TWI712559B - Separation method of silicon carbide and silicon (1) - Google Patents

Abstract

A method for separating silicon carbide and silicon includes a pretreatment step, a dispersion step, a pH adjustment step, a collection step, a mixing step, a standing step, a centrifugation step, and a drying step. The present invention can separate the silicon carbide and silicon in the silicon wafer cutting waste by using a less toxic organic solvent, and by first adjusting the target acid-base value, and then adding a trapping agent to separate the silicon carbide and silicon One separation operation procedure can be achieved, and high-recovery silicon carbide and high-grade silicon can be obtained under the best separation conditions, and the separation efficiency of silicon carbide is more than 70%, and it can also separate particles below 10 μm, thereby reducing production The cost of waste disposal of solar cells and achieve the goal of circular economy.

Description

Separation method of silicon carbide and silicon (1)

The present invention relates to a method for separating silicon carbide and silicon, in particular to a method for directly separating and recycling silicon carbide and silicon in silicon wafer cutting waste in a single separation operation procedure.

Solar cells are manufactured from silicon wafers. Generally speaking, the manufacturing method of silicon wafers is to first manufacture silicon ingots, and then use multiple wire saws to cut the silicon ingots into multiple silicon wafers. In order for the wire saw to cut the silicon ingot smoothly, cutting oil such as polyethylene glycol and silicon carbide abrasive must be added. In the process of cutting silicon ingots with iron wire saws, a lot of silicon becomes waste, and the addition of silicon carbide, polyethylene glycol and worn iron wire saws for cutting constitutes silicon wafer cutting waste. In other words, silicon wafer cutting waste contains components such as silicon carbide, silicon, iron filings, polyethylene glycol, and water.

At present, most of the silicon wafer cutting waste is sent to the final disposal site for landfill treatment. However, due to the gradual decrease in the capacity of existing landfills and Taiwan’s narrow and densely populated land, it is difficult to open new landfill sites, which gradually increases the cost of waste disposal, resulting in the illegal disposal of silicon wafer cutting waste from time to time.

In order to solve the above problems, the conventional technology recovery methods include: high temperature heat treatment, aluminum-silicon alloy method, electric field separation method, wet vortex cone sorting method, heavy liquid centrifugation method, phase transfer method, double-layer organic solvent sedimentation method, foam Flotation and so on.

The high-temperature heat treatment method uses the melting point difference between silicon carbide and silicon to separate the two. The problem with this method is: first, it must be heated in a high temperature environment of 1420~1500℃, which is quite energy-consuming; second, the steps are complicated.

The aluminum-silicon alloy method first converts silicon carbide into silicon to obtain silicon-aluminum blocks, and then performs acid solution or electrolytic treatment to remove aluminum and aluminum carbide. The problem with this method is that it must be heated in a high temperature environment of 1500°C, which consumes energy; second, the steps are complicated.

The electric field separation method uses the difference in the boundary potential between silicon carbide and silicon, the influence of the electric field is also different, and the gravitational force is different for different particle sizes, so as to separate silicon carbide and silicon. The problem with this method is that the separation effect is not ideal and the recovery rate is poor.

The wet vortex cone sorting method uses two pumps and three wet vortex cones to recycle silicon carbide in series. The problem with this method is that it is suitable for particles with a particle size of about 10 to 300 μm. For silicon carbide and silicon fine particles with a particle size of less than 10 μm, the separation efficiency of silicon carbide is reduced.

The heavy-liquid centrifugation method uses different densities and particle sizes of silicon carbide and silicon to prepare mixed heavy liquids of bromoform and ethanol in different proportions, and centrifuge them for centrifugal separation. The phase transfer method uses the difference in surface hydrophilicity and hydrophobicity and specific gravity of silicon carbide and silicon for separation. The problems with these two methods are: first, the use of bromoform and other toxic substances is harmful to the human body and the environment; second, the steps are complicated.

The two-layer organic solvent sedimentation method uses two organic solvents with different densities and polarities, such as carbon tetrachloride and epichlorohydrin, to separate and sediment silicon carbide and silicon. The problem with this method is that both carbon tetrachloride and epichlorohydrin are poisonous and harmful to the human body and the environment.

The foam flotation method is to add hydrofluoric acid and change the oxidation-reduction potential, and use flotation to separate silicon carbide and silicon. The problem with this method is: first, hydrofluoric acid is a poisonous substance, which is harmful to the human body and the environment; second, because hydrofluoric acid dissolves silicon, silicon may not be separated by floating but dissolved by hydrofluoric acid; Third, it is suitable for particles with a particle size of about 10~300 μm. For silicon carbide and silicon fine particles with a particle size of less than 10 μm, the separation efficiency of silicon carbide is reduced.

Please refer to the TW 201040109 patent specification on page 5 from the bottom line 1 to page 6 at line 4 of the first paragraph. In order to recover high-purity and high-yield silicon powder from the silicon mud during the silicon ingot cutting process, TW 201040109 The patent case uses a two-stage particle phase transfer method, which utilizes the difference in hydrophilicity and hydrophobicity of the surface of silicon powder and silicon carbide powder, and the difference in specific gravity between silicon powder and silicon carbide powder. Through the separation of the oil phase and the water phase, it is effectively recovered High-purity silicon powder and silicon carbide powder.

However, according to the third paragraph of page 11 to the first paragraph of page 12 of the TW 201040109 patent specification, the TW 201040109 patent actually uses the difference in surface affinity and specific gravity of silicon carbide and silicon for separation, and bromine must be used. Otherwise, the separation efficiency of silicon carbide cannot be improved.

Furthermore, the silicon carbide separation efficiency in the first stage of the TW 201040109 patent case is only 63.98% (recovery rate 83.1% multiplied by 77% grade multiplied by 100%), which is less than 70%. Therefore, the TW 201040109 patent case must undergo the second stage of separation, or even the third stage of separation, to further increase the silicon carbide separation efficiency to equal to or exceed 70%.

