A method for preparing non-fired bricks using semi-dry desulfurized ash

Abstract

This application relates to a method for preparing non-fired bricks using semi-dry desulfurized ash. The method includes: obtaining activated red mud slurry; performing a first mixing and stirring on the activated red mud slurry and the semi-dry desulfurized ash, followed by solid-liquid separation to obtain a mixed solid material; performing a second mixing and stirring on the mixed solid material, a solid waste containing active silicon, and an additive, followed by molding to obtain a non-fired brick blank; and performing steam and oxygen curing on the non-fired brick blank to obtain a non-fired brick. The content of this application solves the technical problem of the low utilization rate of existing semi-dry desulfurized ash.

Description

Technical Field

[0001] The present application relates to the technical field of semi-dry desulfurization ash recycling, and in particular to a method for preparing unburned bricks using semi-dry desulfurization ash. Background Art

[0002] Semi-dry desulfurization technology is widely used in water-scarce areas and areas where old units are being renovated due to its compact structure, small footprint, low one-time investment, low water and power consumption, and no need for anti-corrosion equipment.

[0003] Semi-dry desulfurization ash contains a large amount of calcium sulfite, which has small particle size, high viscosity and unstable properties. It not only affects its recycling desulfurization efficiency, but also has a great impact on the utilization method, scope and channel of desulfurization ash. Desulfurization ash containing a large amount of calcium sulfite is difficult to be used in traditional building materials industries such as cement, concrete, and brick making. Summary of the Invention

[0004] The present application provides a method for preparing unburned bricks using semi-dry desulfurization ash to solve the technical problem of low utilization rate of existing semi-dry desulfurization ash.

[0005] In a first aspect, the present application provides a method for preparing unburned bricks using semi-dry desulfurization ash, the method comprising:

[0006] obtaining activated red mud slurry;

[0007] The activated red mud slurry and the semi-dry desulfurization ash are first mixed and stirred, and then solid-liquid separation is performed to obtain a mixed solid material;

[0008] The mixed solid material is mixed with solid waste containing active silicon and additives for a second time, and then formed to obtain unfired bricks;

[0009] The unburned brick blank is subjected to steam oxygen curing to obtain the unburned brick.

[0010] Optionally, the solid waste containing active silicon includes at least one of the following: fly ash and silicon slag.

[0011] Optionally, the additive is a material that stimulates the gelling properties of the raw material.

[0012] Optionally, the material that stimulates the gelling property of the raw material includes at least one of the following: water glass, cement, sodium aluminate, and polyvinyl alcohol.

[0013] Optionally, the chemical components of the semi-dry desulfurization ash include: calcium sulfite and calcium sulfate; wherein, in terms of mass fraction,

[0014] The content of calcium sulfite is less than 20%, and the content of calcium sulfate is greater than 5%; and / or,

[0015] The chemical components of the red mud include: sodium oxide, aluminum oxide and iron oxide; wherein, by mass fraction,

[0016] The content of the sodium oxide is 2% to 5%, the content of the aluminum oxide is 20% to 30%, and the content of the iron oxide is 20% to 30%.

[0017] Optionally, in parts by weight, the semi-dry desulfurization ash is 16.7 to 40 parts, the red mud is 40 to 67 parts, the solid waste containing active silicon is 14.3 to 25 parts, and the additive is 1 to 5 parts.

[0018] Optionally, the volume concentration of oxygen in the steam oxygen curing is 30% to 70%.

[0019] Optionally, obtaining the activated red mud slurry comprises:

[0020] Obtain red mud slurry; wherein the liquid-to-solid ratio of the red mud slurry is (4-8):1,

[0021] The red mud slurry is activated to obtain activated red mud slurry.

[0022] Optionally, the activation process parameters include: temperature of 60° C. to 90° C., stirring speed of 100 r / min to 400 r / min, and time of 1 h to 3 h.

[0023] Optionally, the first mixing and stirring time is 4 hours to 6 hours, and / or the second mixing and stirring time is 0.5 hours to 2 hours.

