Modified sandstone plate and preparation method thereof

Abstract

The invention discloses a modified sandstone plate and a preparation method thereof, and relates to the field of building materials.The preparation method comprises the steps that sandstone is activated, an alkaline mixed solution is prepared, solidified matrix slurry is prepared, solidified matrix particles are prepared, aggregate is prepared, matrix material slurry is prepared, and the aggregate and the matrix material slurry are mixed; according to the preparation method, the industrial waste influencing the environment and the soft sandstone which is difficult to apply can be applied to the building board, resource utilization can be carried out, economic benefits are brought, and meanwhile the environmental problem brought by the industrial waste is solved. The modified sandstone plate is formed by mixing the aggregate and the base material slurry, the aggregate is dispersed in the base material slurry, the overall compressive strength of the plate can be enhanced, the periphery of the aggregate is wrapped with the wrapping layer, the aggregate can be prevented from further making contact with external moisture or air, and the influence of the environment on the performance of the aggregate is reduced; and the combination of the aggregate and the matrix material slurry is facilitated, so that the overall performance of the modified sandstone plate is more excellent.

Description

Technical Field

[0001] The invention relates to the field of building materials, and in particular to a modified arsenic sandstone plate and a preparation method thereof. Background Art

[0002] Arsenic sandstone is a loose rock layer, a special loose and broken rock layer with severe weathering. Due to the small thickness and low pressure of the overlying rock layer, it has a low degree of diagenesis, poor cementation between sand particles, and low structural strength. After being eroded by water, the rock structure cannot withstand the expansion effect and collapses. It is the main source of coarse sediment in the Yellow River and its tributaries, and one of the main factors causing soil erosion in the Yellow River. Arsenic sandstone is as hard as stone in a dry state, but collapses into mud when it encounters water, making it difficult to use. The modified materials developed with arsenic sandstone have low engineering strength and are difficult to meet the needs of general civil engineering projects. Summary of the invention

[0003] The purpose of the present invention is to provide a modified arsenic sandstone plate and a preparation method thereof, so as to solve the problem that the above-mentioned arsenic sandstone is difficult to apply.

[0004] To achieve this object, the present invention adopts the following technical solutions:

[0005] The present invention provides a method for preparing a modified arsenic sandstone plate, comprising the following steps:

[0006] Activation of arsenic sandstone: drying the arsenic sandstone, and mechanically grinding the arsenic sandstone to obtain arsenic sandstone powder, and then calcining the arsenic sandstone powder;

[0007] Preparing an alkaline mixed solution: mixing water glass, water and NaOH powder evenly to obtain an alkaline mixed solution, wherein the water glass modulus of the alkaline mixed solution is 1.4 to 1.6;

[0008] Prepare the solidified matrix slurry: mix the activated arsenic sandstone powder and the mineral admixture evenly to obtain a mixed powder; then add the alkaline mixed solution to the mixed powder; after stirring evenly, add the desulfurization ash and the divalent metal substitute, and after stirring evenly, obtain the solidified matrix slurry; the divalent metal substitute includes one or both of magnesium oxide and calcium oxide;

[0009] Preparing solidified matrix particles: pouring solidified matrix slurry into a mold and performing vacuum pressing to form a solidified matrix, and then crushing the solidified matrix into solidified matrix particles;

[0010] Aggregate preparation: mineral admixture, activated arsenic sandstone and alkaline mixed solution are mixed to obtain aggregate slurry; solidified matrix particles are put into the aggregate slurry and allowed to stand, and after the aggregate slurry is solidified, a 0.5-1 mm wrapping layer is formed on the periphery of the solidified matrix particles to obtain aggregate;

[0011] Preparing a matrix material slurry: uniformly mixing the mineral admixture, activated arsenic sandstone, water, water glass and NaOH powder to obtain a matrix material slurry;

[0012] Mixing aggregate and matrix material slurry: mixing the matrix material slurry with the aggregate to form a mixed slurry, and forming it by a high-pressure pressing process to obtain the matrix material; curing the matrix material to obtain the modified arsenic sandstone plate.

[0013] In the preparation method of the modified arsenic sandstone plate, in the step of activating the arsenic sandstone, the rotation speed of the mechanical grinding equipment is 400-600r / min, the grinding time is 10-20min, and the average particle size of the arsenic sandstone powder is 20-28μm; the calcination process includes heating to 600°C at a heating rate of 5°C / min and keeping warm for 2-3h.