It is worth mentioning that the TW 201040109 patent case added sodium hexametaphosphate before adjusting the target pH. Because sodium hexametaphosphate can only promote the separation of silicon carbide and silicon particles in the mixed slurry, avoid sedimentation or agglomeration, so that the particles to be dispersed can be stably dispersed in the medium. This effect is called dispersion. This is Because of the characteristics of the dispersant, there is no need to adjust the target pH in advance. Therefore, the step of adding sodium hexametaphosphate is a dispersion step.

Sodium hexametaphosphate is a dispersing agent and it is well-known notification common knowledge. You can refer to patent cases such as TW 201527445, TW 201545808, TW 201609238, TW 201612330, TW 201712076, etc., and the website of Taiwan Chunghwa Chemical Industry Co., Ltd. https://www.chciw .com.tw/index.php/ch/products/product_moreinfo/id/294.html.

The research paper "Silicon recovery from cutting slurry by phase transfer separation" by HP Hsu, WP Huang, CF Yang, CW Lan and others (hereinafter referred to as literature 1) was published in the journal Separation and Purification Technology, Volume 133, (2014) p. 1 -7. The abstract of Literature 1 reveals that based on the difference in hydrophobicity between silicon and silicon carbide, it is recommended that diesel be used in the phase transfer method. Because silicon carbide is more hydrophobic than silicon, the emulsified phase is rich in silicon carbide particles. Silicon powder with a purity of 95 wt% can be obtained, and the yield is about 80%. Many factors that affect separation efficiency, such as emulsification, are further discussed.

The first paragraph of 2.1 "Sample Capability Testing and Preparation" on page 2 of Document 1 discloses the pre-processing steps, and the second paragraph discloses the gravity sedimentation step. The second paragraph of 2.2 "Phase Transfer Separation Method" on page 2 of Document 1 discloses adding water (dispersion step), adjusting the pH value (pH adjustment step), adding diesel fuel and stirring with a mixer for 40 seconds (mixing step) and standing still 1.5 hours (standstill step) and other steps.

The first limitation of the method in Document 1 is to add a gravity settling step between the pretreatment step and the dispersion step. In other words, Document 1 must first use the gravity sedimentation method to remove the large silicon carbide particles in the silicon mud, and then separate the small particles of silicon carbide and silicon powder using diesel oil and water using the above procedures. Therefore, the method in Document 1 is only suitable for the separation of small particles of silicon carbide and silicon powder. However, when the large particles of silicon carbide in the silica mud are removed by gravity sedimentation, some of the large particles of silica powder in the silica mud will also be removed. This part is ignored and not mentioned and discussed in Literature 1. In addition, if the large silicon carbide particles in the silicon sludge are not settled and removed by gravity sedimentation first, and all the silicon carbide and silicon powder in the silicon sludge are directly separated by the above procedure, the separation efficiency of the two is about 65.9 %, less than 70%. Therefore, literature 1 must carry out the second stage of separation, or even the third stage of separation, to further increase the silicon carbide separation efficiency to equal to or exceed 70%.

The second limitation of the method in Document 1 is: first use the method of gravity sedimentation to remove the large particles of silicon carbide in the silicon mud, and then use the above procedure to transfer the small particles of silicon carbide to the oil-water interface between the oil phase and the water phase. (As shown in Fig.4, Fig.5, Fig.8 in Literature 1), the batch processing capability is poor.

The method in Document 1 is essentially a two-stage treatment method. If the large silicon carbide particles in the silicon sludge are not removed by gravity sedimentation first, and the silicon carbide separation efficiency is lower than 65.9% when the above procedure is used for separation.

The main purpose of the present invention is to provide a method for separating silicon carbide and silicon, which can remove silicon carbide and silicon from silicon wafer cutting waste by using organic solvents with lower toxicity and adjusting the target pH value first. Then add a trapping agent to separate silicon carbide and silicon in one separation operation. The separation efficiency of silicon carbide is above 70%, and it can also separate particles below 10 μm.

Another object of the present invention is to provide a method for separating silicon carbide and silicon, the batch processing capacity is higher than that of the document 1 described in the prior art.

In order to achieve the foregoing objective, the present invention provides a method for separating silicon carbide and silicon, which includes the following steps:

Pre-processing steps: remove water, cutting oil and metal impurities in the cutting waste of a silicon wafer obtained by cutting the silicon ingot to obtain a sample composed of silicon carbide and silicon;

Dispersion step: add water to the sample and mix it to form a mixed slurry, and use an ultrasonic disperser to disperse the silicon carbide and silicon in the mixed slurry;

PH adjusting step: adding an acid adjusting agent or an alkaline adjusting agent to a pH adjusting agent to adjust the pH of the mixed slurry to a target pH of 7;

Capture step: Add a capture agent to capture the silicon carbide contained in the mixed slurry, where the capture agent is Dodecylamine Acetate (DAA), the addition of the capture agent The amount relative to the sample weight of 1 ton is between 0.2~0.5 kg/ton;

Mixing step: use the shaking force generated by a shaker to perform a preliminary mixing of the mixed slurry, add an organic solvent, and use the shaker to perform an advanced mixing to form a mixed solution, wherein the organic solvent is 4-methyl 2-pentanol, the volume ratio of organic solvent and water is between 1:9 to 1:4, the weight of the sample (in g) and the volume of the liquid composed of water and organic solvent (in ml) are solid The liquid ratio is between 1:50 to 3:50;

Standing step: The mixed solution is allowed to stand for a period of time to form an organic solvent phase solution and an aqueous phase solution that are separated from each other up and down, and then take out the organic solvent phase solution and the aqueous phase solution respectively, where the organic solvent phase solution is rich in silicon carbide , The aqueous solution is rich in silicon;

Centrifugation step: use the centrifugal force generated by a centrifuge to separate the solids and liquids of the organic solvent phase solution, take out the solids of the organic solvent phase solution, and use the centrifugal force generated by a centrifuge to separate the solids and liquids of the aqueous phase solution The liquid is separated and the solids of the aqueous solution are taken out; and

Drying step: Use a dryer to heat the solids of the organic solvent phase solution or the solids of the aqueous phase solution to remove the remaining liquid, thereby obtaining silicon carbide and silicon, respectively.

