KR-20260066350-A - Fluoride removal composition containing oyster shell and method for treating hydrofluoric acid wastewater using the same

Abstract

The present invention relates to a method for treating hydrofluoric acid wastewater using oyster shells, and more specifically, to a method for treating hydrofluoric acid wastewater that removes fluoride ions in the hydrofluoric acid wastewater and neutralizes the acidic pH by preparing oyster shells into powder and adding them to the hydrofluoric acid wastewater. In addition, by providing a fluorine removal composition comprising oyster shell powder according to the present invention, fluorine can be removed from hydrofluoric acid wastewater in an economical and eco-friendly manner while neutralizing the acidic pH of the wastewater, and thus can be utilized for industrial wastewater treatment and resource recycling.

Inventors

• 원성욱
• 강수빈
• 민병찬

Assignees

• 경상국립대학교산학협력단

Dates

Publication Date

20260512

Application Date

20241104

Claims (12)

1. A composition for removing fluoride containing oyster shell powder.
2. In paragraph 1, The above oyster shell powder is, A composition for removing fluoride, characterized by having a particle size of 600 μm to 1000 μm.
3. In paragraph 1, The above fluoride removal composition is, A composition for removing fluoride, characterized by having a fluoride removal efficiency of 80 to 100%.
4. Step of washing oyster shells; A step of immersing the washed oyster shells in a sodium hypochlorite (NaClO) solution; A step of washing and drying the above-mentioned oyster shells; A step of grinding the dried oyster shells to produce powder; and A method for preparing a fluorine removal composition, characterized by including the step of separating particles from the above-mentioned powder using a sieve.
5. In paragraph 4, The above immersion step is, A method for preparing a fluoride removal composition, characterized by immersing the washed oyster shells in a 0.5 to 1.5% sodium hypochlorite (NaClO) solution for 23 to 25 hours.
6. In paragraph 4, The above drying step is, A method for preparing a fluorine removal composition, characterized by drying the oyster shells washed by immersion at the above-mentioned immersion at a temperature of 55 to 65 ℃ for 23 to 25 hours.
7. In paragraph 4, The step of manufacturing the above powder is, A method for preparing a fluorine removal composition, characterized by grinding the dried oyster shells above at a rotational speed of 700 to 900 rpm using balls with a diameter of 4 to 6 μm to produce a powder.
8. In paragraph 4, The step of separating the above particles is, A method for preparing a fluoride removal composition, characterized by sieving the above oyster shell powder through a sieve with a size of 600 μm to 1000 μm.
9. A method for treating hydrofluoric acid wastewater characterized by including the step of introducing a fluorine removal composition prepared by the manufacturing method of claim 4 into hydrofluoric acid wastewater.
10. In Paragraph 9, The above oyster shell powder is, A method for treating hydrofluoric acid wastewater characterized by particles having a size of 600 μm to 1000 μm.
11. In Paragraph 9, The above hydrofluoric acid wastewater treatment method is, A method for treating hydrofluoric acid wastewater characterized by having a fluorine removal efficiency of 80 to 100% in the above hydrofluoric acid wastewater.
12. In Paragraph 11, The above hydrofluoric acid wastewater treatment method is, A method for treating hydrofluoric acid wastewater, characterized in that when the fluoride removal efficiency is 80 to 100%, the pH of the hydrofluoric acid wastewater is neutralized to 5 to 7.

Description

Fluoride removal composition containing oyster shell and method for treating hydrofluoric acid wastewater using the same The present invention relates to a method for treating hydrofluoric acid wastewater using oyster shells, and more specifically, to a method for treating hydrofluoric acid wastewater that removes fluoride ions in the hydrofluoric acid wastewater and neutralizes the acidic pH by preparing oyster shells into powder and adding them to the hydrofluoric acid wastewater. The emergence of the Fourth Industrial Revolution has stimulated demand for electronic devices and significantly accelerated the expansion of the semiconductor industry, making a significant contribution to the technological development of human society through substantial investment and expansion in this sector over the past 20 years. While the semiconductor industry has contributed to economic prosperity, the environmental impact related to wastewater generation during the semiconductor manufacturing process cannot be overlooked. In particular, the generation of high-concentration hydrofluoric acid wastewater during the etching process in semiconductor manufacturing poses a major environmental problem. Currently, the most widely used method for treating hydrofluoric acid wastewater is the precipitation method using liquid slaked lime. However, when liquid slaked lime is used to remove fluoride from hydrofluoric acid wastewater, it has the disadvantage of reduced reactivity and increased pH due to its low solubility. Consequently, a larger amount of lime must be injected to remove fluoride from the wastewater, resulting in the generation of a large amount of sludge and incurring additional treatment costs. Furthermore, in the case of wastewater containing low concentrations of hydrofluoric acid, the treatment time is prolonged and reaction efficiency is low, requiring the input of more than five times the equivalent amount of slaked lime, which presents a problem of low efficiency. Meanwhile, approximately 300,000 tons of oyster shells are generated annually in Korea; however, only a portion of these shells are reused, with a large amount being discarded. Composed primarily of calcium carbonate, oyster shells possess immense potential as an abundant source of calcium, leading to ongoing research on their utilization as desulfurization materials, soil conditioners, for heavy metal removal, landfill materials, construction materials, and fertilizers. However, methods involving heat treatment at high temperatures of 800 to 1,500°C to obtain calcium carbonate and calcium oxide from oyster shells have been disclosed. These methods generate large amounts of carbon dioxide gas during processing and consume excessive energy, resulting in high manufacturing costs and making practical application difficult. Therefore, there is a need to develop methods for the environmentally friendly and effective disposal and recycling of oyster shells. Based on the above background technology, the inventors have completed the present invention, which involves manufacturing oyster shells into powder without heat treatment and adding them to high-concentration hydrofluoric acid wastewater to remove fluorine and neutralize the acidity of the wastewater to improve the pH. Figure 1 illustrates a method for treating wastewater containing fluorine using oyster shell powder prepared according to an embodiment of the present invention. Figure 2 is a diagram showing the change in chemical bonding between oyster shell powder and fluorine prepared according to an embodiment of the present invention using FT-IR. Figure 3 is a diagram showing the mineralogical composition of the chemical bonding of oyster shell powder and fluorine prepared according to an embodiment of the present invention, analyzed using XRD. Figure 4 is an image showing the change in surface morphology of chemical bonding between oyster shell powder and fluorine prepared according to an embodiment of the present invention, analyzed using SEM. Figure 5 is a diagram analyzing the effect on fluorine removal efficiency according to particle size of oyster shell powder manufactured according to an embodiment of the present invention. Figure 6 is a diagram analyzing the effect of the powder and initial fluoride concentration of oyster shell powder prepared according to an embodiment of the present invention on the fluoride removal efficiency. The terms used in this specification will be briefly explained, and the invention will be described in detail. The terms used in this invention have been selected based on currently widely used general terms while considering their functions within the invention; however, these terms may vary depending on the intent of those skilled in the art, case law, the emergence of new technologies, etc. Therefore, the terms used in this invention should be defined not merely by their names, but based on their meanings and the overall context of the invention. When a part o