[0014] In the preparation method of the modified arsenic sandstone plate, in the step of preparing the alkaline mixed solution, the components of the alkaline mixed solution include 90 to 110 parts of water glass, 90 to 110 parts of water and 20 to 25 parts of NaOH by weight, the water glass modulus of the water glass is 3.0 to 3.5, and the solid content of the water glass is 30% to 35%.

[0015] In the method for preparing the modified arsenic sandstone plate, in the step of preparing solidified matrix particles, the particle size of the solidified matrix particles is 2 to 5 mm.

[0016] In the preparation method of the modified arsenic sandstone plate, the thickness of the wrapping layer is 0.5 to 1 mm, and the standing time is 8 hours to 24 hours.

[0017] In the preparation method of the modified arsenic sandstone plate, in the step of preparing the solidified matrix slurry, the activated arsenic sandstone powder and the mineral admixture are mixed in a mass ratio of (1-1.2): (1-1.2); the components of the solidified matrix slurry include, by weight, 95-105 parts of mixed powder, 65-75 parts of alkaline mixed solution, 10-15 parts of desulfurized ash and 10-15 parts of divalent metal substitute.

[0018] In the preparation method of the modified arsenic sandstone plate, the components of the aggregate slurry include, by weight, 5 to 8 parts of mineral admixture, 2 to 5 parts of arsenic sandstone and 2 to 5 parts of alkaline mixed solution.

[0019] In the preparation method of the modified arsenic sandstone plate, in the step of mixing aggregate and matrix material slurry, the components of the mixed slurry include, by weight, 60 to 70 parts of aggregate, 65 to 75 parts of mineral admixtures, 38 to 42 parts of arsenic sandstone, 16 to 20 parts of water; 8 to 10 parts of water glass and 0.8 to 1.5 parts of NaOH powder, and the water glass modulus of the water glass in the mixed slurry is 1.4 to 1.6.

[0020] In the preparation method of the modified arsenic sandstone plate, the curing temperature is 18-22° C., the curing humidity is ≥90%, and the curing time is 27-29 days.

[0021] The present invention also provides a modified arsenic sandstone plate, which is prepared by the above-mentioned modified arsenic sandstone plate preparation method, and the thickness of the modified arsenic sandstone plate is 20-25 mm, the flexural strength of the modified arsenic sandstone plate after curing for 28 days is 6.65-7.70 MPa, and the compressive strength of the modified arsenic sandstone plate after curing for 28 days is 33.5-37.5 MPa.

[0022] A technical solution in the present invention can have the following beneficial effects:

[0023] (1) The preparation method can use industrial waste that affects the environment and arsenic sandstone that is difficult to use into building panels, which can not only be used as resources and bring economic benefits, but also solve the environmental problems caused by industrial waste.

[0024] (2) The modified arsenic sandstone board is made of a mixture of aggregate and matrix material slurry. Since aggregates are dispersed in the matrix material slurry, the overall compressive strength of the board can be enhanced. Moreover, the outer periphery of the aggregate is wrapped with a wrapping layer, which can prevent the aggregate from further contacting with external moisture or air, reduce the impact of the environment on the performance of the aggregate, and is more conducive to the combination of aggregate and matrix material slurry, so that the overall performance of the modified arsenic sandstone board is better. DETAILED DESCRIPTION

[0025] The technical scheme of the present invention is further illustrated by specific embodiments below. In order to facilitate understanding of the present invention, the present invention is described more comprehensively below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0026] If no specific techniques or conditions are specified in the examples, the techniques or conditions described in the literature in the field or the product instructions are used. If no manufacturer is specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0028] The present invention provides a method for preparing a modified arsenic sandstone plate, comprising the following steps:

[0029] Activation of arsenic sandstone: drying the arsenic sandstone, and mechanically grinding the arsenic sandstone to obtain arsenic sandstone powder, and then calcining the arsenic sandstone powder;

[0030] Preparing an alkaline mixed solution: mixing water glass, water and NaOH powder evenly to obtain an alkaline mixed solution, wherein the water glass modulus of the alkaline mixed solution is 1.4 to 1.6;

[0031] Prepare the solidified matrix slurry: mix the activated arsenic sandstone powder and the mineral admixture evenly to obtain a mixed powder; then add the alkaline mixed solution to the mixed powder; after stirring evenly, add the desulfurization ash and the divalent metal substitute, and after stirring evenly, obtain the solidified matrix slurry; the divalent metal substitute includes one or both of magnesium oxide and calcium oxide;