Preferably, the additive amount of the collector is 0.25 kg/ton relative to the weight of 1 ton of the sample, the volume ratio of organic solvent and water is 1:4, and the weight of the sample (in g) is composed of water and organic solvent. The volume of liquid (in ml) has a solid-liquid ratio of 1:50.

In one embodiment, the steps are as described above, the difference is that the target acid-base value is 5, and the collector is selected from sodium dodecyl sulfate (SDS) and sodium tetradecyl sulfate ( Sodium Tetradecyl Sulfate, Sodium Laureth Sulfate, Sodium Dodecyl Sulfonate, Sodium Decane-1-Sulfonate and p-toluenesulfonate Sodium p-Toluene Sulfonate (Sodium p-Toluene Sulfonate) is one of the groups. The amount of collector added is 0.25~2 kg/ton relative to 1 ton of sample weight. Preferably, the additive amount of the collector is 2 kg/ton relative to the weight of 1 ton of the sample, the volume ratio of organic solvent and water is 1:4, and the weight of the sample (in g) is composed of water and organic solvent The volume of liquid (in ml) has a solid-liquid ratio of 1:50.

In one embodiment, the steps are as described above, the difference is that the target pH is 5, the trapping agent is sodium oleate (NaOL), and the amount of trapping agent added is relative to 1 ton of sample weight Between 4~6 kg/ton. Preferably, the added amount of the collector is 5 kg/ton relative to the weight of 1 ton of the sample, the volume ratio of organic solvent and water is 1:4, and the weight of the sample (in g) is composed of water and organic solvent The volume of liquid (in ml) has a solid-liquid ratio of 1:50.

In one embodiment, the steps are as described above, the difference is that the target acid-base value is 9, the amount of the collector added relative to the sample weight of 1 ton is 0.1~0.25 kg/ton, and the organic solvent is isooctane alkyl. Preferably, the additive amount of the collector is 0.1 kg/ton relative to the weight of 1 ton of the sample, the volume ratio of organic solvent and water is 1:4, and the weight of the sample (in g) is composed of water and organic solvent The volume of liquid (in ml) has a solid-liquid ratio of 1:50.

In one embodiment, the steps are as described above, the difference is that the target pH is 5, the trapping agent is sodium oleate (NaOL), and the amount of trapping agent added is relative to 1 ton of sample weight Between 0.1~1.25 kg/ton, the organic solvent is isooctane. Preferably, the additive amount of the collector is 1.0 kg/ton relative to the weight of 1 ton of the sample, the volume ratio of organic solvent and water is 1:4, and the weight of the sample (in g) is composed of water and organic solvent The volume of liquid (in ml) has a solid-liquid ratio of 1:50.

The effect of the present invention is that the silicon carbide and silicon in the silicon wafer cutting waste can be removed by using a less toxic organic solvent, and by first adjusting the target acid-base value, and then adding a trapping agent to make the silicon carbide and silicon The separation of silicon can be achieved in one separation operation procedure, and high-recovery silicon carbide and high-grade silicon can be obtained under optimal separation conditions, and the separation efficiency of silicon carbide is more than 70%, and it can also separate particles below 10 μm. In turn, it achieves the goal of reducing waste disposal costs when producing solar cells and achieving a circular economy.

Furthermore, compared with the second limitation of Document 1 described in the prior art, the present invention separates all silicon carbide into the oil phase, and the batch processing capacity is higher than that of Document 1 described in the prior art.

The following describes the embodiments of the present invention in more detail in conjunction with the drawings and component symbols, so that those who are familiar with the art can implement it after studying this specification.

1, the present invention provides a method for separating silicon carbide and silicon, including pre-processing step S10, dispersion step S20, pH adjustment step S30, trapping step S40, mixing step S50, standing step S60, and centrifuging step S70 and drying step S80.

Pre-processing step S10: removing water, cutting oil and metal impurities in a silicon ingot cutting waste obtained by cutting the silicon ingot to obtain a sample; the sample is composed of silicon carbide and silicon. More specifically, silicon wafer cutting waste is rich in silicon carbide, silicon, metal impurities (for example, iron filings), cutting oil (for example, polyethylene glycol), and water before any treatment. In the pre-processing step S10, firstly, the silicon crystal rod cutting waste is placed in a dryer (not shown) for preliminary drying at a temperature of 105°C to remove water; secondly, the dried silicon wafer is cleaned by centrifugation with an appropriate amount of ethanol or acetone. The silicon wafer was cut twice to remove the cutting oil; then, the metal impurities were dissolved with an appropriate amount of 30 wt% nitric acid or sulfuric acid, and the powder was centrifuged and dried. Repeat three times; then, the powder was centrifuged with deionized water In order to wash away the nitric acid or sulfuric acid; finally, the powder is dried to obtain a sample. Since water, cutting oil and metal impurities have been completely removed, the sample is only composed of silicon carbide and silicon, and no other substances remain.

Please refer to FIG. 2. FIG. 2 is a schematic diagram of the particle size analysis result of the sample in the pre-processing step S10 of the present invention using a laser particle size analyzer. A laser particle size analyzer (not shown) is used to analyze the particle size of the sample. The analysis results in Figure 2 show that the particle size of the sample is between 0.25 and 5.47 μm, and the average particle size is 0.390 μm. It can be seen that the particle size of the sample is less than 10 μm, which is very suitable for separation and recovery using the liquid-liquid extraction method described later.

