.68%, MgO accounts for 1.92-2.16%, K2O accounts for 1.00-1.24%, TiO2 accounts for 0.50-0.67%, and other oxides account for less than 2%, the particle size is concentrated between 1-100 um, D50 is 13.17 um, and D90 is 32.8 um.

[0052] The bauxite particle size is 200 mesh, the Al2O3 content is greater than 85%, the Fe2O3 content is less than 2.0%, the TiO2 content is less than 4%, and the density is 3.1-3.5 g / cm 3 .

[0053] The particle size distribution of the classified tailings is as follows: 4.19wt% below 5μm, 3.89wt% between 5μm and 10μm, 9.9wt% between 10μm and 20μm, 24.05wt% between 20μm and 50μm, 16.43wt% between 50μm and 80μm, 8.77wt% between 80μm and 100μm, 22.52wt% between 100μm and 200μm, 9.92% between 200μm and 400μm, and 0.33wt% between 400μm and 502μm. The classified tailings include the following components in mass percentage: 30.315wt% SiO2, 7.564wt% Al2O3, 6.018wt% MgO, 5.350wt% SO3, 0.07wt% P2O5, 5.303wt% Fe2O3, 18.482wt% CaO, 0.507wt% TiO2, 0.183wt% BaO, and 1.003wt% PbO. The specific gravity of the classified tailings is 3-3.5, the loose dry bulk density is 1.5t / m 3 -1.8t / m 3 , the compact dry bulk density is 2t / m 3 -2.3t / m 3 , the maximum porosity is 45%-50%, the minimum porosity is 35%-40%, and the natural repose angle is 35°-40°.

[0054] Example 1:

[0055] The compositions of the various preparation raw materials in the mine filling cementitious material in this example are shown in Table 1.

[0056] Table 1: Preparation raw material ratio of the mine filling cementitious material in this example

[0057] Raw materials Mass parts apple aluminum low-iron red mud 67 carbide slag 10 desulfurization gypsum 13 bentonite 4 bauxite 6

[0058] Example 2

[0059] The composition of each raw material for preparing the mine filling cementitious material in this example is shown in Table 2 below:

[0060] Table 2 Raw material ratio for preparing the mine filling cementitious material in this example

[0061]

[0062]

[0063] Example 3

[0064] The composition of each raw material for preparing the mine filling cementitious material in this example is shown in Table 3 below:

[0065] Table 3 Raw material ratio for preparing the mine filling cementitious material in this example

[0066] Raw materials Mass parts apple aluminum low-iron red mud 63 carbide slag 7 desulfurization gypsum 16 bentonite 8 bauxite 6

[0067] Example 4

[0068] The composition of each raw material for preparing the mine filling cementitious material in this example is shown in Table 4 below:

[0069] Table 4 Raw material ratio for preparing the mine filling cementitious material in this example

[0070] Raw materials Mass parts apple aluminum low-iron red mud 69 carbide slag 12 desulfurization gypsum 10 bentonite 3 bauxite 6

[0071] Example 5

[0072] The composition of each raw material for preparing the mine filling cementitious material in this example is shown in Table 5 below:

[0073] Table 5 Raw material ratio for preparing the mine filling cementitious material in this example

[0074] Raw materials Mass parts apple aluminum low-iron red mud 71 carbide slag 14 desulfurization gypsum 9 bentonite 3 bauxite 3

[0075] The mine filling cementitious material in Examples 1-5 of the present application is prepared by the following method, which specifically comprises the following steps:

[0076] 1) The Pingguo aluminum low-iron red mud is placed in a 50℃ oven and dried for 24h, and its water content is measured to ensure that the water content is less than or equal to 1%, then it is placed in a ball mill, and an appropriate amount of standard small grinding balls are added, then the ball mill is started at a speed of 1000r / min, and the specific surface area is measured to be 900-1000m 2 ·kg -1 , and then the Pingguo aluminum low-iron red mud powder is obtained for standby use;

[0077] 2) The carbide slag and desulfurization gypsum are respectively placed in an oven at 50°C, dried for 8h, and the water content is measured to ensure that the water content is less than or equal to 1%, and then they are placed in a ball mill, an appropriate amount of standard small grinding balls are added, and then the ball mill is started at a speed of 1000r / min, and the specific surface area is measured to make the surface area 1200-1500m 2 ·kg -1 Then the carbide slag and desulfurization gypsum powder are obtained for standby use.

[0078] 3) The red mud powder, carbide slag powder, desulfurization gypsum powder, bentonite and bauxite are added to the planetary ball mill at a speed of 300r / min for 20min (10min forward rotation and 10min reverse rotation), and the powders are mixed uniformly to obtain the mine filling cementing material in the present application.