[0024] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0025] The method for preparing unburned bricks using semi-dry desulfurization ash provided in the embodiment of the present application has the effect of dealkalizing the activated red mud by the calcium oxide in the semi-dry desulfurization ash, and the desulfurization ash generates free Ca during mixing and stirring. 2+ 、SO4 2- Group, cooperatively released OH - The additive chemically reacts with SiO2 and Al2O3 in red mud and solid waste containing active silicon to produce aluminosilicate reaction products such as hydrated silicic acid, hydrated calcium aluminate, or hydrated calcium sulfoaluminate, thereby improving the strength of unfired bricks. The additive promotes the decomposition and repolymerization of aluminosilicates in red mud and solid waste containing active silicon, generating long chains of aluminosilicates that bond together to form a high-strength, integral whole, thus improving the strength of unfired bricks. The active iron in the red mud cooperates with steam oxygen curing to catalyze the conversion of calcium sulfite in semi-dry desulfurization ash into calcium sulfate, thereby increasing the hardness and compressive strength of unfired bricks. In summary, this solves the technical problem of low utilization of existing semi-dry desulfurization ash. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0027] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0028] Figure 1 A schematic flow chart of a method for preparing unburned bricks using semi-dry desulfurization ash provided in an embodiment of the present application. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0030] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity and should not be understood as a hard limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numbers within the range. For example, the description of a range from 1 to 6 should be considered to have specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which applies regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0031] In this application, unless otherwise stated, the orientation terms such as "upper" and "lower" specifically refer to the drawing directions in the attached drawings. Additionally, in the description of this application's specification, terms such as "including" and "comprising" mean "including but not limited to". In this text, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this text, "and / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. Where A and B can be singular or plural. In this text, "at least one" means one or more, and "multiple" means two or more. "At least one kind", "at least one of the following items (pieces)" or similar expressions refer to any combination of these items, including any combination of single items (pieces) or plural items (pieces). For example, "at least one of a, b, or c", or, "at least one of a, b, and c" can both represent: a, b, c, a - b (i.e., a and b), a - c, b - c, or a - b - c, where a, b, and c can be single or multiple respectively.

[0032] Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment, etc. used in this application can be obtained through market purchases or can be prepared by existing methods.

[0033] In a first aspect, this application provides a method for preparing non - fired bricks using semi - dry desulfurized ash. Please refer to Figure 1 , and the method includes:

[0034] S1. Obtain an activated red mud slurry;

[0035] In some embodiments, obtaining the activated red mud slurry includes:

[0036] Obtain a red mud slurry; wherein, the liquid - to - solid ratio in the red mud slurry is (4 - 8):1,

[0037] Activate the red mud slurry to obtain an activated red mud slurry.

[0038] In some embodiments, the process parameters of the activation include: the temperature is 60°C - 90°C, the stirring speed is 100 r / min - 400 r / min, and the time is 1 h - 3 h.

[0039] In the embodiments of the present application, under the conditions of a suitable liquid-solid ratio, the red mud is fully activated to facilitate the subsequent coordinated dealkalization with desulfurization ash. Excessive red mud usage may cause the red mud slurry to be too viscous and unevenly activated; too little red mud usage may increase the volume of the red mud slurry, increasing the energy consumption for activation and subsequent liquid-solid separation. The above-mentioned activation process parameters can achieve the purpose of red mud slurry activation without causing energy waste. Specifically, the above-mentioned liquid-solid ratio can be 4:1, 5:1, 6:1, 7:1, 8:1, etc., the above-mentioned temperature can be 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, etc., the above-mentioned stirring speed can be 60r / min, 65r / min, 70r / min, 75r / min, 80r / min, 85r / min, 90r / min, etc., and the above-mentioned time can be 1h, 2h, 3h, etc.

