TW201436948A - Method for recycling scraped polishing powder - Google Patents

Abstract

A method for recycling scraped polishing powder includes (a) acquiring scraped polishing powder; (b) place the scraped polishing powder into an acid solution, whereby forming an immersion liquid; (c) leaching the immersion liquid; and (d) pouring an alkaline precipitation agent to form a mixed liquor, and purifying with precipitation process, whereby a first compound and a second compound containing rare earth element can be retrieved separately. Therefore, valuable metal like rare earth element can be isolated from the scraped polishing powder, thus achieving the objective of recycling.

Description

Waste polishing powder resource regeneration method

The invention and a resource regeneration method, especially a resource regeneration method of waste polishing powder, belong to the technical field of waste resource regeneration.

In recent decades, human science and technology have made breakthroughs, and rare earth elements have played an irreplaceable role in the development of many scientific and technological fields. For example, polishing powders are usually made of cerium oxide and cerium oxide. The composition of rare earth compounds, however, the hardness of different materials is not the same, the chemical properties in water are also different, so the use is also different, nowadays it has been widely used in various optical glass devices, optical lenses, Polishing process for flat glass, semiconductor wafers, and metal precision products; however, in the past, human beings have been eager for the natural environment, for the convenience of life, constantly consuming a large amount of natural resources, and due to the gradual exhaustion of many natural resources, The development and development of the country has begun to pay attention to the importance of sustainable development. Therefore, the concept of renewable resources has been constructed. With the continuous support of the domestic government, the recycling of rare earth elements from waste polishing powder has become a resource for the future. Thinking about recycling.

Therefore, it is desirable to recover rare earth oxides from polishing waste liquids containing rare earth elements, and it is a field of use of polishing materials mainly composed of rare earth oxide fine powders. However, the requirements for high precision of processed materials are continuously improved, and polishing materials should be used. With the quality and requirements, it is necessary to reduce the particle size and reduce the amount of foreign matter. However, it is difficult to obtain a polishing material for high-precision grinding processing by polishing waste liquid containing rare earth elements; therefore, foreign companies have developed the above-mentioned shortcomings such as Patent No. CN1456624 "Failure rare earth polishing powder" The method of regeneration, wherein the method used is subjected to high-temperature calcination heat treatment, which is relatively expensive in cost and requires a long wait, and is not practical in today's demanding efficiency in the commercial market. In addition, there is a special Kaiping 10- Japanese Patent Publication No. 280060, "A method of solid-liquid separation to recover rare earth elements after coagulation treatment of grinding waste liquid", however, the method for recovering the rare earth oxides is to add an organic aggregating agent to the liquid to be separated, thereby adding one It is necessary to pass the precise formulation of the fixed component of the organic agglutinating agent, and the experimental conditions and methods are cumbersome, and the economic value that can be exerted is limited.

Among them, the waste polishing powder contains rare earth metal elements of cerium (Ce) and lanthanum (La). If it can be separated from the waste polishing powder and the recovery rate and purity are improved, further resource recycling treatment can create an amazing economic opportunity. However, in the current domestic patent relating to waste polishing powder, no technology or method related to the recycling of waste polishing powder has been found.

In view of the above, the present invention provides a resource regeneration method for waste polishing powder, which is combined with a precipitation method by an impregnation and dissolution treatment to recover a valuable metal containing cerium (Ce) and lanthanum (La) elements in the waste polishing powder, thereby achieving resource reuse. Use purpose.

The invention provides a resource regeneration method for waste polishing powder, which comprises the following steps:

(a) first obtain a waste polishing powder;

(b) impregnation and dissolution, first placing a waste polishing powder into an acidic dissolution solution, performing impregnation and dissolution treatment to form an impregnation liquid containing a rare earth metal element;

(c) filtering and filtering the immersion liquid;

(d) Precipitating, pouring an alkaline precipitant into the filtered impregnation solution to form a mixed solution, purifying by precipitation method, and adjusting the pH value of the mixed solution with a precipitating agent to obtain a first a compound and a second compound, and both the first compound and the second compound contain a rare earth metal element.

According to the above, one of the effects achieved by the present invention is that the rare earth metal elements in the waste polishing powder are selectively dissolved by the treatment of the impregnation and dissolution to form different compound forms.

By the above, the second aspect of the invention achieves the effect that the filtered impregnation liquid can be purified by a precipitation method to recover a compound containing a rare earth metal element, which can be directly sold to a professional rare earth metal element resource recovery refinery for resources. Regeneration, after being treated by the resource regeneration method of the present invention, can achieve the purpose of recycling and recycling rare earth element valuable metal resources.

By the above, the third effect of the invention can avoid the waste polishing powder polluting the environment and endangering human health.

For the convenience of the description, the central idea expressed by the present invention in the column of the above summary of the invention is expressed by the specific embodiments. The various items in the embodiments are set forth in proportion to the description and not in the

Please refer to FIG. 1. FIG. 1 is a block diagram of a manufacturing process of the present invention. The method for recycling a waste polishing powder of the present invention comprises the following steps:

Extracting 10, first obtaining a waste polishing powder, wherein the waste polishing powder contains a metal element of cerium (Ce) or lanthanum (La).