Please refer to FIG. 3. FIG. 3 is a schematic diagram of the crystalline state analysis result of the sample in the pre-processing step S10 of the present invention using an X-ray diffractometer. An X-ray diffraction analyzer (not shown) was used to analyze the crystalline form of the sample. The analysis result in Figure 3 shows that the crystalline phase of the sample is dominated by silicon carbide and silicon.

Please refer to FIG. 4. FIG. 4 is a schematic diagram of the structural appearance analysis result of the sample in the pre-processing step S10 of the present invention by using a scanning electron microscope. A scanning electron microscope (not shown) was used to analyze the structural appearance of the sample. The analysis results in Figure 4 show that there are many small particles of silicon attached to the large particles of silicon carbide. The reason is that silicon carbide is added as an abrasive for cutting during the silicon wafer cutting process, and the tiny silicon particles lost during cutting adhere to the larger silicon carbide particles.

Dispersion step S20: add water to the sample and mix it to form a mixed slurry, and use an ultrasonic dispersion machine (not shown) to vibrate and disperse the silicon carbide and silicon in the mixed slurry. Preferably, the mixed slurry is shaken and dispersed for at least twenty minutes.

PH adjusting step S30: adding an acid adjusting agent or a pH adjusting agent of an alkaline adjusting agent to adjust the pH of the mixed slurry to a target pH. Specifically, the acidity regulator is hydrochloric acid or nitric acid, and the alkalinity regulator is sodium hydroxide or potassium hydroxide, and the target acid-base value is between 4-10. After adjusting the target pH of the mixed slurry, pour it into a separatory funnel (not shown).

The trapping step S40: adding a trapping agent for trapping the silicon carbide contained in the mixed slurry. The trapping agent may be a cation trapping agent or an anion trapping agent. The trapping agent is selected from Dodecylamine Acetate (DAA), Sodium Dodecyl Sulfate (SDS), Sodium Tetradecyl Sulfate, and Polyoxyethylene Lauryl Alcohol Sodium Laureth Sulfate, Sodium Dodecyl Sulfonate, Sodium Decane-1-Sulfonate, Sodium p-Toluene Sulfonate, and One of the group consisting of Sodium Oleate (NaOL). The amount of the collector added is between 0.1 and 6 kg/ton relative to the weight of 1 ton of the sample.

Mixing step S50: using the shaking force generated by a shaking machine to perform a preliminary mixing of the mixed slurry. Next, add an organic solvent. Then use a shaker to perform an advanced mixing to form a mixed solution. Preferably, both the primary mixing and advanced mixing operations are maintained for at least fifteen minutes, the organic solvent is 4-methyl-2-pentanol or isooctane, 4-methyl-2-pentanol is slightly soluble in water , Isooctane is insoluble in water, the volume ratio of organic solvent and water is between 1:9 to 1:4, the weight of the sample (in g) and the volume of the liquid composed of water and organic solvent (in ml) The solid-liquid ratio is between 1:50 to 3:50.

Standing step S60: standing the mixed solution for a period of time to form an organic solvent phase solution and an aqueous phase solution that are separated from each other from top and bottom, and then take out the organic solvent phase solution and the aqueous phase solution respectively. Among them, the organic solvent phase solution is rich in silicon carbide, and the aqueous phase solution is rich in silicon. Specifically, the specific gravity of the organic solvent phase solution is less than the specific gravity of the aqueous phase solution, so the organic solvent phase solution is on top and the aqueous phase solution is on the bottom. Use a separatory funnel to first take out the lower aqueous phase solution, and then take out the upper organic solvent phase solution.

Centrifugation step S70: Use the centrifugal force generated by a centrifuge (not shown) to separate the solids and liquids of the organic solvent phase solution, and take out the solids of the organic solvent phase solution. The centrifugal force generated by the centrifuge is used to separate the solids and liquids of the aqueous solution, and take out the solids of the aqueous solution. Among them, the centrifugal condition of the centrifuge is set at 3500 rpm, and the centrifugal time is 30 minutes.

Drying step S80: Use a dryer to heat the solids of the organic solvent phase solution or the solids of the aqueous phase solution to remove the remaining liquid, thereby obtaining silicon carbide and silicon, respectively, to achieve the purpose of recovery. Among them, the drying condition of the dryer is set at 105°C, dried for 24 hours, and then placed at room temperature to cool down and weighed. Finally, analyze the weight of silicon carbide by the silicon carbide abrasive chemical analysis method (CNS-9439, R3109 method), and then calculate the silicon carbide and silicon grade and recovery rate.

In order to further illustrate the effects achieved by the present invention, two control groups, five experimental groups, and five exemplary embodiments will be provided below to represent five actual sample separation experiments.

Control group 1: Use 4-methyl-2-pentanol as the organic phase without adding a trapping agent.

The basic separation conditions are: (1) the sample is sampled and weighed 2g; (2) the organic solvent is 4-methyl-2-pentanol, and the addition amount is 20 ml; (3) the addition amount of deionized water is 80 ml; and (4) No trapping agent is added.

Please refer to Figure 5. Figure 5 is a graph showing the separation and extraction results of samples with different target acid-base values of 4-methyl-2-pentanol without the addition of trapping agent in control group 1. When the target acid-base value is between 3 and 11, as the target acid-base value increases, the silicon carbide grade of the 4-methyl-2-pentanol phase recovery product decreases from 87% to 46%. When the target acid-base value is 5, the silicon carbide recovery rate of the 4-methyl-2-pentanol phase recovery material reaches the highest 44%. As the target acid-base value increases, the silicon carbide recovery rate is reduced to 5%. Although the silicon carbide grade reaches over 80% when the target acid-base value is below 5, the silicon carbide recovery rate is less than 45%. On the other hand, when the target acid-base value is between 3-11, the silicon grade of the water-phase reclaimed material is between 41% and 52%, and the silicon recovery rate of the water-phase reclaimed material is between 82% and 98%. . Although the silicon recovery rate is above 80%, the silicon grade is below 45%.

