阅读说明：本技术 一种分离回收砂浆中砷化镓的方法 (Method for separating and recovering gallium arsenide in mortar ) 是由 彭杰 于 2021-09-24 设计创作，主要内容包括：本发明公开了一种分离回收砂浆中砷化镓的方法,涉及晶片制造技术领域。本发明的一种分离回收砂浆中砷化镓的方法,所述方法是将废弃砂浆进行沉淀分离得到切削油和固体混合物,再将混合固体用混合酸液处理分离得到碳化硅和含镓溶液,最后将含镓溶液进行还原得到砷化镓固体。本发明公开了一种分离回收砂浆中砷化镓的方法,利用砷化镓和氮化硅之间物理性质的差异进行分离回收,分离彻底,便于再次生产利用,能够有效降低生产成本。(The invention discloses a method for separating and recovering gallium arsenide in mortar, and relates to the technical field of wafer manufacturing. The invention relates to a method for separating and recycling gallium arsenide in mortar, which comprises the steps of carrying out precipitation separation on waste mortar to obtain a mixture of cutting oil and solid, then treating and separating the mixed solid by using mixed acid liquor to obtain silicon carbide and a gallium-containing solution, and finally reducing the gallium-containing solution to obtain gallium arsenide solid. The invention discloses a method for separating and recycling gallium arsenide in mortar, which separates and recycles the gallium arsenide and silicon nitride by using the difference of physical properties, is thorough in separation, is convenient for secondary production and utilization, and can effectively reduce the production cost.)

1. A method for separating and recycling gallium arsenide in mortar is characterized in that waste mortar is subjected to precipitation separation to obtain a cutting oil and solid mixture, the mixed solid is treated and separated by mixed acid liquid to obtain silicon carbide and gallium-containing solution, and finally the gallium-containing solution is reduced to obtain gallium arsenide solid.

2. The method for separating and recovering gallium arsenide in mortar according to claim 1, wherein said method comprises the following steps:

pretreatment: standing and precipitating the waste mortar, recovering supernatant to obtain cutting oil after layering, and carrying out acid washing treatment on a lower-layer solid mixture by using a dilute hydrochloric acid solution;

and (3) high-temperature roasting: placing the solid mixture subjected to acid washing in a high-temperature heating furnace, heating until the solid mixture becomes powder, cooling to room temperature, and taking out;

acid treatment: adding the roasted powder into the mixed acid solution, stirring until the reaction is finished, filtering, collecting filtrate for later use, washing a filter cake to be neutral by using water, and drying to obtain silicon carbide;

reduction: and adding a reducing solution into the filtrate collected in the acid treatment step, filtering after the reaction is finished, washing a filter cake to be neutral by using water, and drying to obtain the gallium arsenide solid.

3. The method for separating and recovering gallium arsenide in mortar according to claim 2, wherein in said pretreatment step, the mass fraction of the dilute hydrochloric acid solution is 15% -18%.

4. The method for separating and recovering gallium arsenide in mortar according to claim 3, wherein the temperature of the high temperature calcination step is 300-400 ℃.

5. The method for separating and recovering gallium arsenide in mortar according to claim 4, wherein said mixed acid solution comprises concentrated nitric acid, concentrated hydrochloric acid and sodium permanganate.

6. The method for separating and recovering gallium arsenide in mortar according to any of claims 1 to 4, wherein said mixed acid solution comprises the following raw materials in parts by weight: 30-40 parts of concentrated nitric acid, 60-100 parts of concentrated hydrochloric acid and 10-20 parts of sodium permanganate solution.

7. The method for separating and recovering gallium arsenide in mortar according to claim 6, wherein the mass fraction of said concentrated nitric acid is 64-68%, the mass fraction of said concentrated hydrochloric acid is 32-37%, and the mass fraction of said sodium permanganate is 35-43%.

8. The method for separating and recovering gallium arsenide in mortar according to claim 7, wherein said reducing solution is thiourea dioxide solution, and the mass fraction of thiourea dioxide is 25-32 wt%.

9. The method for separating and recovering gallium arsenide in mortar according to claim 8, wherein in said reducing step, the volume ratio of the filtrate to the thiourea dioxide solution is (4.5-6): 1.

