A titanium gypsum curing agent, preparation method and application

Abstract

The present invention provides a titanium gypsum curing agent, a preparation method and an application, belonging to the technical field of road engineering materials. By weight, the raw materials include: 30-50 parts of an activator, 10-15 parts of a filling material, 30-50 parts of an active solid waste material, 1-10 parts of calcium oxide, and 2-5 parts of a dispersant; the activator includes agent A and agent B with a mass ratio of 0.025-0.08; agent A includes sodium hydroxide and potassium hydroxide; agent B includes composite portland cement and ordinary portland cement. By fully utilizing the synergistic hydration and hardening effect among the solid waste raw materials, through the double salt effect and the silicon four-coordination isomorphous effect among the solid waste raw materials, it can have a synergistic activation effect with titanium gypsum, form compounds or solid solutions with certain strength and stability, physically wrap the harmful substances in the titanium gypsum, realize the effective solidification of the harmful substances in the titanium gypsum, and generate a certain road use strength.

Description

Technical Field

[0001] The present invention belongs to the technical field of road engineering materials, and particularly relates to a titanium gypsum curing agent, a preparation method and an application thereof. Background Art

[0002] Disclosing the information of this background art section is only intended to increase the understanding of the overall background of the present invention, and is not necessarily regarded as an admission or an implication in any form that this information constitutes the prior art already known to those of ordinary skill in the art.

[0003] Titanium gypsum is a waste residue generated by adding lime (or carbide slag) to neutralize a large amount of acidic wastewater during the production of titanium dioxide by the sulfuric acid method. Its main component is calcium sulfate dihydrate, and usually contains a large amount of impurities such as ferrous sulfate. At present, the treatment method of titanium gypsum is still mainly stacking or landfill, which occupies a large amount of land resources and brings certain environmental problems such as groundwater, soil and environmental pollution.

[0004] Road engineering, especially highway engineering construction, has unique advantages in the large-scale consumption of industrial solid waste due to its large consumption of materials. Applying titanium gypsum to road engineering can realize the large-scale application of titanium gypsum, while alleviating the contradictions of land occupation and environmental pollution caused by the stacking of titanium gypsum, reducing the engineering construction cost, and reducing the use of natural fill and sand and gravel materials. However, due to the limitations of the physical and chemical properties of titanium gypsum itself, it is easy to absorb water and expand during long-term use, resulting in cracking when applied to the roadbed; on the other hand, the water stability of titanium gypsum itself is insufficient, and it disintegrates when exposed to water, unable to form strength and difficult to meet the road use requirements; furthermore, affected by raw materials, titanium gypsum contains certain harmful ions, which can cause certain pollution to the surrounding soil and groundwater during long-term service. Therefore, when applied to engineering, titanium gypsum must be solidified.

[0005] At present, certain research has been carried out on the solidification of road-use titanium gypsum, but there are still the following problems to be solved. First, the current titanium gypsum curing agent has a complex composition and a wide variety of raw materials, resulting in the complication of the production process and difficulty in industrial preparation; furthermore, to meet the road-use performance of titanium gypsum, the current titanium gypsum curing agent has a large dosage, and the dosage of some products reaches 20% - 40% of the mass of titanium gypsum, resulting in an increase in the cost of titanium gypsum composite materials as road-use fillers, and the comprehensive utilization cost is even higher than that of traditional fillers; at the same time, due to the limitations of the material properties of the titanium gypsum curing agent, some products must be prepared into a separate solution for incorporation, which changes the traditional roadbed construction method and increases the complexity of the construction of titanium gypsum road-use composite materials, making it difficult to be widely applied in engineering on a large scale. Summary of the Invention

[0006] In order to solve the deficiencies of the prior art, the object of the present invention is to provide a titanium gypsum curing agent, a preparation method and an application thereof. Through the hydration hardening reaction of the curing agent, the water absorption and expansion rate of titanium gypsum are reduced, while the mechanical properties and water stability of titanium gypsum are enhanced, meeting the road performance requirements of titanium gypsum as a subgrade and base course filler, reducing the engineering cost, and simplifying the preparation of the curing agent and the construction process of titanium gypsum.

