Anti-crack thermal insulation mortar prepared from high-volume lithium slag and preparation method of anti-crack thermal insulation mortar

Abstract

The invention discloses an anti-crack thermal insulation mortar prepared by using large-dosage lithium slag and a preparation method thereof, and the preparation method comprises the following steps: mixing dried lithium slag and an additive, and grinding and activating to obtain pretreated lithium slag powder; preparing the pretreated lithium slag powder into mortar; the mortar comprises the following components in parts by weight: 25-40 parts of cement and 30-60 parts of pretreated lithium slag powder, 10 to 40 parts of sand; 0.1 to 2.0 parts of engineering fiber and 0.01 to 0.1 part of water reducing agent. According to the anti-cracking thermal insulation mortar prepared by the invention, the variety and the use amount of additives are reduced, the cost is low, the later strength is high, corrosion resistance is realized, mechanical construction can be realized, and the modernized construction level of the building industry is improved.

Description

Technical Field

[0001] The invention relates to a method for preparing crack-resistant thermal insulation mortar by utilizing a large amount of lithium slag. Background Art

[0002] As a byproduct of lithium salt mining, the emission of lithium slag increases year by year. At present, the amount of slag produced by lithium extraction from lithium mica in Yichun is very huge. The production of one ton of lithium carbonate will produce thirty tons of lithium slag. With the increase of lithium carbonate production in Yichun, the annual output of lithium slag is expected to reach 20 million tons per year. However, as an auxiliary cementitious material for building materials, the utilization rate of lithium slag is less than 10%. Therefore, a large amount of lithium slag is landfilled, leading to ecological and environmental problems and waste of natural resources. Exploring the utilization of lithium slag is conducive to the sustainable development of the lithium salt industry, saving natural resources and protecting the environment. The demand for concrete in the construction industry has led to a shortage of natural resources and a deterioration of the environment, which in turn has led to a demand for innovation in concrete technology.

[0003] The anti-cracking and thermal insulation mortars currently used generally achieve anti-cracking and thermal insulation effects through external means such as polymer modification, fiber reinforcement, air entraining agent and cement shrinkage reducer. Physical means such as particle grading of sand in the mortar can also help to form a uniform and dense mortar structure and improve the anti-cracking effect. While these means improve the thermal insulation effect of the mortar, they also lead to higher production process requirements and increase the production cost of the mortar. In the context of the elimination of new and old production capacity in the building materials field and the gradual reduction of the market size, the current high-cost anti-cracking and thermal insulation mortar needs to improve the formulation process to achieve cost reduction and efficiency improvement. Summary of the invention

[0004] The main purpose of the present invention is to provide a method for preparing crack-resistant thermal insulation mortar using a large amount of lithium slag, aiming to solve the above technical problems.

[0005] To achieve the above object, the present invention proposes a method for preparing crack-resistant thermal insulation mortar using a large amount of lithium slag, comprising:

[0006] The dried lithium slag and the additive are mixed and then ground and activated to obtain pretreated lithium slag powder;

[0007] Mixing the pretreated lithium slag powder into mortar;

[0008] The mortar comprises the following components: 25-40 parts of cement, 30-60 parts of pre-treated lithium slag powder, 10-40 parts of sand, 0.1-2.0 parts of engineering fiber, and 0.01-0.1 parts of water reducing agent.

[0009] In one embodiment, the moisture content of the dried lithium slag is less than or equal to 1%.

[0010] In one embodiment, the additive is one or more of sodium lignin sulfonate, potassium chloride, sodium chloride, sodium carbonate, potassium carbonate, calcium chloride, trisodium phosphate, sodium acetate, and triethanolamine.

[0011] In one embodiment, the amount of the additive added is 0.1% to 1% of the lithium slag.

[0012] In one embodiment, the grinding method is ball milling or vertical milling.

[0013] In one embodiment, the specific surface area of ​​the lithium slag is 450m 2 / kg~700m 2 / kg.

[0014] In one embodiment, the engineering fiber is one or more of polypropylene fiber, PVA fiber and glass fiber.

[0015] In one embodiment, the water reducer is at least one of polycarboxylate-based high-efficiency water reducer polycarboxylic acid, lignin sulfonate water reducer, sodium dodecyl sulfate, and naphthalene-based water reducer.

[0016] In addition, the present invention also provides a crack-resistant thermal insulation mortar, which is prepared by the above-mentioned method for preparing the crack-resistant thermal insulation mortar using a large amount of lithium slag.

