A method for preparing acid-activated cementitious material using industrial tin dross

Abstract

The application discloses a method for preparing acid-activated cementing material by using industrial tin residue, and particularly relates to the following steps: drying and ball-milling the industrial tin residue, and sieving to obtain tin residue powder; uniformly mixing the industrial tin residue powder and a substance containing hexavalent chromium, adding a sulfuric acid solution, stirring, pouring into a mold, demolding and curing to obtain the acid-activated cementing material, and realizing the purpose of sealing the heavy metal hexavalent chromium; the method can treat waste with waste, and has a good application prospect.

Description

Technical Field

[0001] This invention belongs to the field of solid waste secondary utilization technology, specifically relating to a method for preparing acid-activated cementitious materials using industrial tin slag. Background Technology

[0002] Tin dross is a type of industrial solid waste generated during the smelting, refining, and processing of tin. It primarily originates from high-temperature reduction smelting, electrolytic refining, and electronic soldering of tin ore. During tin smelting, tin ore reacts with coke and flux in a high-temperature furnace, reducing metallic tin. Gangue and impurities form slag, or smelting tin dross, which still contains a certain amount of residual tin and valuable metals such as copper, lead, zinc, and antimony. In the electrolytic refining stage, impurities in the anode plate cannot be completely dissolved and precipitate as anode mud or chloride slag. This type of refined tin dross is rich in rare and precious metals such as silver, indium, and bismuth, and has high recycling value. Furthermore, in industries such as electronics manufacturing, home appliances, and communication equipment, solder is widely used for component connections. Waste solder paste, solder slag, and scrap solder generated during the soldering process constitute another important source of tin dross, known as waste solder dross. Its main components are lead-free alloys such as tin-copper and tin-silver-copper, or traditional tin-lead alloys. If these tin dross residues are not properly treated, they not only waste resources but may also pose a pollution risk to the environment due to the leaching of heavy metals. Therefore, a scientific understanding of the formation mechanism and sources of tin dross residues is fundamental to achieving their efficient recycling and resource utilization, and is of great significance for promoting the development of a circular economy and the construction of ecological civilization.

[0003] In recent years, rapid industrial development, while driving economic growth and technological progress, has also had a profound impact on the environment. Large-scale resource extraction, energy consumption, and production emissions have exacerbated air, water, and soil pollution, increased greenhouse gas emissions, and accelerated global climate change. Among these, heavy metal pollution, one of the more serious pollutants generated during industrial processes, cannot be ignored and can cause significant pollution to the surrounding environment, soil, and water. Hexavalent chromium is a highly hazardous heavy metal pollutant. It is highly toxic, and when ingested, it can cause serious damage to multiple systems in the human body. Hexavalent chromium can damage the respiratory system; long-term inhalation of hexavalent chromium compounds may lead to nasal septum perforation, respiratory irritation, and even lung cancer. It can also cause serious skin damage; skin contact with hexavalent chromium may cause allergic reactions such as redness, itching, and rashes, and long-term exposure may even lead to skin cancer. Furthermore, once hexavalent chromium enters the bloodstream, it has a toxic effect on the blood system, interfering with normal hematopoietic function and leading to anemia and other problems. Hexavalent chromium can also damage vital organs such as the liver and kidneys, interfering with their normal function and potentially leading to organ failure. Hexavalent chromium pollution is also extremely serious in the environment. It pollutes soil and water, affects plant growth, causing symptoms such as stunted growth, leaf discoloration, and wilting. It can also harm animals in the ecosystem through bioaccumulation in the food chain and may ultimately enter the human body through the food chain, further threatening human health. Therefore, it is essential to strictly control hexavalent chromium emissions and strengthen the treatment of hexavalent chromium pollution to protect human health and the ecological environment. Summary of the Invention

[0004] This invention provides a method for preparing acid-activated cementitious materials using industrial tin slag, the purpose of which is to solidify the heavy metal hexavalent chromium.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: 1. Dry the industrial tin dross, mechanically ball mill it, and then sieve it to obtain industrial tin dross powder; 2. Quickly mix the industrial tin dross powder and the hexavalent chromium-containing substance in a stainless steel basin, then pour in a 10-20% sulfuric acid solution and stir until homogeneous. Pour the mixture into a mold to form the product. The mass ratio of the hexavalent chromium-containing substance to the industrial tin dross powder is 1-5:100. 3. After the acid-activated gelling material has solidified, remove it from the mold and place it in a 45℃ oven for constant temperature curing. 4. After reaching the curing age (3 days), acid-activated gelling material is obtained, and the purpose of solidifying and sealing the heavy metal hexavalent chromium is achieved.