[0007] In order to achieve the above object, the technical solution of the present invention is as follows:

[0008] In the first aspect of the present invention, a titanium gypsum curing agent is provided. By weight, the raw materials include: 30-50 parts of an activator, 10-15 parts of a filler, 30-50 parts of an active waste material, 1-10 parts of calcium oxide, and 2-5 parts of a dispersant;

[0009] The activator includes agent A and agent B with a mass ratio of 0.025-0.08; agent A includes sodium hydroxide and potassium hydroxide with a mass ratio of (0.6-1):(0-0.4); agent B includes ordinary Portland cement and composite Portland cement with a mass ratio of (0.7-1):(0-0.3).

[0010] In the second aspect of the present invention, a preparation method of the above titanium gypsum curing agent is provided, including the steps:

[0011] S11. Mix and grind the raw materials of agent A and agent B of the activator to obtain an activator powder;

[0012] S12. Grind the filler to obtain a filler powder;

[0013] S13. Mix the activator powder, the filler powder, the active waste powder, calcium oxide and the dispersant to obtain a titanium gypsum curing agent.

[0014] In the third aspect of the present invention, an application of the above titanium gypsum curing agent is provided, including an application in the preparation of a titanium gypsum subgrade. The titanium gypsum subgrade includes titanium gypsum and the above titanium gypsum curing agent, and the titanium gypsum curing agent accounts for 3-5% of the dry mass of titanium gypsum.

[0015] In the above application, the preparation method of the titanium gypsum subgrade includes the steps:

[0016] S21. After spreading titanium gypsum with a moisture content of 20-27%, spread the above titanium gypsum curing agent in a proportion of 3-5% of the dry mass of titanium gypsum;

[0017] S22. Mix and compact the titanium gypsum and the titanium gypsum curing agent;

[0018] S23. Keep it moist and cure for 3-4 days.

[0019] The beneficial effects of the present invention are as follows:

[0020] 1. The titanium gypsum curing agent provided by the present invention makes full use of the synergistic hydration and hardening effect among various solid waste raw materials. Through the double salt effect and the four-coordination isomerization effect of silicon among the solid waste raw materials, it can have a synergistic activation effect with titanium gypsum, form compounds or solid solutions with certain strength and stability, physically encapsulate the harmful substances in the titanium gypsum, effectively solidify the harmful substances in the titanium gypsum, and generate a certain road-using strength; the solid waste-based cementitious material particles reduce the porosity of titanium gypsum through the filling effect and the formation of more stable compounds or solid solutions, thereby restricting its volume expansion; the solid waste-based cementitious material physically compacts and fills, generates stable compounds, reduces pores, enhances integrity and interfacial bonding force, and hinders water penetration, thereby improving water stability, meeting the road-using performance requirements, and reducing the road-using cost; the raw materials of the curing agent are all common bulk solid waste materials and engineering materials, and only need to be mixed, homogenized and ground, and the preparation method is simple.

[0021] 2. The dosage of the titanium gypsum curing agent of the present invention is basically the same as that of the commonly used road stabilizers. Compared with the existing curing agent dosage, it is lower, and the total project cost can be significantly reduced compared with the traditional filled soil subgrade, and the economic advantage is obvious.

[0022] 3. The construction process of the titanium gypsum subgrade and base course of the present invention is the same as that of the traditional filled soil subgrade and base course construction process, and there is no need to transform the existing equipment, and the construction process is simple. Specific Embodiments

[0023] The present invention will be further described below in conjunction with the embodiments.

[0024] A titanium gypsum curing agent, comprising the following components in parts by mass: 30 - 50 parts of an activator, 10 - 15 parts of a filling material, 30 - 50 parts of an active solid waste material, 1 - 10 parts of calcium oxide, and 2 - 5 parts of a dispersant;

[0025] The activator comprises agent A and agent B with a mass ratio of (0.025 - 0.08):1; agent A comprises sodium hydroxide and potassium hydroxide with a mass ratio of (0.6 - 1):(0 - 0.4); agent B comprises ordinary Portland cement and composite Portland cement with a mass ratio of (0.7 - 1):(0 - 0.3).

[0026] Among the above components, Agent A of the activator can provide a strong alkaline environment, promote the breaking and recombination of silicon-oxygen bonds and aluminum-oxygen bonds in the active solid waste materials, form materials with hardening characteristics, and provide a certain strength; in Agent B, tricalcium aluminate will react with titanium gypsum to generate ettringite (AFt), and provide more hydration products, which are intertwined to form a network structure, wrapping the cementitious material particles and making the structure more dense; among them, ordinary Portland cement is the necessary activator, and composite Portland cement is the supplementary activator; in occasions where the requirements for strength and durability are relatively low, composite Portland cement can be used to control costs.