[0040] S2, mixing the activated red mud slurry with the semi-dry desulfurization ash for a first time, and then performing solid-liquid separation to obtain a mixed solid material;

[0041] In the embodiment of the present application, a belt conveyor is used for the above-mentioned liquid-solid separation, and the separated liquid is evaporated to recover alkali. The semi-dry desulfurization ash contains a certain proportion of calcium oxide, which has a certain dealkalization effect on the activated red mud. The dealkalized red mud has reduced adhesion and water absorption, making it more suitable for the preparation of building materials. Recovery of alkali in the filtrate also generates certain benefits.

[0042] In some embodiments, the chemical components of the semi-dry desulfurization ash include: calcium sulfite and calcium sulfate; wherein, by mass fraction,

[0043] The content of calcium sulfite is less than 20%, and the content of calcium sulfate is greater than 5%; and / or,

[0044] The chemical components of the red mud include: sodium oxide, aluminum oxide and iron oxide; wherein, by mass fraction,

[0045] The content of the sodium oxide is 2% to 5%, the content of the aluminum oxide is 20% to 30%, and the content of the iron oxide is 20% to 30%.

[0046] In the embodiments of the present application, controlling the chemical components of semi-dry desulfurized ash and red mud ensures the quality of the non-fired bricks. Calcium sulfite in the components of semi-dry desulfurized ash and sodium oxide in the components of red mud have a negative impact on the quality of non-fired bricks. The higher the contents of calcium sulfite and sodium oxide, the lower the compressive and flexural strengths of the non-fired bricks; calcium sulfate in the components of semi-dry desulfurized ash and aluminum oxide and iron oxide in the components of red mud have a positive impact on the quality of non-fired bricks. The higher the contents of calcium sulfate, aluminum oxide and iron oxide, the higher the compressive and flexural strengths of the non-fired bricks. Specifically, the content of the above-mentioned calcium sulfite can be 19%, 18%, 17%, 16%, etc., and the content of the above-mentioned calcium sulfate can be 6%, 7%, 8%, 9%, etc.; the content of the above-mentioned sodium oxide can be 2%, 3%, 4%, 5%, etc., the content of the above-mentioned aluminum oxide can be 20%, 22%, 24%, 26%, 28%, 30%, and the content of the above-mentioned iron oxide can be 20%, 22%, 24%, 26%, 28%, 30%, etc.

[0047] In some embodiments, by weight, the semi-dry desulfurized ash is 16.7 parts to 40 parts, the red mud is 40 parts to 67 parts, the solid waste containing active silicon is 14.3 parts to 25 parts, and the additive is 1 part to 5 parts.

[0048] In the embodiments of the present application, an appropriate amount of red mud enables sufficient activation. On the premise of ensuring the properties of the non-fired bricks, the dosage of semi-dry desulfurized ash is maximized to realize its resource utilization; if the dosage of the semi-dry desulfurized ash is too much, the compressive and flexural strengths of the prepared non-fired bricks may be insufficient due to insufficient oxidation of the desulfurized ash, and it is easy to crack after long-term storage; if the dosage of the semi-dry desulfurized ash is too low, the synergistic effect with materials such as red mud and solid waste containing active silicon may be reduced, the product quality may be reduced, and the utilization amount of semi-dry desulfurized ash may be reduced. The solid waste containing active silicon provides active silicon and reacts with Ca 2+ , SO4 2- and Na +Combining to generate C-S-H gel, ettringite and natrolite increases the setting property of the raw materials. If the dosage of the solid waste containing active silicon is too high, it may increase the production cost and cause waste of resources; if the dosage of the solid waste containing active silicon is too low, it may affect the content of active substances in the raw materials and reduce the strength of the non-fired bricks. The additive accelerates the dissolution of aluminosilicates in red mud and the solid waste containing active silicon, promotes the process of decomposition-repolymerization of solid raw materials, promotes the polymerization reaction of silicon-aluminum monomers, and increases the strength of the non-fired brick blank. If the dosage of the additive is too high, it may increase the production cost and cause waste of resources; if the dosage of the additive is too low, it may reduce the bonding and gelling properties of the raw materials and reduce the product strength. Specifically, the above semi-dry desulfurized ash can be 16.7 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, etc., the above red mud can be 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 67 parts, etc., the above solid waste containing active silicon can be 14.3 parts, 15 parts, 20 parts, 25 parts, etc., and the above additive can be 1 part, 2 parts, 3 parts, 4 parts, 5 parts, etc.