[0032] Preparing solidified matrix particles: pouring solidified matrix slurry into a mold and performing vacuum pressing to form a solidified matrix, and then crushing the solidified matrix into solidified matrix particles;

[0033] Aggregate preparation: mineral admixture, activated arsenic sandstone and alkaline mixed solution are mixed to obtain aggregate slurry; solidified matrix particles are put into the aggregate slurry and allowed to stand, and after the aggregate slurry is solidified, a 0.5-1 mm wrapping layer is formed on the periphery of the solidified matrix particles to obtain aggregate;

[0034] Preparing a matrix material slurry: uniformly mixing the mineral admixture, activated arsenic sandstone, water, water glass and NaOH powder to obtain a matrix material slurry;

[0035] Mixing aggregate and matrix material slurry: mixing the matrix material slurry with the aggregate to form a mixed slurry, and forming it by a high-pressure pressing process to obtain the matrix material; curing the matrix material to obtain the modified arsenic sandstone plate.

[0036] In the activation step of the arsenic sandstone, the arsenic sandstone can be ground into powder during mechanical grinding, which is conducive to the chemical reaction of the arsenic sandstone during the subsequent calcination process. During the calcination process, some quartz and feldspar impurities in the arsenic sandstone are oxidized, and montmorillonite and mica are decomposed, so that the internal structure of the arsenic sandstone is significantly improved, forming an activated arsenic sandstone powder with a higher active surface.

[0037] The alkaline mixed solution prepared in the step of preparing the alkaline mixed solution is used to perform alkali excitation on the arsenic sandstone powder to improve the mechanical strength of the material.

[0038] In the step of preparing the solidified matrix slurry, the arsenic sandstone powder is first mixed with the mineral admixture, and then the alkaline mixed solution is added. Mixing the arsenic sandstone powder and the mineral admixture evenly first helps to ensure sufficient contact and good dispersion between the two. The mineral admixture contains active silicates, aluminates and other components, which can react with the mineral components of the arsenic sandstone powder in an alkaline environment to form a product with gelling properties, such as CSH gel. Mixing in advance can ensure the uniform distribution of these reaction components and avoid the uneven reaction after the addition of the alkaline mixed solution.

[0039] Mineral admixtures can improve the mechanical properties of arsenic sandstone powder. After the arsenic sandstone powder and the mineral admixture are evenly mixed, an alkaline mixed solution is added for alkali excitation, so that the arsenic sandstone powder and the silicates and aluminates inside the mineral admixture participate in the polymerization reaction to form a product with gelling properties, which is convenient for vacuum pressing in the subsequent preparation of solidified matrix particles. Desulfurization ash contains rich calcium oxide and a certain amount of magnesium oxide. Magnesium oxide or calcium oxide can be introduced through divalent metal substitutes, which can reduce the use of desulfurization ash, reduce the introduction of impurities such as heavy metals and sulfides contained in the desulfurization ash, avoid negative impacts on the performance of the plate, and further improve the stability and compressive properties of the material.

[0040] In the step of preparing the solidified matrix particles, the solidified matrix slurry is poured into a mold, and then the mold is placed in a vacuum press with a pressure set at 15 MPa for 2 to 3 minutes.

[0041] In the step of preparing aggregate, the components of the aggregate slurry include mineral admixtures, pyrophyllite and alkaline mixed solution. Under the stimulation of the alkaline mixed solution, the chemical reaction activity between the pyrophyllite and the mineral admixture in the slurry stimulates the volcanic ash activity of the pyrophyllite, so that the silicates and aluminates inside the pyrophyllite participate in the polymerization reaction to form a product with gelling properties, which can be wrapped around the periphery of the solidified matrix particles after standing to form a coating layer. The coating layer forms a dense film on the surface of the solidified matrix particles, which can prevent the aggregate from further contacting with external moisture or air, and reduce the impact of the environment on the performance of the aggregate. The coating layer reaction can improve the density and strength of the aggregate, and provide better interface properties for the subsequent combination with the matrix material slurry.

[0042] The matrix material slurry prepared in the step of preparing the matrix material slurry is used to combine with the aggregate. The mechanical properties of the material can be significantly improved by combining the matrix material slurry with the aggregate.