[0079] Example 6:

[0080] The mine low-concentration filling cementing material in this example includes water, the mine filling cementing material in Example 1 and classified tailings; wherein the mass ratio of the mine filling cementing material and the classified tailings is 1:8; and the solid content in the mine low-concentration filling cementing material is 65%.

[0081] The preparation method of the mine low-concentration filling cementing material in this example is as follows:

[0082] 1) The mine filling cementing material in Example 1 and the classified tailings are added to the stirrer at a mass ratio of 1:8 and stirred for 10min to make them uniformly mixed.

[0083] 2) An appropriate amount of water is added, the slurry is prepared to a concentration with a solid content of 65%, and rapid stirring is performed for 10min to obtain the mine low-concentration filling cementing material in this example, which can be applied to mine filling. The mine low-concentration filling cementing material in this example has good fluidity and can be used for filling work in the mined-out area of the mine by pipeline.

[0084] Comparative Example 1:

[0085] The compositions of the various preparation raw materials in the mine filling cementing material in this example are shown in Table 6:

[0086] Table 6 Preparation raw material ratio of the mine filling cementing material in this example

[0087] Raw materials Mass parts apple aluminum low-iron red mud 80 carbide slag 15 desulfurization gypsum 0 bentonite 2 bauxite 3

[0088] Comparative Example 2:

[0089] The compositions of the various preparation raw materials in the mine filling cementing material in this example are shown in Table 7:

[0090] Table 7 Preparation raw material ratio of the mine filling cementing material in this example

[0091]

[0092] Comparative Example 3

[0093] The compositions of the preparation raw materials in the mine filling cementitious material in this example are shown in Table 8 below:

[0094] Table 8 Preparation raw material ratio of the mine filling cementitious material in this example

[0095] Raw materials Mass parts apple aluminum low-iron red mud 62 carbide slag 20 desulfurization gypsum 10 bentonite 3 bauxite 5

[0096] Comparative Example 4

[0097] The compositions of the preparation raw materials in the mine filling cementitious material in this example are shown in Table 9 below:

[0098] Table 9 Preparation raw material ratio of the mine filling cementitious material in this example

[0099] Raw materials Mass parts apple aluminum low-iron red mud 72 carbide slag 15 desulfurization gypsum 5 bentonite 3 bauxite Raw materials Mass parts apple aluminum low-iron red mud carbide slag desulfurization gypsum bentonite bauxite 5

[0100] Comparative Example 5

[0101] The compositions of the preparation raw materials in the mine filling cementitious material in this example are shown in Table 10 below:

[0102] Table 10 Preparation raw material ratio of the mine filling cementitious material in this example

[0103]

[0104]

[0105] The mine filling cementitious materials in Comparative Examples 1-5 were prepared according to the preparation methods described in Examples 1-5.

[0106] Performance test:

[0107] In order to test the compressive strength of the mine filling cementitious materials in Examples 1-5 and Comparative Examples 1-5, the following experiments were performed, and the specific experimental steps were as follows:

[0108] 1) The mine filling cementitious materials obtained in Examples 1-5 and Comparative Examples 1-5 were respectively added to a stirrer together with classified tailings and stirred and mixed for 10 min to make them uniformly mixed, wherein the mass ratio of the mine filling cementitious materials in Examples 1-5 and Comparative Examples 1-5 to the classified tailings was 1:8.

[0109] 2) Add water to the mixture of cementing material and classified tailings in the mine in step 1) to prepare slurries in Examples 1-5 and Comparative Examples 1-5 to have a solid content of 65%, and stir rapidly for 10 min, and scrape the slurries around the pot wall into the pot, and then stir for 30 s to obtain the mine filling cementing material slurries in Examples 1-5 and Comparative Examples 1-5, respectively.

[0110] 3) Pour the mine filling cementing material slurries prepared in step 2) into a standard triple test mold of 70.7*70.7*70.7 mm, and pour three groups of samples for each group of samples to obtain test blocks;

[0111] 4) Put the test blocks obtained in step 3) into a standard curing box with a temperature of 20°C and a relative humidity of 90%, and after curing for 7 days, remove the test blocks from the curing box and put them back into the curing box for curing until the corresponding age, and use a full-automatic pressure testing machine to measure the 28-day strength at a speed of 10 N / s, and test three test blocks for each age, and take the average value as the uniaxial compressive strength of the filling body at the age. The uniaxial compressive strength data of the mine filling cementing materials in Examples 1-5 and Comparative Examples 1-5 are recorded in Table 11.