[0017] In the technical scheme of the present invention, lithium slag is an irregular porous structure with high porosity. After early grinding, the specific surface area of ​​lithium slag increases, and the pores are exposed more. The admixture can react with sulfates, hydrates, etc. in the lithium slag to generate insoluble salts, which helps to improve the early hydration activity of lithium slag. After a large amount of admixture is added to the mortar, heat insulation is formed by high porosity to improve the thermal insulation effect of the mortar. The anti-cracking thermal insulation mortar prepared by the present invention reduces the type and amount of admixtures, has low cost, high strength in the later stage, is corrosion-resistant, and can be mechanized for construction, thereby improving the level of modernization of the construction industry. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0020] In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0021] Furthermore, the technical solutions between the various embodiments of the present invention may be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in the field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0022] The invention provides a method for preparing crack-resistant thermal insulation mortar by utilizing a large amount of lithium slag.

[0023] The method for preparing crack-resistant thermal insulation mortar using high-doped lithium slag provided in an embodiment of the present invention comprises:

[0024] The dried lithium slag and the additive are mixed and then ground and activated to obtain pretreated lithium slag powder;

[0025] Mixing the pretreated lithium slag powder into mortar;

[0026] The mortar comprises the following components: 25-40 parts of cement, 30-60 parts of pre-treated lithium slag powder, 10-40 parts of sand, 0.1-2.0 parts of engineering fiber, and 0.01-0.1 parts of water reducing agent.

[0027] Lithium slag is a solid waste that has been ball-milled and then calcined at high temperature. It has a porous structure, contains a large amount of SiO2 and Al2O3, and has certain volcanic ash activity and good micro-aggregate filling effect. Mechanical grinding can reduce the particle size and increase the specific surface area, which is conducive to the exposure of active substances and improves their hydration activity. In addition, when adding additives such as sodium lignin sulfonate, potassium chloride, sodium chloride, and calcium chloride for mixed grinding, when the mortar is excited by adding water, the additives can react with sulfates, hydrates, etc. in the lithium slag to form insoluble salts, which helps to improve the early hydration activity of the lithium slag;

[0028] During the hydration reaction, the hydration reaction of lithium slag mainly produces needle- and rod-shaped ettringite (AFt). The chemical reaction formula for producing AFt in the hydration process is CaO·Al2O3+3CaSO4·2H2O→3C3A·3CaSO4·32H2O, which effectively improves the crack resistance of the mortar and generates calcium silicate hydrate (CSH), providing a guarantee for the strength of the mortar.

[0029] Lithium slag has an irregular porous structure and high porosity. After the initial grinding, the specific surface area of ​​lithium slag increases and the exposed pores increase. When added to the mortar in large quantities, the high porosity forms heat insulation, which improves the thermal insulation effect of the mortar.

[0030] The premixed anti-cracking thermal insulation mortar prepared by the invention reduces the types and usage of admixtures, has low cost, high later strength, is corrosion-resistant, can be mechanized in various aspects, and improves the modernization level of the construction industry.

[0031] In one embodiment, the moisture content of the dried lithium slag is less than or equal to 1%.

[0032] In one embodiment, the additive is one or more of sodium lignin sulfonate, potassium chloride, sodium chloride, sodium carbonate, potassium carbonate, calcium chloride, trisodium phosphate, sodium acetate, and triethanolamine.

[0033] In one embodiment, the amount of the additive added is 0.1% to 1% of the lithium slag.

[0034] In one embodiment, the grinding method is ball milling or vertical milling.

[0035] In one embodiment, the specific surface area of ​​the lithium slag is 450m 2 / kg~700m 2 / kg.

[0036] In one embodiment, the engineering fiber is one or more of polypropylene fiber, PVA fiber and glass fiber.

[0037] In one embodiment, the water reducer is at least one of polycarboxylate-based high-efficiency water reducer polycarboxylic acid, lignin sulfonate water reducer, sodium dodecyl sulfate, and naphthalene-based water reducer.

[0038] In addition, the present invention also provides a crack-resistant thermal insulation mortar, which is prepared by the above-mentioned method for preparing the crack-resistant thermal insulation mortar using a large amount of lithium slag.

[0039] The present invention is explained below based on examples.

[0040] Example 1

[0041] The dried lithium slag and an additive (wherein the additive is triethanolamine) with a content of 0.25% of the lithium slag were ball-milled for 15 minutes to obtain pretreated lithium slag powder.

[0042] Weigh 30 parts of pre-treated lithium slag powder, 25 parts of cement, 20 parts of sand, 0.1 parts of polycarboxylate water reducer, and 1 part of PVA fiber according to weight. At normal temperature and pressure, put the above components into a mixer and mix them evenly to obtain anti-cracking thermal insulation mortar.