[0043] In the step of mixing the aggregate and the matrix material slurry, the high pressure pressing process can refer to the high pressure pressing operation of the existing plate. The pressure range of the high pressure pressing is 8-12MPa; the temperature range of the high pressure pressing is 20-60°C; and the pressing time of the high pressure pressing is 10-15min.

[0044] In a specific embodiment of the present invention, in the steps of preparing the solidified matrix slurry, preparing the aggregate and preparing the matrix material slurry, the mineral admixture is S95 grade mineral powder, and the desulfurization ash is specifically the desulfurization ash of the circulating fluidized bed.

[0045] The preparation method of the modified arsenic sandstone plate comprises four stages: activating the arsenic sandstone, making the arsenic sandstone into solidified matrix particles, forming a coating layer on the solidified matrix particles, and making the plate.

[0046] The stage of activating arsenic sandstone includes the arsenic sandstone activation step, the preparation of alkaline mixed solution and the preparation of solidified matrix slurry. The activity of arsenic sandstone is first improved by mechanical grinding and calcination, and then the activity of arsenic sandstone is stimulated by alkaline mixed solution. Subsequently, desulfurization ash and divalent metal substitutes are added to improve the pore structure of the material and enhance the strength and water resistance of the material. Adding only magnesium oxide and calcium oxide will lead to excessive local reaction, especially the intense heat release of quicklime in contact with water, which may cause rapid coagulation of the slurry. Therefore, desulfurization ash and divalent metal substitutes need to be mixed and used. Desulfurization ash contains other components to avoid excessive local reaction and the generation of a large number of heat beams. In addition, desulfurization ash can not only provide magnesium oxide and calcium oxide, but also enhance the gelling properties, optimize the pore structure, and reduce carbon emissions and material costs.

[0047] The stage of making the arsenic sandstone into solidified matrix particles is specifically a step of preparing solidified matrix particles, forming a solidified matrix by vacuum pressing, and then crushing the solidified matrix into solidified matrix particles.

[0048] The stage of forming a coating layer of the solidified matrix particles is specifically the step of preparing aggregates, first preparing aggregate slurry, and then putting the solidified matrix particles into the aggregate slurry. Since the components of the aggregate slurry include mineral admixtures, arsenic sandstone and alkaline mixed solution, the arsenic sandstone and mineral admixtures in the slurry form products with gelling properties under the stimulation of the alkaline mixed solution, which can adhere to the solidified matrix particles and form a 0.5-1 mm coating layer after standing. Among them, after the solidified matrix particles are put into the aggregate slurry, directly standing still may cause the particles to agglomerate. In a preferred embodiment, the specific steps of standing still include: after the solidified matrix particles are put into the aggregate slurry, slowly stir for 1 minute, and then stand for 3-5 minutes; and appropriately add 0.5-1 parts of water reducer in the aggregate slurry to adjust the rheology of the slurry.

[0049] The stage of making the board includes the steps of preparing the matrix material slurry and mixing the aggregate and the matrix material slurry. The matrix material slurry is mixed with the aggregate. Since a coating layer is attached to the periphery of the aggregate, the matrix material slurry mixed with the mineral admixture, activated pyrite sandstone, water, water glass and NaOH powder can better combine with the aggregate, thereby improving the strength of the modified pyrite sandstone board.

[0050] The preparation method can use industrial waste that affects the environment and arsenic sandstone that is difficult to use into building panels, which can not only be used as resources to bring economic benefits, but also solve the environmental problems caused by industrial waste.

[0051] Specifically, in the step of activating the arsenic sandstone, the rotation speed of the mechanical grinding equipment is 400-600 r / min, the grinding time is 10-20 min, and the average particle size of the arsenic sandstone powder is 20-28 μm; the calcination process includes heating to 600° C. at a heating rate of 5° C. / min and keeping warm for 2-3 hours.

[0052] In specific applications, the method of drying the arsenic sandstone is: put the arsenic sandstone into an oven and dry it at 105°C for 24 hours to ensure complete drying. The mechanical grinding equipment can be a vertical planetary grinding machine, with a speed setting of 400-600r / min and grinding for 10-20min, which can grind the average particle size of the arsenic sandstone to 20-28μm. The above steps can be used to oxidize some quartz and feldspar impurities in the arsenic sandstone, decompose montmorillonite and mica, improve the internal structure of the arsenic sandstone, and provide the activity of the arsenic sandstone.