Analysis, the waste polishing powder is subjected to the analysis of the content of the metal content of cerium (Ce) and lanthanum (La) as a benchmark for the calculation of the recovery rate of the rare earth metal element. In the present invention, the main target rare earth element analyzed is lanthanum ( Ce), 镧 (La), which is based on Inductively Coupled Plasma (Inductively Coupled Plasma) hereinafter referred to as ICP-AES, and according to the Environmental Protection Agency Environmental Protection Institute's "heavy heavy metal detection method - Wangshui digestion method (NIEAS321.63B)" analysis shows the content of metal elements (Ce) and lanthanum (La) in the waste polishing powder.

Impregnating and etching 20, placing the waste polishing powder into an acidic etching solution for impregnation and erosion, the main purpose of which is to impregnate the waste polishing powder having rare earth metal elements into a cerium (Ce), lanthanum (La) by a caustic solution The metal element impregnating solution selectively dissolves the cerium (Ce) and lanthanum (La) metal elements in the waste polishing powder. In the present invention, the experimental operating condition may be that the etching solution may be selected from sulfuric acid (H). ₂ SO ₄ ), nitric acid (HNO ₃ ), hydrochloric acid (HCl) at least one of them, and the equivalent molar concentration of the dissolution solution may be 1 to 10 N, and the solid-liquid ratio of the waste polishing powder to the dissolution solution may be 0.02 ~0.1g/ml, and the immersion time is 70 ^o C, the immersion time is 1-4 hours, however, the different kinds of dissolution liquid, the concentration of the dissolution solution, the solid-liquid ratio of the waste polishing powder and the dissolution liquid, the immersion temperature and the impregnation The time will affect the reaction effect of the recovery of cerium (Ce) and lanthanum (La) metal elements under the impregnation treatment. The immersion recovery rate (the weight of rare earth elements in the immersion liquid / the rare earth in the waste polishing powder) Element weight) x100%.

Filtering 30, filtering the immersion liquid, preserving the cerium (Ce) and lanthanum (La) metal elements dissolved in the immersion liquid, and removing other impurities not to be recovered by the present invention by filtration;

Precipitating 40, pouring an alkaline precipitant into the filtered impregnation liquid to form a mixed solution, purifying by precipitation, and adjusting the pH of the mixed solution with a precipitating agent, the main purpose of which is to use a precipitating agent The cerium (Ce) and lanthanum (La) metal element ions in the immersion liquid are separated and precipitated to form a first compound containing a cerium metal element and a second compound containing a cerium metal element. However, in the present invention, the precipitating agent may be It is selected from sodium hydroxide (NaOH) or ammonia water (NH ₃ ).

Please refer to FIG. 2 , which is a preferred embodiment of the manufacturing process of the present invention. The waste polishing powder is firstly analyzed by ICP-AES for the content of cerium (Ce) and lanthanum (La) metal elements in the waste polishing powder. For the subsequent calculation of the recovery ratio of cerium (Ce) and lanthanum (La) metal elements and performing the impregnation and erosion treatment 20, in the experimental results of the present invention, the optimum operating conditions are the selection of the etching solution for the nitric acid (HNO). ₃ ), and the equivalent molar concentration of the dissolution solution is 10N, and the solid-liquid ratio of the waste polishing powder to the dissolution solution is 0.06g/ml, and the immersion time is 70 ^o C, the immersion time is 3 hours, and the magnet is stirred under the environment. In the process, the metal elements of cerium (Ce) and lanthanum (La) in the waste polishing powder are thus impregnated and dissolved in the etching solution to form an optimal immersion liquid, which is converted into different compound types and can be analyzed by ICP-AES. It is known that the recovery rates of cerium (Ce) and lanthanum (La) metal elements in the impregnation are close to 100%.

However, the 30 immersion liquid is treated by filtration to remove the substance not to be recovered by the present invention, and the collected immersion liquid containing cerium (Ce) and lanthanum (La) metal elements is further subjected to a precipitation treatment 40, in this embodiment. The precipitant used is ammonia water (NH ₃ ). First, the ammonia water (NH ₃ ) is poured into the filtered immersion liquid, and the pH of the mixed liquid is adjusted to 0.9 for the first time with ammonia water, please refer to FIG. 3 3 is a SEM image of the first precipitation treatment of the present invention, and the mixed solution precipitates to form a first compound of cerium hydroxide (Ce(OH) ₄ ), wherein, as shown in FIG. 4 , 4 is the EDS data analysis chart after the first precipitation treatment of the present invention. The molecular weight of the cerium (Ce) metal element in the cerium hydroxide is estimated to be 67.32% by the molecular formula of cerium hydroxide, and the first compound of cerium hydroxide is The EDS analysis was found to be 74.43% and greater than 67.32%, so the purity of the first compound of cerium hydroxide was close to 100%, and the recovery of the cerium (Ce) metal element of the first compound was only 40% by ICP-AES analysis.