Because the silicon carbide separation efficiency is the product of the silicon carbide recovery rate and grade in the 4-methyl-2-pentanol phase recovery, the best silicon carbide can be obtained when the target acid-base value of the control group is 5 The separation efficiency is 38.3% ((recovery rate 44% multiplied by 87% grade multiplied by 100%).

Control group two: diesel oil is used as the organic phase, no trapping agent is added.

The basic separation conditions are: (1) the sample is sampled and weighed 2g; (2) the organic solvent is diesel oil and the addition amount is 20 ml; (3) the addition amount of deionized water is 80 ml; and (4) no trapping agent is added .

Please refer to Figure 6. Figure 6 is a graph showing the separation and extraction results of samples with different target acid-base values for the control group 2 diesel without trapping agent. When the target acid-base value is between 3 and 9, as the target acid-base value increases, the grade of silicon carbide in the diesel phase recycle material increases. When the target acid-base value is 9, the silicon carbide grade reaches the highest 78.5%. When the target pH is above 11, the grade of silicon carbide drops. When the target acid-base value is between 3 and 11, as the target acid-base value increases, the recovery rate of silicon carbide in the diesel phase recycle material decreases. On the other hand, when the target acid-base value is between 3 and 11, as the target acid-base value increases, the silicon grade of the water phase reclaimed material decreases, and the silicon recovery rate of the water phase reclaimed material increases. When the target acid-base value is 11, the silicon recovery rate reaches the highest 84.8%.

Because the silicon carbide separation efficiency is the product of the silicon carbide recovery rate and the grade in the diesel phase recovery, the best silicon carbide separation efficiency of 65.9% can be obtained when the target acid-base value of the control group is 3 (recovery rate). 95.8% multiplied by grade 68.8% multiplied by 100%).

It is worth mentioning that the above-mentioned control group two is essentially the method described in the prior art document 1, therefore, the experimental result of the control group two is the experimental result of the document one described in the prior art.

Experimental group 1: Using 4-methyl-2-pentanol as the organic phase, the addition amount of sodium hexametaphosphate is 0.25 kg/ton relative to the sample weight of 1 ton.

The basic separation conditions are: (1) the sample is sampled and weighed 2g; (2) the organic solvent is 4-methyl-2-pentanol, and the addition amount is 20 ml; (3) the addition amount of deionized water is 80 ml; and (4) After the pH adjustment step and before the mixing step, add dispersant: sodium hexametaphosphate. The amount of sodium hexametaphosphate added is 0.25 kg/ton relative to the weight of 1 ton of the sample.

Please refer to Figure 7. Figure 7 shows the 4-methyl-2-pentanol added with sodium hexametaphosphate (dispersant) of experimental group 1 relative to the sample weight of 1 ton as 0.25 kg/ton. The sample is at different target pH values. The separation draws the result graph. When the target acid-base value is between 3 and 5, with the increase of the target acid-base value, the silicon carbide grade and recovery rate of the 4-methyl-2-pentanol phase recovery material gradually increase. When the target acid-base value is 5, the silicon carbide grade reaches the highest 75.5%, and the silicon carbide recovery rate reaches the highest 24.8%. When the target pH is above 5, the grade of silicon carbide and the recovery rate of silicon carbide decrease. On the other hand, when the target acid-base value is between pH 3-11, the silicon grade of the water phase reclaimed product does not change significantly, and the silicon recovery rate is between 88.7%-98.1%. When the target pH value is 5, the silicon grade reaches the highest 49.8%.

Because the silicon carbide separation efficiency is the product of the silicon carbide recovery rate and the grade in the 4-methyl-2-pentanol phase recovery, the best silicon carbide can be obtained when the target acid-base value of the first experimental group is 5 The separation efficiency is 19.8% (recovery rate of 24.8% multiplied by 75.5% of grade multiplied by 100%).

Experimental group 2: With diesel as the organic phase, the dodecylamine acetate addition amount is 0.25 kg/ton relative to the sample weight of 1 ton.

The basic separation conditions are: (1) the sample is sampled and weighed 2g; (2) the organic solvent is diesel oil, and the addition amount is 20 ml; (3) the addition amount of deionized water is 80 ml; and (4) the trapping agent is added: Dodecylamine acetate, the addition amount of dodecylamine acetate is 0.25 kg/ton relative to the sample weight of 1 ton.

Please refer to Figure 8. Figure 8 is a graph showing the separation and extraction results of the sample with different target pH values for the sample weight of 1 ton of dodecylamine acetate (DAA) relative to 1 ton of sample weight of 0.25 kg/ton. When the target acid-base value is between 3 and 7, as the target acid-base value increases, the grade of silicon carbide in the diesel phase reclaimed material increases, and the silicon carbide recovery rate ranges from 82.8% to 99.8%. When the target acid-base value is 7, the silicon carbide grade reaches the highest 68.6%. When the target acid-base value is above 7, the silicon carbide grade and the silicon carbide recovery rate of the diesel phase reclaimed material will decrease. On the other hand, when the target acid-base value is between 3 and 5, as the target acid-base value increases, the silicon level of the water phase reclaimed product increases. When the target pH value is 5, the silicon grade reaches the highest 99.6%. As the target acid-base value increases, the silicon recovery rate of the water phase recyclate increases. When the target acid-base value is 11, the silicon recovery rate reaches the highest 71.5%.

Because the silicon carbide separation efficiency is the product of the silicon carbide recovery rate and the grade in the diesel phase recovery, the best silicon carbide separation efficiency of 64.7% (recovery rate) can be obtained when the target acid-base value of experimental group 2 is 5. 99.8% multiplied by grade 64.8% multiplied by 100%).