[0027] Optionally, the filling material includes waste glass powder and decarbonized coal gangue with a mass ratio of (0.4~1):(0~0.6). The filling material is used to fill the fine voids inside the titanium gypsum, improve the compactness, reduce the water absorption of the material, and improve the water stability.

[0028] Optionally, the specific surface area of the filling material is 500 m 2 / kg or more, so that it can fill into small-sized pores, and has a certain potential pozzolanic activity, improve the density, and thus reduce the water absorption and improve the water stability.

[0029] Optionally, the active solid waste materials include blast furnace slag, active steel slag and rice husk ash with a mass ratio of (0.5~1):(0~0.5):(0.5~0.8). The fineness of each active solid waste material is above 200 mesh; the blast furnace slag powder is of S95 grade or S105 grade; under alkaline conditions, sulfate ions (SO 4 ² - ) in the titanium gypsum react with calcium ions (Ca² + ) and aluminate in the alkali-activated material to generate ettringite (AFt); the hydration calcium silicate gel, calcium hydroxide and other products generated by the active solid waste materials under alkaline conditions are intertwined with the hydration products of titanium gypsum (such as hemihydrate gypsum) to form a dense network structure, achieving the effect of consuming the expansion components of titanium gypsum and generating hydraulicity at the same time, forming a certain strength, realizing the solidification of various components in titanium gypsum, and reducing the leaching of harmful substances; at the same time, it can also react with substances such as iron oxides in titanium gypsum to generate calcium ferrite aluminate hydrate, further improving the hydraulicity.

[0030] Optionally, the calcium oxide is a powder material with a fineness above 200 mesh, which is used to provide an alkaline environment, assist the activator to jointly activate the silicon-aluminum oxides in the active solid waste, break the chemical bonds therein, release active ions, promote the reaction between these ions, and form new chemical bonds and cementitious structures.

[0031] Optionally, the dispersant includes a mixture of polyvinyl alcohol powder material, triisopropanolamine, and calcium sulfate whiskers with a mass ratio of (0.2 to 1):(0.2 to 0.8):(0.5 to 1); the hydroxyl groups on the molecular chain of the polyvinyl alcohol powder material can form hydrogen bonds with water molecules, thereby enhancing hydrophilicity and water solubility, enabling the raw materials of the titanium gypsum curing agent to react fully, and further enhancing the curing effect of titanium gypsum; the triisopropanolamine can accelerate the formation of hydration products, thereby increasing the strength of titanium gypsum; the calcium sulfate whiskers can act as a skeleton in titanium gypsum like fibers, effectively transmitting stress, preventing crack propagation in titanium gypsum, and effectively curing titanium gypsum.

[0032] The preparation method of the above-mentioned titanium gypsum curing agent includes the steps:

[0033] S11. Mix and grind the raw materials of agent A and agent B of the activator to obtain activator powder;

[0034] S12. Grind the filling material to obtain filling powder;

[0035] S13. Mix the activator powder, filling powder, active solid waste powder, calcium oxide, and dispersant to obtain the titanium gypsum curing agent.

[0036] In the above steps, in step S11, the chemical activator A and the mineral phase activator B are fully mixed to provide a strong alkaline environment for the active solid waste material; in step S12, the potentially active filling material is fully ground to make it have a larger specific surface area, which is beneficial to exerting the filling effect and potential pozzolanic activity; the purpose of mixing in step S13 is to prevent the organic chemical substances in the dispersant from being damaged and losing their activity due to the external grinding force.

[0037] Optionally, the grinding method in S11 is ball milling at a speed of 120 to 140 rpm for 3 to 5 minutes, passing through a 200-mesh sieve, and the dispersion uniformity of the material is above 99%; the grinding method in S12 is ball milling for not less than 5 minutes until the specific surface area is above 500 m 2 / kg; in S13, the mixing time of each material in the high-efficiency powder mixer is not less than 4 minutes.

[0038] The prepared titanium gypsum curing agent can be applied to a titanium gypsum roadbed.

