Artificially sintered calcium fluoride auxiliary material, preparation method and application

Abstract

The present invention provides an artificially sintered calcium fluoride auxiliary material, a preparation method and an application, and belongs to the field of waste regeneration technology. The present invention first mixes waste slag with waste acid to convert calcium oxide in the waste slag sludge into calcium fluoride; then adds part of the aluminum ions in the adsorption system of bio-based adsorption materials; then adds waste alkali solution to further flocculate the aluminum ions, and adds surfactant aeration flotation to further reduce the content of aluminum ions and other elements in the system; finally, after dehydration and drying and high-temperature sintering, an artificially sintered calcium fluoride auxiliary material is obtained. The present invention successfully converts the waste sludge of the photovoltaic manufacturing industry into a calcium fluoride auxiliary material by using a variety of process means, realizing the efficient secondary recycling of industrial waste and waste acid. It effectively reduces the pressure of enterprise waste treatment and realizes the high-value secondary utilization of waste sludge. It provides a new idea of ​​green and environmentally friendly process for high-energy-consuming and high-emission industrial enterprises to treat waste.

Description

Technical Field

[0001] The invention relates to the technical field of waste regeneration, and in particular to an artificially sintered calcium fluoride auxiliary material, a preparation method and application thereof. Background Art

[0002] Calcium fluoride is widely used as a flux and desulfurizer in the steelmaking process. In the steelmaking process, calcium fluoride reduces the melting point of refractory materials, promotes slag flow, and separates slag and metal well, thereby enhancing the forgeability and tensile strength of the metal. This characteristic makes calcium fluoride an indispensable flux in the smelting process, and is widely used in steel smelting, ferroalloy production, ironmaking process and non-ferrous metal smelting. In addition, in the steelmaking process, molten iron often contains a large amount of sulfur. The addition of calcium fluoride can effectively remove sulfur from the molten iron, thereby improving the quality and purity of the steel. This is because calcium fluoride can react with sulfur in the molten iron to form calcium sulfide, thereby reducing the sulfur content, which is crucial for the production of high-quality steel. These applications of calcium fluoride not only improve smelting efficiency, but also promote the flow of metal and the separation of impurities, thereby improving the purity and quality of the product. Therefore, calcium fluoride plays a vital role in the metallurgical industry.

[0003] Fluorite is an important mineral, also known as fluorite, and is a common mineral. Fluorite is a fluorine-containing compound with strong fluoride ion activity, which can be widely used in metallurgy, chemical industry, building materials and other fields. In steelmaking production, fluorite is often used as a steelmaking flux to improve steelmaking efficiency and quality. As a steelmaking auxiliary material, its main function is to improve the efficiency and quality of steelmaking. The calcium fluoride component contained in fluorite can be used as a flux in the steelmaking furnace to stabilize and precipitate impurities and non-metallic substances in the slag, making the steelmaking process more stable and smooth. As a steelmaking flux, fluorite can promote the precipitation of impurities and non-metallic substances in the slag to prevent them from interfering with the steelmaking process. Specifically, fluorite can react with impurities and non-metallic substances in the slag in the form of fluoride to produce a precipitable fluoride precipitate, thereby stabilizing the impurities and non-metallic substances in the slag and controlling their content. In addition, fluorite can also reduce the steelmaking temperature and reduce the heat loss in the steelmaking process, thereby improving the efficiency of steelmaking. In the later stage of steelmaking, fluorite can also react with impurities in the residual slag, stabilize and precipitate it, thereby reducing waste and pollutants generated by steelmaking. When using fluorite as a steelmaking flux, attention should be paid to the stability of quality and the accuracy of the ratio to ensure its effect. At the same time, fluorite itself has a certain degree of corrosiveness, and attention should be paid to measures such as layered feeding and turning over during feeding to avoid corrosion of equipment such as furnace walls. As an important steelmaking auxiliary material, fluorite can improve steelmaking efficiency and quality and ensure the stability and smooth progress of the steelmaking process. Through the input of fluorite, steel mills can reduce production costs, improve processing efficiency, and promote the healthy development of the steel industry.