[0053] Specifically, in the step of preparing the alkaline mixed solution, the components of the alkaline mixed solution include 90 to 110 parts of water glass, 90 to 110 parts of water and 20 to 25 parts of NaOH by weight, the water glass modulus of the water glass is 3.0 to 3.5, and the solid content of the water glass is 30% to 35%.

[0054] The water glass modulus is the ratio of SiO2 to Na2O in the water glass. By adding sodium hydroxide to general industrial water glass to adjust the water glass modulus, its alkalinity can be increased, thereby increasing the reaction efficiency of the alkaline mixed solution and the activated arsenic sandstone powder, forming more gelled products, thereby increasing the strength of the solidified matrix particles.

[0055] Specifically, in the step of preparing the solidified matrix particles, the particle size of the solidified matrix particles is 2 to 5 mm.

[0056] By using the above-mentioned particle size solidified matrix particles, after the coating layer is attached, mixed with the matrix material slurry and pressed under high pressure, a high-strength modified arsenic sandstone plate can be formed, so that the modified arsenic sandstone plate has good compressive strength.

[0057] Specifically, the thickness of the wrapping layer is 0.5 to 1 mm, and the standing time is 8 hours to 24 hours.

[0058] The thickness of the wrapping layer directly affects the bonding strength between the aggregate and the base material. If the thickness is too low, the interface of the wrapping layer may be weakened, affecting the overall structural performance; if the thickness of the wrapping layer is too large, the material cost will increase. A thickness of 0.5 to 1 mm can form a sufficiently dense reaction layer to ensure the continuous hydration reaction of the internal silicate and aluminate. By forming CSH gel and calcium aluminate compounds, the compressive strength, flexural strength and durability of the board are significantly improved, which helps to improve the balanced performance of the material and avoid excessive material costs. The standing time affects the thickness of the wrapping layer. The longer the standing time, the thicker the wrapping layer.

[0059] Specifically, in the step of preparing the solidifying matrix slurry, the activated arsenic sandstone powder and the mineral admixture are mixed in a mass ratio of (1-1.2): (1-1.2); the components of the solidifying matrix slurry, measured in parts by weight, include 95-105 parts of mixed powder, 65-75 parts of alkaline mixed solution, 10-15 parts of desulfurization ash and 10-15 parts of divalent metal substitutes.

[0060] In a specific embodiment of the present invention, the mixing ratio of the activated arsenic sandstone powder and the mineral admixture is 1:1, so that the mixed powder has a dense structure and excellent interface bonding performance, and exhibits good physical and mechanical properties.

[0061] The arsenic sandstone powder and mineral admixtures provide the basic strength and stability required for the solidified matrix particles; the water glass and NaOH in the solidified matrix slurry are used to stimulate the volcanic ash activity of the arsenic sandstone powder and mineral admixtures and promote the formation of cementitious materials; the water in the solidified matrix slurry is used to adjust the overall rheological properties to make it easy to shape and compact.

[0062] Specifically, the components of the aggregate paste include, by weight, 5 to 8 parts of mineral admixture, 2 to 5 parts of arsenic sandstone and 2 to 5 parts of alkaline mixed solution.

[0063] The aggregate paste contains mineral admixtures, arsenic sandstone and alkaline mixed solution to form a coating.

[0064] Specifically, in the step of mixing aggregate and matrix material slurry, the components of the mixed slurry, measured by weight, include 60-70 parts of aggregate, 65-75 parts of mineral admixtures, 38-42 parts of arsenic sandstone, 16-20 parts of water; 8-10 parts of water glass and 0.8-1.5 parts of NaOH powder, and the water glass modulus of the water glass in the mixed slurry is 1.4-1.6.

[0065] With the above components, the aggregate and matrix material slurry can exhibit an optimal balance of strength and rheological properties after being mixed.

[0066] Specifically, the curing temperature is 18-22° C., the curing humidity is ≥90%, and the curing time is 27-29 days.

[0067] The curing process can prevent the board from deformation, warping or cracking due to changes in environmental humidity and temperature, helping the board to maintain its original shape and size and extend its service life. At the same time, it increases compressive strength and toughness: properly cured boards are more durable during use, have stronger compressive resistance and toughness, and are not easily damaged by external forces.