Experimental group three: diesel oil is used as the organic phase, and the amount of sodium lauryl sulfate added is 0.25 kg/ton relative to the weight of 1 ton of the sample.

The basic separation conditions are: (1) the sample is sampled and weighed 2g; (2) the organic solvent is diesel oil, and the addition amount is 20 ml; (3) the addition amount of deionized water is 80 ml; and (4) the trapping agent is added: Sodium lauryl sulfate, the addition amount of sodium lauryl sulfate is 0.25 kg/ton relative to the sample weight of 1 ton.

Please refer to Figure 9. Figure 9 is a graph showing the separation and extraction results of samples with different target acid-base values for the sample weight of 0.25 kg/ton relative to 1 ton of diesel fuel added with sodium dodecyl sulfate (SDS). When the target acid-base value is between 3 and 9, as the target acid-base value increases, the grade of silicon carbide in the diesel phase recycle material increases. When the target acid-base value is 9, the silicon carbide grade reaches the highest 74.6%. When the target pH is above 11, the grade of silicon carbide drops. When the target acid-base value is between 3 and 11, as the target acid-base value increases, the recovery rate of silicon carbide in the diesel phase recycle material decreases. On the other hand, when the target acid-base value is between 3-11, the silicon grade of the water-phase reclaimed material is between 42%-96%, and the silicon recovery rate of the water-phase reclaimed material increases. When the target acid-base value is 11, the silicon recovery rate reaches the highest 82.8%.

Because the silicon carbide separation efficiency is the product of the silicon carbide recovery rate and the grade in the diesel phase recovery, the best silicon carbide separation efficiency of 66.6% (recovery rate) can be obtained when the target acid-base value of the experimental group 3 is 7. 87.8% multiplied by grade 75.8% multiplied by 100%).

Experimental group 4: With diesel as the organic phase, the amount of sodium oleate added relative to the sample weight of 1 ton is 0.25 kg/ton.

The basic separation conditions are: (1) the sample is sampled and weighed 2g; (2) the organic solvent is diesel oil, and the addition amount is 20 ml; (3) the addition amount of deionized water is 80 ml; and (4) the trapping agent is added: Sodium oleate, the amount of sodium oleate added is 0.25 kg/ton relative to 1 ton of sample weight.

Please refer to Figure 10. Figure 10 is a graph showing the separation and extraction results of sodium oleate (NaOL) in experimental group 4 with respect to the sample weight of 1 ton of 0.25 kg/ton against different target pH values. When the target acid-base value is between 3 and 7, as the target acid-base value increases, the silicon carbide grade of the diesel phase reclaimed material rises. When the target acid-base value is 7, the silicon carbide grade reaches the highest 66.6%. When the target pH is above 7, the grade of silicon carbide decreases. When the target acid-base value is between 3 and 5, as the target acid-base value increases, the recovery rate of silicon carbide in the diesel phase recycle material increases. When the target acid-base value is 5, the silicon carbide recovery rate reaches the highest 81.8%. When the target pH is above 5, the recovery rate of silicon carbide decreases. On the other hand, when the target acid-base value is between 3-11, there is no significant change in the silicon grade of the water phase reclaimed product, which is between 55% and 42%, and the silicon recovery rate of the water phase reclaimed material will increase. When the target acid-base value is 11, the silicon recovery rate reaches the highest 80.8%.

Because the silicon carbide separation efficiency is the product of the silicon carbide recovery rate and the grade in the diesel phase reclaimed product, the best silicon carbide separation efficiency of 49.7% (recovery rate) can be obtained when the target acid-base value of experimental group 4 is 5. 81.8% multiplied by grade 60.8% multiplied by 100%).

Experimental group 5: Using isooctane as the organic solvent, the addition amount of sodium hexametaphosphate (dispersant) is 0.25 kg/ton relative to the sample weight of 1 ton.

The basic separation conditions are: (1) the sample is sampled and weighed 2g; (2) the organic solvent is isooctane and the addition amount is 20 ml; (3) the addition amount of deionized water is 80 ml; and (4) After the value adjustment step and before the mixing step, add dispersant: sodium hexametaphosphate. The addition amount of sodium hexametaphosphate is 0.25 kg/ton relative to the weight of 1 ton of the sample.

Please refer to Figure 11. Figure 11 is a graph showing the separation and extraction results of isooctane added sodium hexametaphosphate (dispersant) relative to 1 ton of sample weight of 0.25 kg/ton for different target pH values of experimental group 5. . When the target acid-base value is between 3 and 7, with the increase of the target acid-base value, the silicon carbide grade and recovery rate of the isooctane phase recovery material increase. When the target acid value is 7, the silicon carbide grade reaches the highest 75.5%, and the silicon carbide recovery rate reaches the highest 56.8%. When the target pH is above 7, the silicon carbide grade and recovery rate will decrease. On the other hand, when the target acid-base value is between 3 and 7, as the target acid-base value increases, the silicon grade of the water phase reclaimed product rises. When the target acid-base value is 7, the silicon grade reaches the highest 57.8%. When the target pH is above 7, the silicon grade drops. When the target acid-base value is between 3 and 11, there is no significant change in the silicon recovery rate of the water phase reclaimed product, and the silicon recovery rate is between 76.7% and 89.8%.

Because the silicon carbide separation efficiency is the product of the silicon carbide recovery rate and the grade of the isooctane phase recovery, the best silicon carbide separation efficiency of 42.8% can be obtained when the target acid-base value of experimental group 5 is 7. The recovery rate is 56.8% times the grade 75.5% times 100%).

Example 1: Using 4-methyl-2-pentanol as the organic phase, the added collector is dodecylamine acetate (DAA).