[0004] The photovoltaic industry produces a large amount of waste residue and waste liquid in the process of producing photovoltaic panels. At present, these waste residue and waste liquid can only be transferred to ordinary building materials manufacturers to make bricks and stones and other materials. The companies also need to pay a large amount of environmental protection funds, which also brings great problems to environmental protection. Converting these waste residues and waste liquids from the photovoltaic industry into useful industrial raw materials for secondary use has become an important technical issue with high social and economic benefits. Summary of the invention

[0005] In view of this, the present invention provides a method for preparing artificial sintered calcium fluoride auxiliary material, which converts waste sludge from the photovoltaic manufacturing industry into calcium fluoride auxiliary material, and realizes the efficient secondary recycling of industrial waste including sludge and waste acid. It effectively reduces the pressure of enterprise waste treatment and realizes the high-value secondary utilization of sludge waste. It provides a new idea of ​​green and environmentally friendly process for high-energy-consuming and high-emission industrial enterprises to treat waste.

[0006] The method for preparing an artificially sintered calcium fluoride auxiliary material of the present invention comprises the following steps:

[0007] (1) mixing the waste residue and the waste acid to obtain waste sludge, and stirring; this process converts calcium oxide in the waste residue sludge into calcium fluoride;

[0008] (2) adding a bio-based adsorption material to the waste sludge from step (1) for 20 to 120 minutes to adsorb part of the aluminum ions in the system, and then filtering to remove the bio-based adsorption material;

[0009] (3) adding waste alkali solution to the filtered waste sludge to adjust the pH value of the system to 6.5 to 7.5; this can further flocculate aluminum ions;

[0010] (4) adding a surfactant and stirring, then introducing air for aeration for 30-60 minutes, leaving the mixture to stand for a certain period of time, and then removing the upper foamy substance and liquid to obtain a muddy substance; this is to further reduce the content of aluminum ions and elements such as sulfur and phosphorus in the system;

[0011] (5) Dehydrating and drying the muddy substance, sintering at high temperature to obtain a sintered material, and then crushing the sintered material to obtain the artificially sintered calcium fluoride auxiliary material.

[0012] Preferably, the mass ratio of the waste residue to the waste acid in step (1) is 500:1 to 100:1.

[0013] Preferably, the waste residue in step (1) is waste mud residue from silicon wafer processing in the photovoltaic industry; the waste acid is acid waste liquid generated during the processing of photovoltaic and glass processing industries; the waste residue comprises the following raw materials in mass percentage: 5-50% calcium oxide, 5-70% calcium fluoride, 0.1-5% calcium sulfate, and the remainder is unavoidable impurities; the main component of the waste acid is at least one of hydrofluoric acid, nitric acid, and hydrochloric acid; the acid content in the waste acid is 5-50m / v%.

[0014] Preferably, the bio-based adsorption material in step (2) is at least one of activated carbon and biochar; and the diameter of the bio-based adsorption material is 3-5 cm.

[0015] Preferably, the mass ratio of the bio-based adsorption material to the waste sludge in step (2) is 1-2:200-500.

[0016] Preferably, the surfactant in step (4) is any one of polyethylene glycol ether, polyethylene glycol sulfate, polyoxyethylene ethyl ether, potassium chloride, and mannitol; and the mass ratio of the waste residue to the surfactant is 1000: 1 to 100000: 1. Adding the surfactant can transfer sulfur, phosphorus, etc. to the upper foam phase under ventilation conditions, thereby assisting flotation separation.

[0017] Preferably, the specific steps of drying in step (5) are: drying at 500-600° C. for 120-30 min.

[0018] Preferably, the specific steps of high temperature sintering in step (5) are: sintering at 1000-1100° C. for 1.5-2 hours.

[0019] Another object of the present invention is to provide an artificially sintered calcium fluoride auxiliary material prepared by the above method, wherein the calcium fluoride auxiliary material comprises the following components by weight: calcium fluoride ≥ 75%, calcium oxide 10-15%, silicon dioxide ≤ 8%, and the remainder is inevitable impurities. The impurities include sulfide, potassium chloride, sodium chloride, etc.