After the first compound whose pH value is precipitated is recovered by filtration, the pH is adjusted a second time with ammonia water. When the pH of the mixture reaches 9, please refer to FIG. 5, which is shown in FIG. Invented in the SEM image after the second precipitation treatment, the mixture precipitates to form a second compound of lanthanum hydroxide (La(OH) ₃ ) and a first compound of cerium hydroxide (Ce(OH) ₄ ), wherein Please refer to FIG. 6. FIG. 6 is a diagram showing the EDS data analysis of the second precipitation treatment of the present invention. The molecular weight of the cerium (Ce) metal element in the cerium hydroxide is estimated to be 67.32% by the molecular formula of cerium hydroxide. The first compound of barium hydroxide was found to be 20.39% by EDS analysis, so the purity of the first compound of barium hydroxide was about 30.3%, and the molecular formula of barium hydroxide estimated the weight percentage of barium (La) metal element in barium hydroxide. It is 75.52%, and the first compound of barium hydroxide is 10.85% by EDS analysis, so the first compound of barium hydroxide has a purity of about 14.36%, and is analyzed by ICP-AES, when the pH of the mixture is 9 a cerium (Ce) metal element of the first compound and a lanthanum (La) metal element of the second compound Recycling can reach 100%. The above calculation methods are all the mathematical calculation process of the well-known, and will not be elaborated here.

In summary, the present invention selectively dissolves the cerium (Ce) and lanthanum (La) metal elements in the waste polishing powder by means of impregnation and erosion, and then removes the impurities by filtration, and then adds a precipitating agent to precipitate. The method further adjusts the pH value of the mixed solution to obtain a compound containing cerium (Ce) and lanthanum (La), and can be directly sold to a professional cerium (Ce), lanthanum (La) metal element resource recovery refinery. The resource is regenerated, and after the resource regeneration method of the present invention is processed, the purpose of recycling the waste polishing powder resource can be achieved, and the utilization value can be extended in the industry, and the waste polishing powder can be prevented from polluting the environment and endangering human health.

While the invention has been described in terms of a preferred embodiment, the various embodiments may The above embodiments are merely illustrative of the invention and are not intended to limit the scope of the invention. All modifications or changes made without departing from the spirit of the invention are within the scope of the invention.

10. . . extract

20. . . Impregnation erosion

30. . . filter

40. . . precipitation

[Fig. 1] is a block diagram of a production flow of the present invention. [Fig. 2] A preferred embodiment of the manufacturing process of the present invention. Fig. 3 is a SEM image of the present invention after the first precipitation treatment. Fig. 4 is a graph showing the analysis of EDS data after the first precipitation treatment of the present invention. Fig. 5 is a SEM image of the present invention after the second precipitation treatment. Fig. 6 is a graph showing the analysis of EDS data after the second precipitation treatment of the present invention.

10. . . extract

20. . . Impregnation erosion

30. . . filter

40. . . precipitation

Claims (10)

A method for recycling waste polishing powder, comprising the steps of: (a) extracting, first obtaining a waste polishing powder; (b) impregnating and eroding, placing the waste polishing powder into an acidic dissolution liquid, and mixing to form a (c) filtering, filtering the impregnation liquid; (d) precipitating, pouring an alkaline precipitant into the filtered impregnation liquid to form a mixed solution, and purifying by precipitation method. A first compound containing a rare earth metal element and a second compound containing a rare earth metal element can be obtained separately. The method for recycling a waste polishing powder according to claim 1, wherein the etching solution is at least one of sulfuric acid, nitric acid, and hydrochloric acid. The method for recycling a waste polishing powder according to claim 1, wherein the waste polishing powder comprises a composition selected from the group consisting of cerium (Ce) and lanthanum (La). The method for recycling a waste polishing powder according to claim 1, wherein the concentration of the etching solution is 1 to 10 N. The method for recycling a waste polishing powder according to claim 1, wherein the solid-liquid ratio of the waste polishing powder to the etching solution is 0.02 to 0.1 g/ml. The method for recycling a waste polishing powder according to claim 1, wherein the immersion etching temperature is 27 to 70 ^o C. The method for recycling a waste polishing powder according to claim 1, wherein the immersion time of the immersion erosion is 1 to 4 hours. The method for recycling a waste polishing powder according to claim 1, wherein the precipitating agent is sodium hydroxide or ammonia water. The method for regenerating a waste polishing powder according to claim 1, wherein the first liquid compound containing a cerium (Ce) metal element is precipitated by first adjusting the pH to 0.9. The resource regeneration method of the waste polishing powder according to claim 9, wherein the mixture is subjected to the first adjustment of the pH-precipitated first compound, and then the pH is adjusted to 9 by the precipitating agent for a second time. The mixed solution can precipitate the first compound containing the cerium (Ce) metal element and the second compound containing the lanthanum (La) metal element.