[0049] S3. Secondarily mix and stir the mixed solid materials with the solid waste containing active silicon and the additive, and then perform molding to obtain a non-fired brick blank;

[0050] In the embodiment of the present application, the above molding includes loading the mixture after the second mixing and stirring into a mold, vibrating and compacting it, drying it at room temperature for 2 hours, and then demolding.

[0051] In some embodiments, the solid waste containing active silicon includes at least one of the following: fly ash, silicon slag.

[0052] In the embodiment of the present application, the above solid waste containing active silicon provides active substances to react with CaO in the desulfurized ash and Al2O3 in the red mud to generate products such as aluminosilicates and calcium silicoaluminate with a stable lattice structure that are beneficial to improving the performance of non-fired bricks. Among them, fly ash can not only provide active silicon but also active aluminum; silicon slag can provide active silicon.

[0053] In some embodiments, the additive is a material that stimulates the gelling property of the raw materials.

[0054] In some embodiments, the material that stimulates the gelling property of the raw materials includes at least one of the following: water glass, cement, sodium aluminate, polyvinyl alcohol.

[0055] In the embodiment of the present application, the additive promotes the decomposition-repolymerization of aluminosilicates in red mud and the solid waste containing active silicon, generates long chains of silicate aluminates, and mutually cements to form a high-strength whole, increasing the strength of the non-fired brick blank. It is preferably a material that stimulates the gelling property of the raw materials, which has the effect of increasing the bonding property of the raw materials and improving the quick-setting performance of the raw materials. Specifically, water glass and polyvinyl alcohol with bonding properties, as well as cement and sodium aluminate with quick-setting properties, can be selected.

[0056] In some embodiments, the time of the first mixing and stirring is 4 h to 6 h, and / or the time of the second mixing and stirring is 0.5 h to 2 h.

[0057] In the embodiments of the present application, for the time of the first mixing and stirring and the time of the second mixing and stirring, the stirring time is minimized on the premise of ensuring sufficient reaction of the raw materials. Specifically, the time of the first mixing and stirring can be 4 h, 5 h, 6 h, etc., and the time of the second mixing and stirring can be 0.5 h, 1 h, 1.5 h, 2 h, etc. Both the first mixing and stirring and the second mixing and stirring can be carried out at room temperature, which can be 20°C to 30°C.

[0058] S4. Steam oxygen cure the unfired brick blank to obtain an unfired brick.

[0059] In some embodiments, the volume concentration of oxygen in the steam oxygen curing is 30% to 70%.

[0060] In the embodiments of the present application, a suitable volume concentration of oxygen can not only complete the catalytic oxidation of calcium sulfite contained in the semi-dry desulfurized ash in the raw materials, but also will not cause waste of resources and potential safety hazards. If the volume concentration of oxygen is too high, it may lead to increased costs, waste of resources, and potential safety hazards; if the volume concentration of oxygen is too low, it may affect the catalytic oxidation of calcium sulfite in the desulfurized ash, reduce the strength of the unfired brick, and cause the unfired brick to crack after long-term placement. The activated red mud slurry contains a certain concentration of active iron, which, in coordination with the steam oxygen environment, has a catalytic effect on the oxidation of calcium sulfite in the semi-dry desulfurized ash to calcium sulfate. The reduction of the alkali content in the red mud and the reduction of calcium sulfite and the increase of calcium sulfate content in the desulfurized ash have a promoting effect on the compressive strength, flexural strength of the unfired brick and the increase of the dosage of the semi-dry desulfurized ash. Specifically, the volume concentration of oxygen in the steam oxygen curing can be 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, etc. During the above steam oxygen curing, the humidity is maintained at 40% to 80%, the temperature is 80°C to 120°C, and the curing time is 4 hours to 6 hours. The compressive strength of the cured unfired brick can reach 10.35 to 23.72 MPa, and the flexural strength can reach 6.8 to 13.9 MPa.