[0043] Example 2

[0044] The dried lithium slag and an additive (wherein the additive is sodium acetate) with a content of 0.5% of the lithium slag were ball-milled for 15 minutes to obtain pretreated lithium slag powder.

[0045] Weigh 40 parts of pre-treated lithium slag powder, 30 parts of cement, 30 parts of sand, 0.1 parts of lignin sulfonate water reducer, and 0.5 parts of PVA fiber according to weight. At normal temperature and pressure, put the above components into a mixer and mix them evenly to obtain anti-cracking thermal insulation mortar.

[0046] Example 3

[0047] The dried lithium slag and 0.75% of an additive (wherein the additive is sodium carbonate and triethanolamine, and the ratio of the additive and the ratio of the additive to the lithium slag is 2:1) are ball-milled for 15 minutes to obtain pretreated lithium slag powder.

[0048] Weigh 40 parts of pre-treated lithium slag powder, 40 parts of cement, 40 parts of sand, 0.1 parts of lignin sulfonate water reducer, and 1 part of PVA fiber according to weight. At normal temperature and pressure, put the above components into a mixer and mix them evenly to obtain anti-cracking thermal insulation mortar.

[0049] The performance of the anti-cracking thermal insulation mortar obtained in Examples 1-3 was tested, and the test results are shown in Table 1.

[0050] Example Water retention rate / % Coagulation time / h 2h consistency loss rate / % 28d shrinkage / % 28d compressive strength / MPa 1 94.3 5.0 15 0.09 36.7 2 95.7 5.25 13 0.05 35.1 3 96.4 5.0 13 0.6 35.9

[0051] Table 1

[0052] It can be seen from the table that the anti-cracking thermal insulation mortar of the present invention meets the requirements in various properties when a large amount of lithium slag is added. Therefore, the present invention achieves the purpose of preparing mortar by lithium slag. By preparing mortar by low-cost lithium slag, the production cost of mortar is not only reduced, but also the problem of lithium slag being difficult to recycle is solved, the utilization rate of lithium slag is improved, and the ecological environment is protected at the same time, and a large amount of lithium slag is prevented from being buried.

[0053] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification under the concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for preparing crack-resistant thermal insulation mortar using a large amount of lithium slag, characterized in that: The method for preparing crack-resistant thermal insulation mortar using a large amount of lithium slag comprises: The dried lithium slag and the additive are mixed and then ground and activated to obtain pretreated lithium slag powder; Mixing the pretreated lithium slag powder into mortar; The mortar comprises the following components: 25-40 parts of cement, 30-60 parts of pre-treated lithium slag powder, 10-40 parts of sand, 0.1-2.0 parts of engineering fiber, and 0.01-0.1 parts of water reducing agent.

2. The method for preparing crack-resistant thermal insulation mortar using high-doped lithium slag according to claim 1, characterized in that: The moisture content of the dried lithium slag is less than or equal to 1%.

3. The method for preparing crack-resistant thermal insulation mortar using high-doped lithium slag according to claim 1, characterized in that: The additive is one or more of sodium lignin sulfonate, potassium chloride, sodium chloride, sodium carbonate, potassium carbonate, calcium chloride, trisodium phosphate, sodium acetate, and triethanolamine.

4. The method for preparing crack-resistant thermal insulation mortar using high-doped lithium slag according to claim 1, characterized in that: The amount of the additive added is 0.1% to 1% of the lithium slag.

5. The method for preparing crack-resistant thermal insulation mortar using high-doped lithium slag according to claim 1, characterized in that: The grinding method is ball milling or vertical milling.

6. The method for preparing crack-resistant thermal insulation mortar using high-doped lithium slag according to claim 5, characterized in that: The specific surface area of ​​the lithium slag is 450m 2 / kg~700m 2 / kg.

7. The method for preparing crack-resistant thermal insulation mortar using high-doped lithium slag according to claim 1, characterized in that: The engineering fiber is one or more of polypropylene fiber, PVA fiber and glass fiber.

8. The method for preparing crack-resistant thermal insulation mortar using high-doped lithium slag according to claim 1, characterized in that: The water reducer is at least one of polycarboxylate-based high-efficiency water reducer, polycarboxylic acid, lignin sulfonate water reducer, sodium dodecyl sulfonate, and naphthalene-based water reducer.

9. A crack-resistant thermal insulation mortar, characterized in that: The anti-cracking thermal insulation mortar is prepared by the preparation method of anti-cracking thermal insulation mortar using a large amount of lithium slag as described in any one of claims 1-8.