Technical Field

The invention relates to the technical field of wafer manufacturing, in particular to a method for separating and recycling gallium arsenide in mortar.

Background

In the rapid development of semiconductor technology, gallium arsenide is a second generation semiconductor material with great importance in many fields, and its gallium arsenide wafer is an important intermediate process product object. The gallium arsenide wafer is usually prepared by adopting a multi-wire cutting technology, the multi-wire cutting technology uses a form that mortar is coated on a steel wire to grind the gallium arsenide crystal, the diameter of the steel wire used in the prior art is 0.1mm, the wire slot distance is 0.57mm, the thickness of the wafer after cutting is 0.45mm, the cutting part of the gallium arsenide crystal and the steel wire is ground into powder by the mortar, the powder is mixed into the mortar and taken away by the mortar, about 20% of gallium arsenide materials in the prior art enter the mortar and are taken away by the mortar, the quality effect of the mortar grinding crystal can be influenced after the gallium arsenide materials enter the mortar, the heat conductivity of the mortar can be reduced, the heat dissipation effect of the mortar is weakened, and the quality stability of wafer production is not ensured.

The existing solution is that after the mortar is ground and produced for a certain number of times, the mortar is integrally replaced, new mortar is used for production, the waste mortar containing a large amount of gallium arsenide abrasive dust is directly scrapped, and a large amount of cost is spent to be treated by a hazardous solid treatment company, so that the working labor intensity is greatly increased, and meanwhile, gallium arsenide raw materials in the waste mortar are not purified and recovered, so that the raw material waste is greatly caused, and the production cost is increased.

In the existing technology for recycling the waste containing gallium arsenide, complex steps such as electrolysis, high-temperature calcination and the like are mostly needed for treatment, for example, the existing Chinese invention patent with the publication number of "CN 102061389A" and the patent name of "a method for recycling arsenic and gallium from waste containing gallium arsenide" needs to utilize the electrolysis technology with the publication number of "CN 102061389A" and the patent name of "a method for recycling arsenic and enriching heavy metals from metallurgical sludge containing arsenic", a high-temperature calcination method is utilized, while the Chinese invention patent with the publication number of "CN 101857918A" and the patent name of "a method for purifying and recycling gallium and arsenic of gallium arsenide waste" realizes the recycling and separation of gallium by a method of high-temperature calcination and acidification for re-electrolysis, and the methods not only have higher difficulty in recycling arsenic and gallium, higher energy consumption and are not beneficial to control of the production cost, and new waste is generated in the treatment process.

Disclosure of Invention

Aiming at the problems, the invention aims to disclose a method for separating and recycling gallium arsenide in mortar, which separates and recycles the gallium arsenide and silicon nitride by using the difference of physical properties, has thorough separation, is convenient for secondary production and utilization, and can effectively reduce the production cost.

The method comprises the steps of carrying out precipitation separation on waste mortar to obtain a cutting oil and solid mixture, treating and separating the mixed solid with mixed acid liquor to obtain silicon carbide and a gallium-containing solution, and finally reducing the gallium-containing solution to obtain gallium arsenide solid.

Further, the method specifically comprises the following steps:

pretreatment: standing and precipitating the waste mortar, recovering supernatant to obtain cutting oil after layering, and carrying out acid washing treatment on a lower-layer solid mixture by using a dilute hydrochloric acid solution;

and (3) high-temperature roasting: placing the solid mixture subjected to acid washing in a high-temperature heating furnace, heating until the solid mixture becomes powder, cooling to room temperature, and taking out;

acid treatment: adding the roasted powder into the mixed acid solution, stirring until the reaction is finished, filtering, collecting filtrate for later use, washing a filter cake to be neutral by using water, and drying to obtain silicon carbide;

reduction: and adding a reducing solution into the filtrate collected in the acid treatment step, filtering after the reaction is finished, washing a filter cake to be neutral by using water, and drying to obtain the gallium arsenide solid.

Further, in the pretreatment step, the mass fraction of the dilute hydrochloric acid solution is 15-18%.

Further, in the high-temperature roasting step, the heating temperature is 300-400 ℃.

Further, the mixed acid liquid comprises concentrated nitric acid, concentrated hydrochloric acid and sodium permanganate.