[0061] The following further elaborates the present application in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present application and not to limit the scope of the present application. The experimental methods without specific conditions noted in the following embodiments are generally determined according to national standards. If there is no corresponding national standard, they are carried out according to general international standards, conventional conditions, or conditions recommended by the manufacturer.

[0062] The embodiments of the present application provide a method for preparing an unfired brick using semi-dry desulfurized ash, and the method includes:

[0063] S11, obtaining activated red mud slurry;

[0064] S21, first mixing and stirring the activated red mud slurry and the semi-dry desulfurization ash, and then performing solid-liquid separation to obtain a mixed solid material;

[0065] S31, performing a second mixing and stirring of the mixed solid material with solid waste containing active silicon and additives, and then forming the mixed solid material to obtain unfired bricks;

[0066] S41, steam-curing the unfired brick to obtain an unfired brick. Specific process steps are described in Examples 1 to 5.

[0067] Example 1

[0068] The main components of semi-dry desulfurization ash and red mud from a Shanxi enterprise are shown in Table 1 below:

[0069] Table 1 Chemical composition of semi-dry desulfurization ash and red mud of Example 1 (wt%)

[0070]

[0071] Add 4 times the weight of water to the red mud, stir at 80°C for 1 hour for activation pretreatment, add semi-dry desulfurization ash with a mass ratio of 1:1 to red mud, continue stirring at 100r / min for 4 hours, use a belt conveyor for liquid-solid separation, evaporate the separated liquid to recover alkali, add fly ash with a mass ratio of 1:1 to red mud and 1.2% cement to the filter cake, stir for 0.5 hour, put into a detachable mold, vibrate and dry at room temperature for 2 hours, demold and steam oxygen treatment, keep the humidity in the curing box at 70%, the temperature at 80°C, the oxygen volume concentration at 40%, and maintain for 6 hours.

[0072] Example 2

[0073] The main components of the semi-dry desulfurization ash and red mud of a Xinjiang enterprise are shown in Table 2:

[0074] Table 2 Chemical composition of semi-dry desulfurization ash and red mud of Example 2 (wt%)

[0075]

[0076] Add 8 times the amount of water by weight to the red mud, stir at 80 °C for 1 hour for activation pretreatment, add semi-dry desulfurized ash with a mass ratio of 1:2 to the red mud, continue to stir at 100 r / min for 4 hours, perform liquid-solid separation with a belt conveyor, evaporate and recover alkali from the separated liquid, add fly ash with a mass ratio of 1:2 to the red mud and 1% polyvinyl alcohol to the filter cake, stir for 0.5 hours, then load into a split mold, compact, dry at room temperature for 2 hours, demold and perform steam oxygen treatment, keep the humidity in the curing box at 60%, the temperature at 100 °C, the oxygen volume concentration at 50%, and cure for 5 hours.

[0077] Example 3

[0078] Semi-dry desulfurized ash and red mud from an enterprise in Gansu, the main components are shown in Table 3:

[0079] Table 3 Chemical composition (wt%) of semi-dry desulfurized ash and red mud in Example 3

[0080]

[0081] Add 6 times the amount of water by weight to the red mud, stir at 80 °C for 1 hour for activation pretreatment, add semi-dry desulfurized ash with a mass ratio of 1:1 to the red mud, continue to stir at 100 r / min for 4 hours, perform liquid-solid separation with a belt conveyor, evaporate and recover alkali from the separated liquid, add fly ash with a mass ratio of 1:2 to the red mud, 1% polyvinyl alcohol and 2% sodium aluminate to the filter cake, stir for 0.5 hours, then load into a split mold, compact, dry at room temperature for 2 hours, demold and perform steam oxygen treatment, keep the humidity in the curing box at 60%, the temperature at 100 °C, the oxygen volume concentration at 50%, and cure for 5 hours.