[0006] The present invention has the following advantages over the prior art: This invention uses industrial solid waste tin slag as raw material, adds an appropriate amount of acid to dissolve the iron in it and reacts with heavy metals in an oxidation-reduction reaction; this cementitious material has a good solidification effect on heavy metal chromium, thereby achieving the purpose of treating waste with waste and has good application prospects. Attached Figure Description

[0007] Figure 1 XRD pattern of industrial tin dross; Figure 2 The image shows the XRD pattern of the cementitious material prepared in Example 5 of this invention. Detailed Implementation

[0008] The present invention will be further described in detail below with reference to examples and accompanying drawings, but the protection of the present invention is not limited to the content described herein; The main components of the industrial tin slag used in the following examples are Fe2O3 51.6%, CaO 10.3%, Al2O3 6.8%, MgO 2.25%, and SiO2 16.9%. Example 1: A method for preparing acid-activated cementitious materials using industrial tin dross and its application in solidifying Cr(VI). (1) Industrial tin dross was placed in an electric oven and dried at a constant temperature of 80℃ for 24 h. After ball milling for 1.5 h, it was passed through a 120-mesh sieve to obtain industrial tin dross powder. The XRD pattern of industrial tin dross is shown in the figure. Figure 1 ; (2) Mix 0.6g K2CrO4 and 59.4g industrial tin slag powder in a mortar and stir quickly. Then pour in 27mL of 15% H2SO4 solution and stir for 3-5min. Pour into a 20mm×20mm×20mm six-piece mold. After the cementitious material solidifies, remove the mold and transfer it to a 45℃ oven for constant temperature curing. (3) After the cementitious material is cured for 72 hours, the cementitious material is obtained; The prepared gelling material was subjected to compressive strength and toxicity leaching tests. Specifically, the cured body was placed on a YAW-100P pressure testing machine, and the compressive strength was measured to be 11.3 MPa. Subsequently, the cured body was ground into powder in a mortar for toxicity leaching testing using the horizontal shaking method. 2g of the powder was placed in a PET plastic bottle, and 20 mL of deionized water was added according to a liquid-to-solid ratio of 10:1. The bottle was then placed in a horizontal shaking device, and the shaking frequency was adjusted to 120 times / min. After shaking for 8 hours, the mixture was allowed to stand for 16 hours. The filtrate was then used for Cr(VI) and total chromium concentration analysis. No Cr(VI) was detected using ultraviolet spectrophotometry. The total chromium concentration measured by ICP-OES was 0.066 mg / L, far below the national standard of 15 mg / L, indicating that the gelling material achieved a chromium fixation rate of over 99%.

[0009] Example 2: Method for preparing acid-activated cementitious materials using industrial tin dross and its application in solidifying Cr(VI). (1) The industrial tin dross was placed in an electric oven and dried at a constant temperature of 80°C for 24 h. After ball milling for 1.5 h, it was passed through a 120-mesh sieve to obtain industrial tin dross powder. (2) Mix 1.2g K2CrO4 and 58.8g industrial tin slag powder in a mortar and stir quickly. Then pour in 27mL of 15% H2SO4 solution and stir for 3-5min. Pour into a 20mm×20mm×20mm six-piece mold. After the cementitious material solidifies, remove the mold and transfer it to a 45℃ oven for constant temperature curing. (3) After the cementitious material is cured for 72 hours, the cementitious material is obtained; The prepared gelling material was subjected to compressive strength and toxicity leaching tests. Specifically, the cured body was placed on a YAW-100P pressure testing machine, and the compressive strength was measured to be 10.5 MPa. Subsequently, the cured body was ground into powder in a mortar for toxicity leaching testing using the horizontal shaking method. 2 g of the powder was placed in a PET plastic bottle, and 20 mL of deionized water was added according to a liquid-to-solid ratio of 10:1. The bottle was then placed in a horizontal shaking device, and the shaking frequency was adjusted to 120 times / min. After shaking for 8 hours, the mixture was allowed to stand for 16 hours. The filtrate was then used for Cr(VI) and total chromium concentration analysis. No Cr(VI) was detected using ultraviolet spectrophotometry. The total chromium concentration measured by ICP-OES was 0.071 mg / L, far below the national standard of 15 mg / L, indicating that the gelling material achieved a chromium fixation rate of over 99%.

[0010] Example 3: A method for preparing acid-activated cementitious materials using industrial tin dross and its application in solidifying Cr(VI). (1) The industrial tin dross was placed in an electric oven and dried at a constant temperature of 80°C for 24 h. After ball milling for 1.5 h, it was passed through a 120-mesh sieve to obtain industrial tin dross powder. (2) Mix 1.8g K2CrO4 and 58.2g industrial tin slag powder in a mortar and stir quickly. Then pour in 27mL of 15% H2SO4 solution and stir for 3-5min. Pour into a 20mm×20mm×20mm six-piece mold. After the cementitious material solidifies, remove the mold and transfer it to a 45℃ oven for constant temperature curing. (3) After the cementitious material is cured for 72 hours, the cementitious material is obtained; The prepared gelling material was subjected to compressive strength and toxicity leaching tests. Specifically, the cured body was placed on a YAW-100P pressure testing machine, and the compressive strength was measured to be 14.2 MPa. Subsequently, the cured body was ground into powder in a mortar for toxicity leaching testing using the horizontal shaking method. 2g of the powder was placed in a PET plastic bottle, and 20mL of deionized water was added according to a liquid-to-solid ratio of 10:1. The bottle was then placed in a horizontal shaking device, and the shaking frequency was adjusted to 120 times / min. After shaking for 8 hours, the mixture was allowed to stand for 16 hours. The filtrate was then used for Cr(VI) and total chromium concentration analysis. No Cr(VI) was detected using ultraviolet spectrophotometry. The total chromium concentration measured by ICP-OES was 0.08 mg / L, far below the national standard of 15 mg / L, indicating that the gelling material achieved a chromium fixation rate of over 99%.