[0039] The above application of the titanium gypsum curing agent includes its application in the preparation of a titanium gypsum roadbed. The titanium gypsum roadbed includes titanium gypsum and the above-mentioned titanium gypsum curing agent, and the titanium gypsum curing agent accounts for 3 to 5% of the dry mass of titanium gypsum.

[0040] In the above application, the preparation method of the titanium gypsum roadbed includes the steps:

[0041] S21. After spreading the titanium gypsum with a moisture content of 20 - 27%, spread the above-mentioned titanium gypsum curing agent in a proportion of 3 - 5% of the dry mass of the titanium gypsum.

[0042] S22. Mix the titanium gypsum and the titanium gypsum curing agent and then compact them.

[0043] S23. Keep it moist and cure for 3 - 4 days.

[0044] In the above process, after the titanium gypsum with a set water content is mixed with the titanium gypsum curing agent, the water contained in the titanium gypsum itself participates in the reaction to achieve hydraulicity and gradually stabilizes during the subsequent reaction process, forming a dense roadbed.

[0045] Optionally, in S22, use a road mixer to mix the titanium gypsum and the titanium gypsum curing agent evenly. After the bulldozer compacts it 2 - 3 times, level it with a grader, and then use a roller to compact it to the set compaction degree, which is the same as the conventional roadbed construction method.

[0046] Optionally, in S23, cover it with geotextile and sprinkle water for curing. Keep the surface of the geotextile moist during the period to ensure the stability of the curing process and avoid defects such as cracking.

[0047] In the following examples and comparative examples, the source of the titanium gypsum is the same, and the physical properties and chemical compositions are consistent.

[0048] Example 1

[0049] A titanium gypsum curing agent, comprising the following components in parts by mass: 40 parts of an activator, 12 parts of a filler, 40 parts of an active solid waste material, 5 parts of calcium oxide, and 2 parts of a dispersant;

[0050] The activator includes agent A and agent B with a mass ratio of 0.05; agent A is sodium hydroxide, and agent B is P•O 42.5 ordinary Portland cement.

[0051] The filler is waste glass powder, and the specific surface area of the filler is 620m 2 / kg.

[0052] The active solid waste material includes blast furnace slag, active steel slag, and rice husk ash with a mass ratio of 0.5:0.2:0.8; the blast furnace slag powder is of S95 grade.

[0053] The calcium oxide is a powder material with a fineness of more than 200 meshes.

[0054] The dispersant is a powder material of polyvinyl alcohol, triisopropanolamine, and calcium sulfate whiskers with a mass ratio of 0.2:0.2:0.5.

[0055] The preparation method of the titanium gypsum curing agent in this example includes the steps:

[0056] S11. Put agent A and agent B of the activator into a ball mill according to the set mass ratio and grind for 3 min. The rotational speed of the ball mill is 120 rpm, and the dispersion uniformity of the mixture is 99.5% to obtain the initial mixture of the activator.

[0057] S12. Grind the filling material for 5 min to make the specific surface area of the obtained ultra-fine filling material be 620 m 2 / kg.

[0058] S13. Load the initial mixture of the activator, ultra-fine filling material, active solid waste powder, calcium oxide and dispersant into a high-efficiency powder mixer according to the set ratio and mix for 4 min to form a titanium gypsum curing agent.

[0059] Mix the titanium gypsum curing agent in this example with titanium gypsum (the titanium gypsum curing agent is 3% of the dry mass of titanium gypsum) to prepare laboratory specimens, including: 50 mm × 50 mm cylindrical specimens, which are cured under standard curing conditions, and the unconfined compressive strength of the laboratory is tested at 3 d and 7 d; prepare 200 mm × 50 mm × 50 mm cuboid specimens and cure them under standard curing conditions to test the dry shrinkage strain; test the stable immersion expansion rate of 120 mm × 120 mm cylindrical specimens.

[0060] Mix the titanium gypsum curing agent in this example with titanium gypsum (the titanium gypsum curing agent is 3% of the dry mass of titanium gypsum), and conduct a leaching toxicity determination test according to the "Determination Method for Leaching Toxicity of Solid Wastes" (GB / T 15555). The indicators measured in the leaching toxicity test include heavy metal elements such as cadmium, mercury, arsenic, chromium, etc. and sulfides.