The basic separation conditions are: (1) the sample is sampled and weighed 2g; (2) the organic solvent is 4-methyl-2-pentanol, and the addition amount is 20 ml; (3) the addition amount of deionized water is 80 ml; and (4) The trapping agent is dodecylamine acetate (DAA). It can be seen from the above that the volume ratio of 4-methyl-2-pentanol to water is 1:4, and the solid-to-liquid ratio of the weight of the sample to the volume of the liquid composed of water and 4-methyl-2-pentanol is 1: 50. The organic solvent phase will be represented by the 4-methyl-2-pentanol phase below. In the following, the 4-methyl-2-pentanol phase recovery product will represent the solid recovered from the 4-methyl-2-pentanol phase. The recovery rate and grade of silicon carbide refer to 4-methyl-2-pentanol phase. The recovery rate and grade of silicon carbide in the alcohol phase recovery. In the following, the water phase reclaimed material will be used to represent the solid material recovered in the water phase. The silicon recovery rate and grade refer to the silicon recovery rate and grade of the water phase reclaimed material respectively. The following silicon carbide separation efficiency is the product of the silicon carbide recovery rate and the grade in the 4-methyl-2-pentanol phase recovery. The larger the value, the higher the value in the 4-methyl-2-pentanol phase recovery. The higher the recovery rate and grade of silicon carbide, the better the separation effect from the silicon in the reclaimed material in the water phase, which is an index indicating the degree of separation between silicon carbide and silicon.

First, under the premise that the basic separation conditions remain unchanged and the addition amount of dodecylamine acetate relative to the sample weight of 1 ton is 0.25 kg/ton, the target pH value is changed. The purpose is to find out the combination of 4-methyl-2-pentanol and dodecylamine acetate, under which target pH condition, the silicon carbide recovery rate, silicon grade and silicon carbide separation efficiency are all Can reach the highest.

Please refer to Figure 12, Figure 12 is the 4-methyl-2-pentanol added dodecylamine acetate (DAA) in the first embodiment of the present invention relative to the sample weight of 1 ton is 0.25 kg/ton. The separation and extraction result curve graph of the target pH value. The silicon carbide grade and silicon grade are affected by the silicon carbide recovery rate and the silicon recovery rate. When the target acid-base value is between 3 and 5, the silicon carbide recovery rate increases as the target acid-base value increases, and the silicon recovery rate decreases as the target acid-base value increases. This phenomenon means that the silicon carbide content in the 4-methyl-2-pentanol phase recovery increases and the silicon content increases, the silicon content in the water phase recovery decreases and the silicon carbide content decreases, so that the silicon carbide grade increases with the target The acid-base value increased and decreased, but the silicon grade did not change significantly. When the target acid-base value is between 5 and 7, the silicon carbide recovery rate increases as the target acid-base value increases, and the silicon recovery rate increases as the target acid-base value increases. This phenomenon means that the silicon carbide content in the 4-methyl-2-pentanol phase recovery increases and the silicon content decreases, the silicon content increases and the silicon carbide content decreases in the water phase recovery, so that the silicon carbide grade increases with the target As the pH value increases, the silicon grade increases as the target pH value increases. Especially when the target acid-base value is 7, the silicon carbide recovery rate reaches the highest 92.8%, the silicon grade reaches the highest 89.8%, and the silicon carbide separation efficiency reaches the highest 78.9%. However, when the target acid-base value is greater than 7, the silicon carbide recovery rate decreases and the silicon recovery rate increases. This phenomenon means that the silicon carbide content in the 4-methyl-2-pentanol phase recovery decreases and the silicon content decreases, the silicon content increases and the silicon carbide content increases in the water phase recovery, so that the silicon carbide grade increases with the target The pH value increases and decreases, and the silicon grade decreases as the target pH value increases. Especially when the target acid-base value is 11, the silicon recovery rate reaches the highest 92%.

It can be seen from the above that under the premise that the basic separation conditions remain unchanged and the addition amount of dodecylamine acetate relative to the sample weight of 1 ton is 0.25 kg/ton, 4-methyl-2-pentanol and dodecane With the combination of amine acetate, under the condition of the target acid-base value of 7, the silicon carbide recovery rate reaches the highest 92.8%, the silicon grade reaches the highest 89.8%, and the silicon carbide separation efficiency reaches the highest 78.9%.

It is worth mentioning that under the premise that the basic separation conditions remain unchanged and the addition amount of dodecylamine acetate relative to the sample weight of 1 ton is 0.25 kg/ton, as long as the target pH value is controlled between 6~8, the silicon carbide recovery rate and grade are maintained above 80%, the silicon recovery rate is maintained above 70%, the silicon grade is maintained above 80%, and the silicon carbide separation efficiency is maintained above 65%.

Next, under the premise that the basic separation conditions remain unchanged and the target acid-base value is 7, the addition amount of dodecylamine acetate is changed. The purpose is to find out the combination of 4-methyl-2-pentanol and dodecylamine acetate, under which dodecylamine acetate addition amount, the silicon carbide recovery rate, silicon grade and silicon carbide The three separation efficiency can reach the highest.

Please refer to Figure 13. Figure 13 is the separation and extraction of 4-methyl-2-pentanol in the first embodiment of the present invention on the sample weight of different dodecylamine acetate (DAA) added relative to 1 ton Result graph. With the increase in the amount of dodecylamine acetate added, the silicon carbide recovery rate and silicon grade increase, but the silicon carbide grade and silicon recovery rate decrease. However, the silicon grade increases or decreases as the silicon carbide recovery rate increases or decreases. The reason is that as the addition amount of dodecylamine acetate increases, the silicon extracted to the 4-methyl-2-pentanol phase also increases, resulting in a decrease in the silicon recovery rate and a decrease in the silicon carbide grade. When the addition amount of dodecylamine acetate relative to the sample weight of 1 ton is greater than 0.25 kg/ton, the recovery rate of silicon carbide is above 85%. When the addition amount of dodecylamine acetate is 0.25 kg/ton relative to the sample weight of 1 ton, the silicon grade reaches the highest 89.8%.