[0082] Example 4

[0083] Semi-dry desulfurized ash and red mud from an enterprise in Shanxi, the main components are shown in Table 4:

[0084] Table 4 Chemical composition (wt%) of semi-dry desulfurized ash and red mud in Example 4

[0085]

[0086] Add 6 times the weight of water to the red mud, stir at 80°C for 1 hour for activation pretreatment, add semi-dry desulfurization ash with a mass ratio of 1:2 to red mud, continue stirring at 100r / min for 4 hours, use a belt conveyor for liquid-solid separation, evaporate the separated liquid to recover alkali, add fly ash with a mass ratio of 1:2 to red mud, 1.2% cement and 0.5% sodium aluminate to the filter cake, stir for 0.5 hour, then put into a detachable mold, vibrate and dry at room temperature for 2 hours for demolding and steam oxygen treatment, keep the humidity in the curing box at 40%, the temperature at 80°C, the oxygen volume concentration at 30%, and maintain for 4 hours.

[0087] Example 5

[0088] The main components of semi-dry desulfurization ash and red mud from a Shanxi enterprise are shown in Table 5:

[0089] Table 5 Chemical composition of semi-dry desulfurization ash and red mud of Example 5 (wt%)

[0090]

[0091]

[0092] Add 6 times the weight of water to the red mud, stir at 80°C for 1 hour for activation pretreatment, add semi-dry desulfurization ash with a mass ratio of 1:4 to red mud, continue stirring at 100r / min for 4 hours, use a belt conveyor for liquid-solid separation, evaporate the separated liquid to recover alkali, add fly ash with a mass ratio of 1:4 to red mud, 2% polyvinyl alcohol and 3% water glass to the filter cake, stir for 0.5 hour, then put into a detachable mold, vibrate and dry at room temperature for 2 hours for demolding and steam oxygen treatment, keep the humidity in the curing box at 80%, the temperature at 100°C, the oxygen volume concentration at 70%, and maintain for 6 hours.

[0093] Comparative Example 1

[0094] The main components of semi-dry desulfurization ash and red mud from a Shanxi enterprise are shown in Table 6:

[0095] Table 6 Chemical composition (wt%) of semi-dry desulfurization ash and red mud of Comparative Example 1

[0096]

[0097] Add 4 times the weight of water to the red mud, stir at 80°C for 1 hour for activation pretreatment, add semi-dry desulfurization ash with a mass ratio of 1:1 to red mud, continue stirring at 100r / min for 4 hours, use a belt conveyor for liquid-solid separation, evaporate the separated liquid to recover alkali, add fly ash with a mass ratio of 1:1 to red mud and 1.2% cement to the filter cake, stir for 0.5 hour, then put into a detachable mold, vibrate and dry at room temperature for 2 hours for demolding and curing, keep the humidity in the curing box at 70%, the temperature at 80°C, and the curing period is 6 hours.

[0098] Comparative Example 2

[0099] The main components of semi-dry desulfurization ash and red mud from a Shanxi enterprise are shown in Table 7:

[0100] Table 7 Chemical composition (wt%) of semi-dry desulfurization ash and red mud of Comparative Example 2

[0101]

[0102] Add 4 times the weight of water to the red mud, stir at 80°C for 1 hour for activation pretreatment, add semi-dry desulfurization ash with a mass ratio of 1:1 to red mud, continue stirring at 100r / min for 4 hours, use a belt conveyor for liquid-solid separation, evaporate the separated liquid to recover alkali, add fly ash with a mass ratio of 1:1 to red mud and 1.2% cement to the filter cake, stir for 0.5 hour, then put into a detachable mold, vibrate and dry at room temperature for 2 hours for demolding and steam oxygen treatment, keep the humidity in the curing box at 70%, the temperature at 80°C, the oxygen volume concentration at 40%, and maintain for 6 hours.