[0061] Mix the titanium gypsum curing agent obtained in this example with titanium gypsum to prepare a titanium gypsum roadbed, including the steps:

[0062] S21. Precipitate and pre-treat the pressure-filtered titanium gypsum to make the moisture content reach about 23% for standby; evenly spread the precipitated titanium gypsum at the construction site and evenly sprinkle the above titanium gypsum curing agent according to 3% of the dry mass of titanium gypsum;

[0063] S22. Use a road mixer to evenly mix the titanium gypsum and the titanium gypsum curing agent, roll 3 times with a crawler bulldozer, level with a grader, and roll with a vibratory roller until the compaction degree reaches 96% and above;

[0064] S23. Cover with geotextile and sprinkle water for curing for 3 and 7 days. Keep the surface of the geotextile moist during the curing period. After curing, take cores with a core drill with a diameter of 100 mm and cut them into cylindrical specimens of 100 mm × 100 mm as on-site specimens to test the on-site unconfined compressive strength.

[0065] Example 2

[0066] A titanium gypsum curing agent, the raw materials of which include, by weight, 50 parts of an activator, 15 parts of a filling material, 50 parts of an active solid waste material, 1 part of calcium oxide, and 2 parts of a dispersant.

[0067] The activator includes agent A and agent B with a mass ratio of 0.07, agent A is sodium hydroxide, and agent B is P•O42.5 ordinary silicate cement and P•C42.5 composite silicate cement with a mass ratio of 0.7:0.3.

[0068] The filling material is waste glass powder and decarbonized coal gangue, with a mass ratio of 1:0.3. The specific surface area of ​​the filling material is 600m 2 / kg.

[0069] The active solid waste materials are S95 blast furnace slag powder, steel slag powder and rice husk ash in a mass ratio of 0.5:0.5:0.8.

[0070] The fineness of calcium oxide is 200 mesh.

[0071] The dispersant is a polyvinyl alcohol powder material, triisopropanolamine and calcium sulfate whisker in a mass ratio of 1:0.8:0.5. The steps of the preparation method are the same as those in Example 1, except that:

[0072] In S12, the specific surface area of ​​the ultrafine filler material obtained is 500m 2 / kg.

[0073] The titanium gypsum curing agent in this example was mixed with titanium gypsum (the titanium gypsum curing agent was 4% of the dry mass of titanium gypsum), and the same laboratory specimens as in Example 1 were prepared and tested, and a leaching toxicity determination test was performed.

[0074] The titanium gypsum curing agent obtained in this example was mixed with titanium gypsum to prepare a titanium gypsum roadbed and a field test piece was taken. The method was the same as that in Example 1, except that:

[0075] In S21, the titanium gypsum curing agent is evenly spread according to 4% of the dry mass of the titanium gypsum.

[0076] Example 3

[0077] A titanium gypsum curing agent, the raw materials of which are measured by weight: 45 parts of an activator, 12 parts of a filling material, 45 parts of an active solid waste material, 10 parts of calcium oxide, and 5 parts of a dispersant.

[0078] The activator includes agent A and agent B with a mass ratio of 0.08, agent A is a mixture of sodium hydroxide and potassium hydroxide with a mass ratio of 0.6:0.4, and agent B is a mixture of P•O42.5 ordinary silicate cement and P•C42.5 composite silicate cement with a mass ratio of 0.9:0.1.

[0079] The filling material is waste glass powder and decarbonized coal gangue, and their mass ratio is 0.5:0.6. The specific surface area of the filling material is 550 m 2 / kg.

[0080] The active solid waste material is S105 blast furnace slag powder, steel slag powder and rice husk ash with a mass ratio of 1:0.5:0.8.

[0081] The fineness of calcium oxide is 200 mesh.

[0082] The dispersant is a polyvinyl alcohol powder material, triisopropanolamine and calcium sulfate whiskers with a mass ratio of 0.5:0.6:0.8.

[0083] The steps of the preparation method are the same as those in Example 1, except that:

[0084] In S12, the specific surface area of the obtained ultra-fine filling material is 680 m 2 / kg.

[0085] Mix the titanium gypsum curing agent in this example with titanium gypsum (the titanium gypsum curing agent is 5% of the dry mass of titanium gypsum), prepare the same laboratory specimens as in Example 1 for testing, and conduct leaching toxicity determination tests.