[0020] The artificially sintered calcium fluoride auxiliary material is used for steel smelting.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention successfully converts the waste sludge of the photovoltaic manufacturing industry into calcium fluoride auxiliary material by using a variety of process means, realizing the efficient secondary recycling of industrial waste and waste acid. It effectively reduces the pressure of waste treatment in enterprises and realizes the high-value secondary utilization of waste sludge. It provides a new green and environmentally friendly process for high-energy-consuming and high-emission industrial enterprises to treat waste, and provides a new slag additive for steelmaking blast furnaces. DETAILED DESCRIPTION

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

[0024] Example 1

[0025] A method for preparing an artificially sintered calcium fluoride auxiliary material, comprising the following steps:

[0026] (1) 50 kg of waste residue and 0.5 kg of industrial hydrofluoric acid waste liquid are mixed to obtain waste sludge, and the mixture is stirred; this process converts calcium oxide in the waste sludge into calcium fluoride;

[0027] (2) adding 0.25 kg of 3 cm block coal-based activated carbon adsorption material to 50.5 kg of waste sludge from step (1), mixing and stirring for 120 min; then filtering with a metal mesh to remove the bio-based adsorption material;

[0028] The preparation method of the coal-based activated carbon adsorption material is as follows: take coal-based activated carbon with a high oxygen content (Henan Songshan Technology Co., Ltd., coal-based granular air purification activated carbon, model SSCKP16) first through a sieve of 20-40 mesh, wash and soak with pure water for 24 hours, and dry in an oven for use. Place 1 kg of the dried coal-based activated carbon in a briquetting machine and briquette with a 3 cm diameter mold to obtain the corresponding block activated carbon material.

[0029] (3) adding waste alkali solution to the filtered waste sludge to adjust the pH value of the system to 7.2;

[0030] (4) adding 1 kg of surfactant aqueous solution (containing 20 g of surfactant PEG) and stirring, then introducing air for aeration for 40 minutes and then standing for 120 minutes, and then removing the upper foamy substance and liquid to obtain a muddy substance;

[0031] (5) Dehydrating and drying the muddy substance, sintering at high temperature to obtain a sintered material, and then crushing it to obtain the artificial sintered calcium fluoride auxiliary material; the specific step of drying is: drying at 350° C. for 25 minutes; the specific step of high-temperature sintering is: sintering at 1100° C. for 1.5 hours.

[0032] The finished product is a porous loose granular material with relatively uniform size, and the size is 3-5 cm.

[0033] The waste residue is the waste from silicon wafer processing in the photovoltaic industry (the remainder is impurities). The composition of the waste residue is shown in Table 1:

[0034] Table 1

[0035] Element Calcium Fluoride Calcium Oxide Calcium sulfate Sodium sulfide Calcium phosphate content 59.27％ 19.32％ 0.18％ 0.07％ 0.69％

[0036] The composition of the industrial hydrofluoric acid waste liquid (the balance is water and unavoidable impurities) is shown in Table 2:

[0037] Table 2

[0038] Element HF HCl <![CDATA[HNO 3 ]]> content 20.32％ 15.34％ 6.72％

[0039] The composition of the waste alkali solution (the balance is water and inevitable impurities) is shown in Table 3:

[0040] Table 3

[0041] Element NaOH KOH <![CDATA[NH 3 ·H 2 O]]> content 10.17m / v% 8.32m / v% 15.26m / v%

[0042] The composition content of the artificially sintered calcium fluoride auxiliary material prepared in Example 1 of the present invention is shown in Table 4:

[0043] Table 4

[0044] Element Calcium Fluoride Calcium Oxide Silicon dioxide Unavoidable impurities content 78.32％ 12.64％ 7.32％ margin

[0045] Example 2

[0046] A method for preparing an artificially sintered calcium fluoride auxiliary material, comprising the following steps:

[0047] (1) 50 kg of waste residue and 0.5 kg of industrial hydrofluoric acid waste liquid are mixed to obtain waste sludge, and the mixture is stirred; this process converts calcium oxide in the waste sludge into calcium fluoride;

[0048] (2) adding 0.25 kg of 3 cm block coal-based activated carbon adsorption material to 50.5 kg of waste sludge from step (1), mixing and stirring for 120 min; then filtering with a metal mesh to remove the bio-based adsorption material;

[0049] The preparation method of the coal-based activated carbon adsorption material is the same as that of Example 1;

[0050] (3) adding waste alkali solution to the filtered waste sludge to adjust the pH value of the system to 7.1;

[0051] (4) adding 1 kg of surfactant aqueous solution (containing 20 g of surfactant PEG) and stirring, then introducing air for aeration for 50 minutes and then standing for 120 minutes, and then removing the upper foamy substance and liquid to obtain a muddy substance;

[0052] (5) Dehydrating and drying the muddy substance, sintering at high temperature to obtain a sintered material, and then crushing it to obtain the artificial sintered calcium fluoride auxiliary material; the specific step of drying is: drying at 350° C. for 30 minutes; the specific step of high-temperature sintering is: sintering at 1050° C. for 1.5 hours.