Further, the mixed acid liquid comprises the following raw materials in parts by weight: 30-40 parts of concentrated nitric acid, 60-100 parts of concentrated hydrochloric acid and 10-20 parts of sodium permanganate solution.

Further, the mass fraction of the concentrated nitric acid is 64-68%, the mass fraction of the concentrated hydrochloric acid is 32-37%, and the mass fraction of the sodium permanganate is 35-43%.

Further, the reducing solution is a thiourea dioxide solution, and the mass fraction of the thiourea dioxide is 25-32 wt%.

Furthermore, in the reduction step, the volume ratio of the filtrate to the thiourea dioxide solution is (4.5-6) to 1.

The invention has the beneficial effects that:

1. the invention discloses a method for separating and recycling gallium arsenide in mortar, which utilizes the property difference that silicon carbide has stable property and gallium arsenide is easy to dissolve in strong oxidizing acid, uses the strong oxidizing acid to separate the silicon carbide and the gallium arsenide by dissolving gallium arsenide powder, and uses a strong reducing agent to reduce the gallium arsenide in the solution, thereby realizing the separation, recycling and reusing of waste mortar.

2. The method for recovering the gallium arsenide is based on the fact that the difference of the physicochemical properties of the silicon carbide and the gallium arsenide is utilized to separate, the separation effect is good, new wastes cannot be generated in the process, and the method is environment-friendly.

Detailed Description

The present invention will be described in detail with reference to specific examples below:

the invention relates to a method for separating and recycling gallium arsenide in mortar, which comprises the steps of carrying out precipitation separation on waste mortar to obtain a mixture of cutting oil and solid, then treating and separating the mixed solid by using mixed acid liquor to obtain silicon carbide and a gallium-containing solution, and finally reducing the gallium-containing solution to obtain gallium arsenide solid. The method comprises the following specific steps:

example one

Pretreatment: and standing and precipitating the waste mortar, recovering supernatant to obtain cutting oil after layering, adding a lower-layer solid mixture into 18 wt% of dilute hydrochloric acid solution, stirring and mixing to remove impurities by acid washing until no bubbles are generated on the surface of the solid mixture, completing cleaning, filtering, and cleaning a filter cake by using water.

And (3) high-temperature roasting: placing the solid mixture subjected to acid cleaning in a high-temperature heating furnace, heating to 350 ℃, cracking carbon chains of cutting oil polyethylene glycol remained in the mixture at high temperature to form volatile lysate, volatilizing hydrochloric acid remained in the mixture, keeping the temperature, heating until the solid mixture becomes powder, cooling to room temperature, and taking out;

acid treatment: respectively taking 30 parts by weight of 65 wt% concentrated nitric acid, 60 parts by weight of 37 wt% concentrated hydrochloric acid and 20 parts by weight of 35 wt% sodium permanganate, stirring and mixing to prepare mixed acid liquid, adding the roasted powder into the mixed acid liquid, stirring until no bubbles are generated on the surface of the powder, completing the reaction, filtering, collecting gallium-containing filtrate for later use, washing a filter cake to be neutral by using water, and drying to obtain silicon carbide;

reduction: adding 32 wt% thiourea dioxide solution into the filtrate collected in the acid treatment step according to the volume ratio of 5:1 as a reducing solution, starting to react to generate a precipitate, namely gallium arsenide, stirring and reacting for 30min, filtering, washing a filter cake to be neutral by using water, drying to obtain gallium arsenide solid, storing the filtrate, adding the filtrate obtained in the acid treatment step of the next batch, and continuously recycling.

Example two

Pretreatment: standing and precipitating the waste mortar, recovering supernatant to obtain cutting oil after layering, adding a lower-layer solid mixture into a 16 wt% dilute hydrochloric acid solution, stirring and mixing to remove impurities by acid washing until no bubbles are generated on the surface of the solid mixture, completing cleaning, filtering, and cleaning a filter cake by using water.