[0068] The present invention also provides a modified arsenic sandstone plate, which is prepared by the above-mentioned modified arsenic sandstone plate preparation method, and the thickness of the modified arsenic sandstone plate is 20-25 mm, the flexural strength of the modified arsenic sandstone plate after curing for 28 days is 6.65-7.70 MPa, and the compressive strength of the modified arsenic sandstone plate after curing for 28 days is 33.5-37.5 MPa.

[0069] The modified arsenic sandstone board is made of a mixture of aggregate and matrix material slurry. Since aggregates are dispersed in the matrix material slurry, the overall compressive strength of the board can be enhanced. Moreover, the outer periphery of the aggregate is wrapped with a wrapping layer, which can prevent the aggregate from further contacting with external moisture or air, reduce the impact of the environment on the performance of the aggregate, and is more conducive to the combination of aggregate and matrix material slurry, making the overall performance of the modified arsenic sandstone board better.

[0070] Example 1

[0071] A method for preparing a modified arsenic sandstone plate comprises the following steps:

[0072] Activation of arsenic sandstone: put the arsenic sandstone into an oven and dry it at 105°C for 24 hours, and then put the arsenic sandstone into a vertical planetary grinder, set the speed to 500r / min, grind for 15 minutes, and obtain arsenic sandstone powder, the average particle size of which is 25μm; then put the ground arsenic sandstone into a muffle furnace, heat it to 600°C at a heating rate of 5°C / min, and keep it warm for 2.5 hours;

[0073] Prepare an alkaline mixed solution: mix 100 parts of water glass with a modulus of 3.3 and a solid content of 32%, 100 parts of water and 25 parts of NaOH powder to obtain an alkaline mixed solution, wherein the water glass modulus of the alkaline mixed solution is 1.5;

[0074] Prepare a solidifying matrix slurry: mix the activated arsenic sandstone powder and the mineral admixture in a mass ratio of 1:1 to obtain a mixed powder; weigh 100 parts of the mixed powder and mix it with 75 parts of an alkaline mixed solution; after stirring evenly, add 10 parts of desulfurization ash, 10 parts of magnesium oxide and 5 parts of calcium oxide, and stir evenly to obtain a solidifying matrix slurry;

[0075] Preparation of solidified matrix particles: pouring the solidified matrix slurry into a mold, placing the mold in a vacuum press, setting the pressure of the vacuum press to 15 MPa, pressing for 2 minutes, and then crushing the solidified matrix into solidified matrix particles with an average particle size of 5 mm;

[0076] Aggregate preparation: 7 parts of mineral admixture, 3 parts of activated arsenic sandstone and 3 parts of alkaline mixed solution are mixed to obtain aggregate slurry; solidified matrix particles are put into the aggregate slurry and allowed to stand, and after the aggregate slurry is solidified, a 0.8 mm wrapping layer is formed on the periphery of the solidified matrix particles to obtain aggregate;

[0077] Prepare the matrix material slurry: mix 70 parts of mineral admixture, 40 parts of activated arsenic sandstone, 18 parts of water, 9 parts of water glass and 1 part of NaOH powder to obtain the matrix material slurry;

[0078] Mixed aggregate and matrix material slurry: weigh 60 parts of aggregate, mix the above-mentioned matrix material slurry with the aggregate to form a mixed slurry, and adopt a high-pressure pressing process to form a mixture, the pressure range of the high-pressure pressing is 10MPa; the temperature range of the high-pressure pressing is 40°C; the pressing time of the high-pressure pressing is 10min, and the matrix material is obtained; the matrix material is cured, the curing temperature is 20±2°C, the curing humidity is 90%, and the curing time is 28 days to obtain a modified arsenic sandstone plate, and the thickness of the modified arsenic sandstone plate is 22mm.

[0079] Example 2

[0080] The steps of Example 2 are the same as those of Example 1, except that in the step of activating the arsenic sandstone, the rotation speed of the mechanical grinding equipment is 400 r / min, the grinding time is 20 min, and the average particle size of the arsenic sandstone powder is 28 μm; the calcination process includes heating the temperature to 600°C at a heating rate of 5°C / min and keeping it warm for 3 hours.

[0081] In the step of preparing the alkaline mixed solution, the components of the alkaline mixed solution include, by weight, 90 parts of water glass with a modulus of 3.5 and a solid content of 32%, 90 parts of water and 20 parts of NaOH.

[0082] In the step of preparing the solidifying matrix slurry, the activated arsenic sandstone powder is mixed with the mineral admixture in a mass ratio of 1:1.2, and the components of the solidifying matrix slurry include 95 parts of mixed powder, 65 parts of alkaline mixed solution, 15 parts of desulfurized ash and 10 parts of magnesium oxide.