[0086] Mix the titanium gypsum curing agent obtained in this example with titanium gypsum to prepare a titanium gypsum roadbed and take on-site specimens. The preparation method is the same as that in Example 1, except that:

[0087] In S21, sprinkle the above-mentioned titanium gypsum curing agent evenly according to 5% of the dry mass of titanium gypsum.

[0088] Comparative Example 1

[0089] This comparative example is titanium gypsum from the same source as in Example 1, without adding a titanium gypsum curing agent.

[0090] The laboratory specimens are in accordance with the dimensions of Example 1, and are prepared into 50 mm×50 mm cylindrical test blocks using titanium gypsum with a water content of about 23%, cured under standard curing conditions, and the unconfined compressive strength of the laboratory is tested at 3 d and 7 d; prepare 200 mm×50 mm×50 mm cuboid test blocks and cure them under standard curing conditions to test the dry shrinkage strain; test the stable immersion expansion rate of 120 mm×120 mm cylindrical test blocks; and conduct leaching toxicity determination tests.

[0091] The method for preparing the titanium gypsum roadbed includes:

[0092] The titanium gypsum after being precipitated to a water content of about 23% is evenly spread at the construction site; a road mixer is used to mix and crush the titanium gypsum, a crawler bulldozer is used to roll it 3 times, a grader is used to level it, and a vibratory roller is used to roll it to the design compaction degree; geotextile is covered and water curing is carried out for 3 and 7 days. During the curing period, the surface of the geotextile is kept moist. After curing, a core sampler with a diameter of 100 mm is used to take cores, and cylindrical specimens with dimensions of 100 mm×100 mm are cut to test the unconfined compressive strength in-situ for the in-situ specimens.

[0093] Comparative Example 2

[0094] In this comparative example, P•O42.5 ordinary Portland cement is used as the titanium gypsum curing agent. 5% of the dry mass of P•O42.5 ordinary Portland cement is mixed with titanium gypsum to prepare laboratory specimens, including: preparing 50 mm×50 mm cylindrical specimens, curing them under standard curing conditions, and testing the unconfined compressive strength in the laboratory at 3 d and 7 d; preparing 200 mm×50 mm×50 mm rectangular specimens and curing them under standard curing conditions to test the dry shrinkage strain; testing the stable immersion expansion rate of 120 mm×120 mm cylindrical specimens; and conducting leaching toxicity determination tests.

[0095] The method for preparing the titanium gypsum subgrade and taking in-situ specimens is the same as that in Example 1.

[0096] The performances of the laboratory specimens and in-situ specimens obtained in Example 1, Example 2, Example 3, Comparative Example 1 and Comparative Example 2 are shown in Table 1.

[0097] Table 1 Test results of laboratory specimens and in-situ specimens

[0098]

[0099] As can be seen from Table 1, compared with Comparative Example 1 and Comparative Example 2, the unconfined compressive strength of the titanium gypsum stabilized by the curing agent in the laboratory and in-situ tests at 3 d and 7 d has a relatively high increase. This shows that the multi-source solid waste has a synergistic hydration and hardening effect, and the multi-source solid waste curing agent is suitable for the solidification of titanium gypsum. Through the double salt effect and the isomorphic effect of silicon in tetracoordination among the various solid waste raw materials, a synergistic activation effect can occur with titanium gypsum, stimulating the active SiO 2 and active Al 2 O 3Generate C-S-H and C-A-H gels, and can also react with C-A-H to form ettringite, forming compounds or solid solutions with certain strength and stability, physically encapsulating the harmful substances in the titanium gypsum, achieving effective solidification of the harmful substances in the titanium gypsum, and generating a certain strength for road use. At the same time, compared with Comparative Example 1 and Comparative Example 2, the stable expansion rate and dry shrinkage rate of the titanium gypsum stabilized by the curing agent are both reduced. The waste-based cementitious material particles can effectively reduce the pore space in the titanium gypsum through their filling effect and promoting the formation of more stable compounds or solid solutions, thereby inhibiting the excessive expansion of its volume. In addition, these waste-based cementitious materials also reduce pores further by means of physical compaction and filling mechanisms, improving the overall structural strength of the material and the bonding ability between interfaces, effectively hindering the penetration of water, thereby improving the water stability of the material and ensuring that it meets the performance standards for road use.