[0053] The finished product is a porous loose granular material with relatively uniform size, and the size is 3-5 cm.

[0054] The components of the waste residue, industrial hydrofluoric acid waste liquid and waste alkali liquid are the same as those in Example 1.

[0055] The composition content of the artificially sintered calcium fluoride auxiliary material prepared in Example 2 of the present invention is shown in Table 5:

[0056] Table 5

[0057] Element Calcium Fluoride Calcium Oxide Silicon dioxide Unavoidable impurities content 80.47％ 11.39％ 7.65％ margin

[0058] The performance of the artificially sintered calcium fluoride auxiliary material prepared by the present invention was tested, and the results obtained were as follows:

[0059] The performance of the artificially sintered calcium fluoride auxiliary materials prepared in Example 1 and Example 2 was tested, and the results are shown in Table 6:

[0060] Table 6

[0061] Hardness (Fahrenheit) Moisture content (%) Example 1 6.7 0.2 Example 2 6.6 0.3

[0062] The invention adopts waste residues from silicon wafer processing in the photovoltaic industry and acid waste liquid generated in the processing of photovoltaic and glass processing industries as raw materials, adds waste alkali to prepare artificial sintered calcium fluoride auxiliary materials, and the prepared product has higher hardness, thereby improving the recovery and utilization rate of waste residues, waste acid and waste alkali.

[0063] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing an artificially sintered calcium fluoride auxiliary material, characterized in that: The following steps are involved: (1) Mixing the waste residue and the waste acid to obtain waste sludge, and stirring; (2) adding bio-based adsorption material to the waste sludge from step (1) for adsorption for 20 to 120 min, and then filtering to remove the bio-based adsorption material; (3) Add waste alkali solution to the filtered waste sludge to make the pH value of the system 6.5~7.5; (4) Add a surfactant and stir, then introduce air for aeration for 30-60 minutes, let stand for a certain period of time, and then remove the upper foamy substance and liquid to obtain a muddy substance; (5) dehydrating and drying the mud-like substance, sintering at high temperature to obtain a sintered material, and then crushing the sintered calcium fluoride auxiliary material to obtain the artificial sintered calcium fluoride auxiliary material; The waste residue in step (1) is waste mud residue from silicon wafer processing in the photovoltaic industry; the waste acid is acid waste liquid generated in the photovoltaic and glass processing industries; the waste residue comprises the following raw materials in mass percentage: 5-50% calcium oxide, 5-70% calcium fluoride, 0.1-5% calcium sulfate, and the remainder is unavoidable impurities; the main component of the waste acid is at least one of hydrofluoric acid, nitric acid, and hydrochloric acid; the acid content in the waste acid is 5-50m / v; The surfactant described in step (4) is polyethylene glycol ether; the mass ratio of the waste residue to the surfactant is 1000:1 to 100000:

1.

2. The method for preparing the artificially sintered calcium fluoride auxiliary material according to claim 1, characterized in that: The mass ratio of the waste residue to the waste acid in step (1) is 500:1 to 100:

1.

3. The method for preparing the artificially sintered calcium fluoride auxiliary material according to claim 1, characterized in that: The bio-based adsorption material in step (2) is at least one of activated carbon and biochar; the diameter of the bio-based adsorption material is 3-5 cm.

4. The method for preparing the artificially sintered calcium fluoride auxiliary material according to claim 1, characterized in that: The mass ratio of the bio-based adsorption material to the waste sludge in step (2) is 1-2:200-500.

5. The method for preparing the artificially sintered calcium fluoride auxiliary material according to claim 1, characterized in that: The specific steps of drying in step (5) are: drying at 350-600° C. for 20-120 min.

6. The method for preparing the artificially sintered calcium fluoride auxiliary material according to claim 1, characterized in that: The specific steps of high temperature sintering described in step (5) are: sintering at 1000-1100° C. for 1.5-2 hours.

7. An artificially sintered calcium fluoride auxiliary material, characterized in that: The method for preparing the artificially sintered calcium fluoride auxiliary material according to claim 1 comprises the following components in parts by weight: calcium fluoride ≥ 75%, calcium oxide 10-15%, silicon dioxide ≤ 8%, and the remainder being unavoidable impurities.

8. Use of the artificially sintered calcium fluoride auxiliary material according to claim 7, characterized in that: The artificially sintered calcium fluoride auxiliary material is used for steel smelting.