[0103] Comparative Example 3

[0104] The main components of semi-dry desulfurization ash and red mud from a Shanxi enterprise are shown in Table 8:

[0105] Table 8 Chemical composition (wt%) of semi-dry desulfurization ash and red mud of Comparative Example 3

[0106]

[0107] Add 2 times the weight of water to the red mud, stir at 80°C for 1 hour for activation pretreatment, add semi-dry desulfurization ash with a mass ratio of 1:1 to red mud, continue stirring at 100r / min for 4 hours, use a belt conveyor for liquid-solid separation, evaporate the separated liquid to recover alkali, add fly ash with a mass ratio of 1:1 to red mud and 1.2% cement to the filter cake, stir for 0.5 hour, then put into a detachable mold, vibrate and dry at room temperature for 2 hours for demolding and curing, keep the humidity in the curing box at 70%, the temperature at 80°C, and maintain the curing for 6 hours.

[0108] The unfired bricks processed in Examples 1-5 and Comparative Examples 1-3 were tested for compressive strength and flexural strength, and the test results are shown in Table 9 below:

[0109] Table 9 Test Results of Compressive Strength and Flexural Strength of Unfired Bricks

[0110]

[0111]

[0112] As can be seen from Table 9 above, for the unfired bricks prepared by the process method provided in the embodiments of the present application, their compressive strength is greater than 10 MPa and their flexural strength is greater than 6 MPa; by comparing the comparative examples and the embodiments, it can be obtained that when the raw material parameters do not meet the requirements or a certain process parameter is not within the scope of the embodiments of the present application during the treatment process, oxygen curing was not carried out in Comparative Example 1; the composition of red mud changed in Comparative Example 2, and the iron oxide content was too low, resulting in a reduced catalytic effect; the liquid-solid ratio of the red mud slurry was too small in Comparative Example 3, and in all cases, the oxidation of semi-dry desulfurized ash was incomplete to a certain extent, resulting in a decrease in the compressive strength and flexural strength of the unfired bricks.

[0113] The above are only specific embodiments of the present application, enabling those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for preparing non-fired bricks using semi-dry desulfurized ash, characterized in that, The method includes: obtaining red mud slurry; activating the red mud slurry to obtain activated red mud slurry; conducting first mixing and stirring on the activated red mud slurry and semi-dry desulfurized ash, and then performing solid-liquid separation to obtain mixed solid materials; conducting second mixing and stirring on the mixed solid materials, solid waste containing active silicon and additives, and then performing forming to obtain unfired brick blanks; performing steam-oxygen curing on the unfired brick blanks to obtain unfired bricks; wherein, the liquid-solid ratio in the red mud slurry is (4-8):1, and the activation temperature is 60°C - 90°C; by weight, the semi-dry desulfurized ash is 16.7 parts - 40 parts, the red mud is 40 parts - 67 parts, the solid waste containing active silicon is 14.3 parts - 25 parts, and the additive is 1 part - 5 parts; by mass fraction, the chemical components of the semi-dry desulfurized ash include: by mass fraction, the content of calcium sulfite is less than 20%, and the content of calcium sulfate is greater than 5%; the chemical components of the red mud include: the content of sodium oxide is 2% - 5%, the content of aluminum oxide is 20% - 30%, and the content of iron oxide is 20% - 30%; in the steam-oxygen curing, the volume concentration of oxygen is 30% - 70%, the humidity is 40% - 80%, the temperature is 80°C - 120°C, and the curing time is 4 hours - 6 hours; the compressive strength of the unfired brick after curing is 10.35 - 23.72 MPa, and the flexural strength is 6.8 - 13.9 MPa.

2. The method according to claim 1, wherein The solid waste containing active silicon includes at least one of the following: fly ash, silicon slag.

3. The method according to claim 1, characterized in that, The additive is a material for activating the gelling property of raw materials.

4. The method according to claim 3, characterized in that, The material for activating the gelling property of raw materials includes at least one of the following: water glass, cement, sodium aluminate, polyvinyl alcohol.

5. The method according to claim 1, wherein The process parameters of the activation include: the stirring speed is 100 r / min - 400 r / min, and the time is 1 h - 3 h.

6. The method according to claim 1, wherein The time of the first mixing and stirring is 4 h - 6 h, and / or the time of the second mixing and stirring is 0.5 h - 2 h.

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