[0083] In the step of preparing the aggregate, 5 parts of mineral admixture, 2 parts of activated arsenic sandstone and 2 parts of alkaline mixed solution are mixed to obtain an aggregate slurry;

[0084] In the preparation of the matrix material slurry, the components of the matrix material slurry include, by weight, 70 parts of aggregate, 65 parts of mineral admixtures, 38 parts of arsenic sandstone, 16 parts of water, 8 parts of water glass and 0.8 parts of NaOH powder, and the water glass modulus of the water glass in the mixed slurry is 1.5.

[0085] Example 3

[0086] The steps of Example 3 are the same as those of Example 1, except that in the step of activating the arsenic sandstone, the rotation speed of the mechanical grinding equipment is 600 r / min, the grinding time is 10 min, and the average particle size of the arsenic sandstone powder is 20 μm; the calcination process includes heating the temperature to 600°C at a heating rate of 5°C / min and keeping it warm for 2 hours.

[0087] In the step of preparing the alkaline mixed solution, the components of the alkaline mixed solution include, by weight, 110 parts of water glass with a modulus of 3.5 and a solid content of 35%, 110 parts of water and 23 parts of NaOH.

[0088] In the step of preparing the solidifying matrix slurry, the activated arsenic sandstone powder is mixed with the mineral admixture in a mass ratio of 1.2:1, and the components of the solidifying matrix slurry include 105 parts of mixed powder, 70 parts of alkaline mixed solution, 12 parts of desulfurized ash, 5 parts of magnesium oxide and 5 parts of calcium oxide.

[0089] In the step of preparing the aggregate, 8 parts of mineral admixture, 5 parts of activated arsenic sandstone and 5 parts of alkaline mixed solution are mixed to obtain an aggregate slurry;

[0090] In the preparation of the matrix material slurry, the components of the matrix material slurry include, by weight, 65 parts of aggregate, 75 parts of mineral admixtures, 42 parts of arsenic sandstone, 20 parts of water, 10 parts of water glass and 1.5 parts of NaOH powder, and the water glass modulus of the water glass in the mixed slurry is 1.5.

[0091] Comparative Example 1

[0092] 70 parts of mineral admixtures, 40 parts of activated pyroconite, 18 parts of water, 9 parts of water glass and 1 part of NaOH powder are uniformly mixed to obtain a matrix material slurry; the matrix material slurry is poured into a mold and formed by a high-pressure pressing process, the pressure range of the high-pressure pressing is 10MPa; the temperature range of the high-pressure pressing is 40°C; the pressing time of the high-pressure pressing is 10min, and the matrix material is obtained; the matrix material is cured, the curing temperature is 20±2°C, the curing humidity is 90%, and the curing time is 28 days, to obtain a pyroconite plate.

[0093] On the 3rd, 7th and 28th days of curing, the flexural strength test and the compressive strength test were carried out on the arsenic sandstone plate and the modified arsenic sandstone plate prepared in Examples 1 to 3. The results are shown in Table 1.

[0094] The flexural strength test and compressive strength test were carried out in accordance with "Cement Mortar Strength Test Method ISO" (GB / T17671-2021). The test adopted displacement control, and the loading rates of the flexural strength test and compressive strength test were 0.12mm / min and 1.3mm / min respectively.

[0095] Table 1 - Test results

[0096]

[0097] By comparing Examples 1 to 3 with Comparative Example 1, the modified arsenic sandstone plate has good flexural strength and compressive strength.