And (3) high-temperature roasting: placing the solid mixture subjected to acid cleaning in a high-temperature heating furnace, heating to 400 ℃, cracking carbon chains of cutting oil polyethylene glycol remained in the mixture at high temperature to form volatile lysate, volatilizing hydrochloric acid remained in the mixture, keeping the temperature, heating until the solid mixture becomes powder, cooling to room temperature, and taking out;

acid treatment: respectively taking 35 parts by weight of 68 wt% concentrated nitric acid, 100 parts by weight of 32 wt% concentrated hydrochloric acid and 15 parts by weight of 40 wt% sodium permanganate, stirring and mixing to prepare mixed acid liquor, adding the roasted powder into the mixed acid liquor, stirring until no bubbles are generated on the surface of the powder, completing the reaction, filtering, collecting gallium-containing filtrate for later use, washing a filter cake to be neutral by using water, and drying to obtain silicon carbide;

reduction: adding 30 wt% thiourea dioxide solution into the filtrate collected in the acid treatment step according to the volume ratio of 6:1 as a reducing solution, starting to react to generate a precipitate, namely gallium arsenide, stirring and reacting for 30min, filtering, washing a filter cake to be neutral by using water, drying to obtain gallium arsenide solid, storing the filtrate, adding the filtrate obtained in the acid treatment step of the next batch, and continuously recycling.

EXAMPLE III

Pretreatment: and standing and precipitating the waste mortar, recovering supernatant to obtain cutting oil after layering, adding a lower-layer solid mixture into 15 wt% of dilute hydrochloric acid solution, stirring and mixing to remove impurities by acid washing until no bubbles are generated on the surface of the solid mixture, completing washing, filtering, and washing a filter cake by water.

And (3) high-temperature roasting: placing the solid mixture subjected to acid cleaning in a high-temperature heating furnace, heating to 300 ℃, cracking carbon chains of cutting oil polyethylene glycol remained in the mixture at high temperature to form volatile lysate, volatilizing hydrochloric acid remained in the mixture, keeping the temperature, heating until the solid mixture becomes powder, cooling to room temperature, and taking out;

acid treatment: respectively taking 40 parts by weight of 64 wt% concentrated nitric acid, 80 parts by weight of 35 wt% concentrated hydrochloric acid and 10 parts by weight of 43 wt% sodium permanganate, stirring and mixing to prepare mixed acid liquor, adding the roasted powder into the mixed acid liquor, stirring until no bubbles are generated on the surface of the powder, completing the reaction, filtering, collecting gallium-containing filtrate for later use, washing a filter cake to be neutral by using water, and drying to obtain silicon carbide;

reduction: adding a 25 wt% thiourea dioxide solution into the filtrate collected in the acid treatment step according to the volume ratio of 4.5:1 as a reducing solution, starting to react to generate a precipitate, namely gallium arsenide, stirring and reacting for 30min, filtering, washing a filter cake to be neutral by using water, drying to obtain gallium arsenide solid, storing the filtrate, adding the filtrate obtained in the acid treatment step of the next batch, and continuously recycling.

Comparative example 1

The difference between the comparative example and the first example is that the mixed acid solution in the comparative example is a mixed solution of concentrated sulfuric acid and concentrated hydrochloric acid, wherein the mass fraction of the concentrated sulfuric acid is 95-98 wt%, and the mass fraction of the concentrated hydrochloric acid is 32-37 wt%.

Comparative example No. two

The comparative example differs from example one in that the comparative example uses a sodium sulfate solution instead of a thiourea dioxide solution in the reduction step.

The separation situation and the recovery purity of gallium arsenide and silicon carbide in the waste mortar of the first embodiment to the third embodiment and the first comparative embodiment to the second comparative embodiment are detected, and the detection results are shown in table 1:

as can be seen from the data in Table 1, the method can effectively separate the gallium arsenide and the silicon carbide in the waste mortar; when the mixed acid component does not contain concentrated nitric acid with strong oxidizing property, silicon carbide and gallium arsenide components in the mortar cannot be effectively separated; when the waste mortar is dissolved by the oxidizing acid but is reduced by the non-reducing agent, only the silicon carbide component can be separated, and the gallium arsenide component dissolved in the oxidizing acid cannot be reduced, namely, only the silicon carbide component can be recovered.

Although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the spirit and scope of the invention as defined in the appended claims. The techniques, shapes, and configurations not described in detail in the present invention are all known techniques.