[0100] According to the "Determination Method for Toxicity Characteristic Leaching Procedure of Solid Waste" (GB / T 15555), the leaching toxicity determination tests of the titanium gypsum stabilized by the curing agent were carried out on Example 1, Example 2, Example 3, Comparative Example 1 and Comparative Example 2 respectively. The measured indicators in the leaching toxicity test include heavy metal elements such as cadmium, mercury, arsenic, chromium and sulfide. The obtained results are shown in Table 2.

[0101] Table 2 Results of the leaching toxicity determination test

[0102]

[0103] As can be seen from Table 2: The measured indicators of the heavy metal leaching liquor toxicity determination test of the titanium gypsum stabilized by the curing agent in Example 1, Example 2 and Example 3 all meet the requirements of the maximum allowable discharge value of Class III in the "Groundwater Quality Standard" (GB / T 14848-2017) and can meet the limit requirements, while Comparative Example 1 and Comparative Example 2 do not meet the limit requirements, indicating that the present invention can achieve effective solidification of the harmful substances in the titanium gypsum.

[0104] The above are only the preferred embodiments of the present application and are not used to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A titanium gypsum curing agent, characterized in that: The raw materials include, by weight: 30-50 parts of an activator, 10-15 parts of a filler material, 30-50 parts of an active solid waste material, 1-10 parts of calcium oxide, and 2-5 parts of a dispersant; the activator includes an agent A and an agent B with a mass ratio of 0.025-0.08; the agent A includes sodium hydroxide and potassium hydroxide with a mass ratio of (0.6-1): (0-0.4); the agent B includes composite silicate cement and ordinary silicate cement with a mass ratio of (0.7-1): (0-0.3); The filling material includes waste glass powder and decarbonized coal gangue in a mass ratio of (0.4-1): (0-0.6); The active solid waste materials include blast furnace slag, active steel slag and rice husk ash in a mass ratio of (0.5-1): (0-0.5): (0.5-0.8); The dispersant comprises a mixture of polyvinyl alcohol powder material, triisopropanolamine and calcium sulfate whiskers in a mass ratio of (0.2-1): (0.2-0.8): (0.5-1).

2. The titanium gypsum curing agent according to claim 1, characterized in that: The specific surface area of ​​the filler material is 500m 2 / kg and above.

3. A method for preparing the titanium gypsum curing agent according to any one of claims 1-2, characterized in that: Includes steps: S11, mixing and grinding the raw materials of the activator A and B to obtain activator powder; S12, grinding the filling material to obtain filling powder; S13, mixing the activator powder, the filler powder, the active solid waste powder, the calcium oxide and the dispersant to obtain the titanium gypsum curing agent.

4. The method for preparing the titanium gypsum curing agent according to claim 3, characterized in that: The grinding method in S11 is to pass through a 200-mesh screen, and the uniformity of the dispersion of the material is above 99%; the grinding method in S12 is ball milling to a specific surface area of ​​500m 2 / kg or more.

5. An application of the titanium gypsum curing agent as described in any one of claims 1-2, characterized in that: The invention comprises application in preparing titanium gypsum roadbed, wherein the titanium gypsum roadbed comprises titanium gypsum and the titanium gypsum curing agent, and the titanium gypsum curing agent accounts for 3-5% of the dry mass of the titanium gypsum.

6. The use of the titanium gypsum curing agent as claimed in claim 5, characterized in that: The preparation method of the titanium gypsum roadbed comprises the steps of: S21, after spreading titanium gypsum with a moisture content of 20-27%, spreading the titanium gypsum curing agent at a ratio of 3-5% of the dry mass of the titanium gypsum; S22, mixing the titanium gypsum and the titanium gypsum curing agent and compacting them; S23. Keep moist and healthy for 3 to 4 days.

7. The use of the titanium gypsum curing agent as claimed in claim 6, characterized in that: In S22, titanium gypsum and titanium gypsum curing agent are mixed evenly with a road mixer, rolled 2 to 3 times with a bulldozer, leveled with a leveler, and then compacted to a set compaction degree with a roller.

8. The use of the titanium gypsum curing agent as claimed in claim 6, characterized in that: In S23, the geotextile is covered and watered to maintain curing, and the surface of the geotextile is kept moist during the curing process.

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