[0112] Table 11 Uniaxial compressive strength performance data

[0113]

[0114]

[0115] As can be seen from Table 11, the 28d strength of Comparative Example 1 without desulfurized gypsum and Comparative Example 2 without adding carbide slag is only 0.31 MPa and 0.25 MPa, which is far lower than the strength of the mine filling cementing materials in Examples 1-5, indicating that the desulfurized gypsum and the carbide slag are the red mud activator and provide the necessary conditions for the formation of the strength of the mine filling cementing material. The content of the carbide slag in Comparative Example 3 is 20%, which exceeds the upper limit of the optional range of the amount used in the application (i.e. 15%), and the final strength is 1.14 MPa, which shows that the excessive use of the carbide slag will inhibit the overall strength. The amount of desulfurized gypsum in Comparative Example 4 is 5%, which is lower than the minimum value of 8 in the optional range of the amount used in the application, and the 28d strength is 1.27 MPa. The content of the red mud in Comparative Example 5 is 50%, which is less than the amount used in Examples 1-5, and the content of the carbide slag is 20%, which will further inhibit the hydration, and thus the 28d strength is only 0.91 MPa. Through the comparison of the strength performance of Comparative Examples 1-5 and Examples 1-5, it can be seen that the red mud, desulfurized gypsum, carbide slag and other components in the application have a synergistic effect, and the excessive use or insufficient amount of any component will adversely affect the overall performance of the material, reduce the strength of the material, and cannot meet the strength requirements of the mine filling.

[0116] For the present mine goaf filling, its main technical requirement is that the 28d compressive strength is greater than or equal to 1.5MPa, and the later period will not cause safety accidents. As can be seen from Table 11, the 28d uniaxial compressive strength of the mine filling cementing material in Examples 1-5 of the present application is far greater than 1.5MPa, fully meeting the strength technical index requirements, and the margin is large, and corresponding adjustment can also be made according to the grading tailings of each mine. And the raw materials in the present application are basically the reuse of solid waste, low cost, environmentally friendly, and can realize large-scale waste recycling, therefore, the mine filling cementing material in the present application can be completely used as a green alternative scheme for the mine goaf filling in the prior art.

[0117] The above has made a detailed description of the embodiments of the present application, but the present application is not limited to the above embodiments, and various changes can be made within the knowledge range possessed by those skilled in the art without departing from the purpose of the present application. In addition, the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

Claims

1. A mine fill cementing material characterised in that: The mine filling cementing material, classified tailings and water are included; the mass ratio of the mine filling cementing material and the classified tailings is 1: (6-10); the solid content of the mine filling cementing material is 64-66%; The mine filling cementing material includes the following raw materials in mass fraction: 62-72 parts of red mud; 5-15 parts of carbide slag; 8-18 parts of desulfurization gypsum; 2-8 parts of bentonite; 2-8 parts of bauxite; The bentonite includes the following components in mass percentage: SiO2 68.51-71.37%, Al2O3 14.58-15.85%, Na2O 3.61-4.18%, Fe2O3 3.29-3.91%, CaO 1.93-2.68%, MgO 1.92-2.16%, K2O 1.00-1.24%, TiO2 0.50-0.67%, and the content of other oxides is less than 2%; The bauxite includes the following components in mass percentage: the content of Al2O3 is greater than 85%, the content of Fe2O3 is less than 2.0%, and the content of TiO2 is less than 4%; The red mud includes the following components in mass percentage: SiO2 18-21%, Al2O3 20-23%, Fe2O3 11-14%, CaO 15-18%, Na2O 5-8%, and the loss on ignition is 22-25%.

2. Mine filling cementing material according to claim 1, characterized in that: The specific surface area of the red mud is 900-1000 m 2 ·kg -1 .

3. Mine filling cementing material according to claim 1, characterized in that: The specific surface area of the desulfurized gypsum and / or carbide slag is 1200-1500 m 2 ·kg -1 .

4. The minefilling cementing material of claim 1, characterized by: The mine filling cementing material is prepared by a preparation method including the following steps: mixing and ball-milling the red mud, the carbide slag, the desulfurization gypsum, the bentonite and the bauxite according to the mass ratio to obtain the mine filling cementing material.

5. A minefill cementitious material according to claim 1 characterised in that: The parameters of the classified tailings are: specific gravity of 3-3.5, loose dry bulk density of 1.5 t / m 3 ~1.8 t / m 3 , compact dry bulk density of 2 t / m 3 ~2.3 t / m 3 , maximum porosity of 45%-50%, minimum porosity of 35%-40%, and natural repose angle of 35°-40°.

6. The use of the mine filling cementing material in any one of claims 1-5 in mine filling material or building material.

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