[0098] The technical principle of the present invention is described above in conjunction with specific embodiments. These descriptions are only for explaining the principle of the present invention and cannot be interpreted as limiting the scope of protection of the present invention in any way. Based on the explanations herein, those skilled in the art can associate other specific embodiments of the present invention without creative work, and these equivalent variations or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A method for preparing a modified arsenic sandstone plate, characterized in that: The following steps are involved: Activation of arsenic sandstone: drying the arsenic sandstone, and mechanically grinding the arsenic sandstone to obtain arsenic sandstone powder, and then calcining the arsenic sandstone powder; Preparing an alkaline mixed solution: mixing water glass, water and NaOH powder evenly to obtain an alkaline mixed solution, wherein the water glass modulus of the alkaline mixed solution is 1.4 to 1.6; Prepare the solidified matrix slurry: mix the activated arsenic sandstone powder and the mineral admixture evenly to obtain a mixed powder; then add the alkaline mixed solution to the mixed powder; after stirring evenly, add the desulfurization ash and the divalent metal substitute, and after stirring evenly, obtain the solidified matrix slurry; the divalent metal substitute includes one or both of magnesium oxide and calcium oxide; Preparing solidified matrix particles: pouring solidified matrix slurry into a mold and performing vacuum pressing to form a solidified matrix, and then crushing the solidified matrix into solidified matrix particles; Aggregate preparation: mineral admixture, activated arsenic sandstone and alkaline mixed solution are mixed to obtain aggregate slurry; solidified matrix particles are put into the aggregate slurry and allowed to stand, and after the aggregate slurry is solidified, a 0.5-1 mm wrapping layer is formed on the periphery of the solidified matrix particles to obtain aggregate; Preparing a matrix material slurry: uniformly mixing the mineral admixture, activated arsenic sandstone, water, water glass and NaOH powder to obtain a matrix material slurry; Mixing aggregate and matrix material slurry: mixing the matrix material slurry with the aggregate to form a mixed slurry, and forming it by a high-pressure pressing process to obtain the matrix material; curing the matrix material to obtain the modified arsenic sandstone plate.

2. The method for preparing a modified arsenic sandstone plate according to claim 1, characterized in that: In the step of activating the arsenic sandstone, the rotation speed of the mechanical grinding equipment is 400-600r / min, the grinding time is 10-20min, and the average particle size of the arsenic sandstone powder is 20-28μm; the calcination process includes heating to 600℃ at a heating rate of 5℃ / min and keeping warm for 2-3h.

3. The method for preparing a modified arsenic sandstone plate according to claim 1, characterized in that: In the step of preparing the alkaline mixed solution, the components of the alkaline mixed solution include 90-110 parts of water glass, 90-110 parts of water and 20-25 parts of NaOH by weight, the water glass modulus of the water glass is 3.0-3.5, and the solid content of the water glass is 30%-35%.

4. The method for preparing a modified arsenic sandstone plate according to claim 1, characterized in that: In the step of preparing the solidified matrix particles, the particle size of the solidified matrix particles is 2 to 5 mm.

5. The method for preparing a modified arsenic sandstone plate according to claim 1, characterized in that: The thickness of the wrapping layer is 0.5 to 1 mm, and the standing time is 8 to 24 hours.

6. The method for preparing a modified arsenic sandstone plate according to claim 1, characterized in that: In the step of preparing the solidifying matrix slurry, the activated arsenic sandstone powder and the mineral admixture are mixed in a mass ratio of (1-1.2): (1-1.2); the components of the solidifying matrix slurry, measured by weight, include 95-105 parts of mixed powder, 65-75 parts of alkaline mixed solution, 10-15 parts of desulfurization ash and 10-15 parts of divalent metal substitute.

7. The method for preparing a modified arsenic sandstone plate according to claim 1, characterized in that: The components of the aggregate paste include, by weight, 5 to 8 parts of mineral admixture, 2 to 5 parts of arsenic sandstone and 2 to 5 parts of alkaline mixed solution.

8. The method for preparing a modified arsenic sandstone plate according to claim 1, characterized in that: In the step of mixing the aggregate and matrix material slurry, the components of the mixed slurry, measured by weight, include 60 to 70 parts of aggregate, 65 to 75 parts of mineral admixtures, 38 to 42 parts of activated arsenic sandstone, 16 to 20 parts of water; 8 to 10 parts of water glass and 0.8 to 1.5 parts of NaOH powder, and the water glass modulus of the water glass in the mixed slurry is 1.4 to 1.

6.

9. The method for preparing a modified arsenic sandstone plate according to claim 1, characterized in that: The curing temperature is 18-22° C., the curing humidity is ≥90%, and the curing time is 27-29 days.

10. A modified arsenic sandstone plate, characterized in that: The modified arsenic sandstone plate is prepared by the preparation method of the modified arsenic sandstone plate described in any one of claims 1 to 9, and the thickness of the modified arsenic sandstone plate is 20 to 25 mm, the flexural strength of the modified arsenic sandstone plate after curing for 28 days is 6.65 to 7.70 MPa, and the compressive strength of the modified arsenic sandstone plate after curing for 28 days is 33.5 to 37.5 MPa.

Images