[0011] Example 4: A method for preparing acid-activated cementitious materials using industrial tin dross and its application in solidifying Cr(VI). (1) The industrial tin dross was placed in an electric oven and dried at a constant temperature of 80°C for 24 h. After ball milling for 1.5 h, it was passed through a 120-mesh sieve to obtain industrial tin dross powder. (2) Mix 2.4g K2CrO4 and 57.6g industrial tin slag powder in a mortar and stir quickly. Then pour in 27mL of 15% H2SO4 solution and stir for 3-5 minutes. Pour into a 20mm×20mm×20mm six-piece mold. After the cementitious material solidifies, remove the mold and transfer it to a 45℃ oven for constant temperature curing. (3) After the cementitious material is cured for 72 hours, the cementitious material is obtained; The prepared gelling material was subjected to compressive strength and toxicity leaching tests. Specifically, the cured body was placed on a YAW-100P pressure testing machine, and the compressive strength was measured to be 17.1 MPa. Subsequently, the cured body was ground into powder in a mortar for toxicity leaching testing using the horizontal shaking method. 2g of the powder was placed in a PET plastic bottle, and 20 mL of deionized water was added according to a liquid-to-solid ratio of 10:1. The bottle was then placed in a horizontal shaking device, and the shaking frequency was adjusted to 120 times / min. After shaking for 8 hours, the mixture was allowed to stand for 16 hours. The filtrate was then used for Cr(VI) and total chromium concentration analysis. No Cr(VI) was detected using ultraviolet spectrophotometry. The total chromium concentration measured by ICP-OES was 0.065 mg / L, far below the national standard of 15 mg / L, indicating that the gelling material achieved a chromium fixation rate of over 99%.

[0012] Example 5: A method for preparing acid-activated cementitious materials using industrial tin dross and its application in solidifying Cr(VI). (1) The industrial tin dross was placed in an electric oven and dried at a constant temperature of 80°C for 24 h. After ball milling for 1.5 h, it was passed through a 120-mesh sieve to obtain industrial tin dross powder. (2) Mix 3g K2CrO4 and 57g industrial tin slag powder in a mortar and stir quickly. Then pour in 27 mL of 15% H2SO4 solution and stir for 3-5 min. Pour into a 20mm×20mm×20mm six-piece mold. After the cementitious material solidifies, remove the mold and transfer it to a 45℃ oven for constant temperature curing. (3) After curing the cementitious material for 72 hours, the cementitious material was obtained. The XRD pattern of the cementitious material is shown in the figure below. Figure 2 As shown; The prepared gelling material was subjected to compressive strength and toxicity leaching tests. Specifically, the cured body was placed on a YAW-100P pressure testing machine, and the compressive strength was measured to be 2.4 MPa. Subsequently, the cured body was ground into powder in a mortar for toxicity leaching testing using the horizontal shaking method. 2 g of the powder was placed in a PET plastic bottle, and 20 mL of deionized water was added according to a liquid-to-solid ratio of 10:1. The bottle was then placed in a horizontal shaking device, and the shaking frequency was adjusted to 120 times / min. After shaking for 8 hours, the mixture was allowed to stand for 16 hours. The filtrate was then used for Cr(VI) and total chromium concentration analysis. No Cr(VI) was detected using ultraviolet spectrophotometry. The total chromium concentration measured by ICP-OES was 0.06 mg / L, far below the national standard of 15 mg / L, indicating that the gelling material achieved a chromium fixation rate of over 99%.

[0013] This invention uses industrial solid waste tin slag as raw material, adds an appropriate amount of acid to dissolve the iron in it and reacts with heavy metals in an oxidation-reduction reaction; this cementitious material has a good solidification effect on heavy metal chromium.

Claims

1. A method for preparing acid-activated cementitious materials using industrial tin slag, characterized in that: Industrial tin dross is dried, ball-milled, and sieved to obtain tin dross powder. The industrial tin dross powder and hexavalent chromium-containing substances are mixed evenly, sulfuric acid solution is added, stirred, poured into a mold to form, demolded and cured to obtain acid-activated gelling material, which achieves the purpose of solidifying the heavy metal hexavalent chromium.

2. The method for preparing acid-activated cementitious materials using industrial tin slag according to claim 1, characterized in that: The hexavalent chromium-containing substance is either a hexavalent chromium-containing reagent or a hexavalent chromium-containing pollutant. The mass ratio of the hexavalent chromium-containing substance to industrial tin slag powder is 1-5:

100.

3. The method for preparing acid-activated cementitious materials using industrial tin slag according to claim 1, characterized in that: The mass concentration of the sulfuric acid solution is 10-20%.

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