It can be seen from the above that under the premise that the basic separation conditions remain unchanged and the target acid-base value is 7, the combination of 4-methyl-2-pentanol and dodecylamine acetate can be used in the addition of dodecylamine acetate. When the amount is 0.25 kg/ton relative to the sample weight of 1 ton, the silicon carbide recovery rate can reach up to 92.8%, the silicon grade can reach up to 89.8%, and the silicon carbide separation efficiency can reach up to 78.9%.

It is worth mentioning that under the premise that the basic separation conditions remain unchanged and the target acid-base value is 7, as long as the addition amount of dodecylamine acetate relative to the sample weight of 1 ton is maintained at 0.2~0.5 kg/ ton, silicon carbide recovery rate and grade are maintained above 80%, silicon recovery rate is maintained above 75%, silicon grade is maintained above 80%, and silicon carbide separation efficiency is maintained above 70%.

In addition, because 4-methyl-2-pentanol has a viscosity of 5.1 mPa·s at room temperature and pressure, which is very viscous, the oil droplets in the organic solvent phase formed are large and stable, which contributes to greater carbonization. Extraction of silicon particles.

The following summarizes the silicon carbide separation efficiency of the control group 1, the control group 2, the experimental group 1, the experimental group 2, the first stage of the TW 201040109 patent case, and the first embodiment of the present invention in Table 1.

"Table I" Control group one Control group two Experimental group one Experimental group two TW 201040109 Embodiment 1 of the present invention Silicon carbide separation efficiency 38.3% 65.9% 19.8% 64.7% 63.98% More than 70%

Comparing the experimental results of the first embodiment of the present invention with the control group one, it can be proved that the first embodiment of the present invention is in an environment with a target pH of 7 and the addition amount of dodecylamine acetate is relative to 1 ton. The sample weight is controlled at 0.2~0.5 kg/ton, etc., which can provide dodecylamine acetate to have a better trapping effect on the silicon carbide contained in the mixed slurry, so that the silicon carbide separation efficiency can be reduced from 38.3% Significantly increase to more than 70%, at least an increase of 31.7%.

Comparing the experimental results of the control group 1 with the experimental group 1 can prove that the experimental group 1 is in the environment of the target pH value of 5, and the addition amount of sodium hexametaphosphate is 0.25 kg/ton relative to the sample weight of 1 ton. Under these conditions, not only did it not help to increase the efficiency of silicon carbide separation, but it dropped significantly from 38.3% to 19.8%, a full 18.5% drop. If compared with the first embodiment of the present invention, the silicon carbide separation efficiency of the experimental group 1 is far lower than the silicon carbide separation efficiency of the first embodiment of the present invention, which is a full reduction of at least 50.2%. The reason is: Sodium hexametaphosphate only promotes the separation of silicon carbide and silicon particles in the mixed slurry, avoids sedimentation or agglomeration, and enables the particles to be dispersed to be stably dispersed in the medium. This effect is called dispersion. This is the characteristic of the dispersant, which is different from the trapping effect. Therefore, sodium hexametaphosphate is indeed a dispersant, not a collector, so it is not necessary to adjust the target pH in advance.

If compared with the same stage, the silicon carbide separation efficiency of the first stage of the TW 201040109 patent case is 63.98% (recovery rate 83.1% multiplied by 77% grade multiplied by 100%), while the separation of the first embodiment of the present invention The silicon carbide separation efficiency in the first stage of the method is above 70%. It can be seen that the silicon carbide separation efficiency in the first stage of the method of the TW 201040109 patent is lower than the silicon carbide separation efficiency in the first stage of the separation method of the first embodiment of the present invention. This is why the TW 201040109 patent case must undergo the second stage of separation, or even the third stage of separation, to further improve the silicon carbide separation efficiency to be equal to or exceed the silicon carbide separation efficiency of the first embodiment of the present invention.

Furthermore, compared with the TW 201040109 patent case, the organic solvent selected in the first embodiment of the present invention is 4-methyl-2-pentanol, which has much lower toxicity than bromoform and is less harmful to the human body and the environment.

From the comparison of the experimental results of Example 1 of the present invention and the control group 2, it can be proved that Example 1 of the present invention is in an environment with a target pH of 7 and the addition amount of dodecylamine acetate is relative to 1 ton. The sample weight is controlled at 0.2~0.5 kg/ton and other conditions, which can provide dodecylamine acetate to have a better trapping effect on the silicon carbide contained in the mixed slurry, so that the silicon carbide separation efficiency can be reduced from 65.9% A slight increase to more than 70%, an increase of at least 4.1%.

Comparing the experimental results of the control group two with the experimental group two, it can be proved that when the organic solvent is diesel oil, even if dodecylamine acetate is added, the silicon carbide separation efficiency is not significantly improved.

From the comparison of the experimental results of the first embodiment of the present invention and the second experimental group, it can be proved that the first embodiment of the present invention is in an environment with a target pH of 7 and the addition amount of dodecylamine acetate is relative to 1 ton. The sample weight is controlled at 0.2~0.5 kg/ton, etc., which can provide dodecylamine acetate to have a better trapping effect on the silicon carbide contained in the mixed slurry, plus a specific organic solvent: 4- Methyl-2-pentanol can slightly increase the separation efficiency of silicon carbide from 64.7% to more than 70%, at least 5.3%.

According to the 2017 statistics of the Business Waste Declaration and Management Information System of the Environmental Protection Agency of the Executive Yuan, Taiwan's silicon wafer manufacturing industry generates approximately 16,577 metric tons of silicon wafer cutting waste each year. If the silicon carbide separation efficiency can be increased by 1%, a considerable amount of silicon carbide and silicon can be recycled every year in Taiwan alone. If applied to related industries around the world, the world's annual recycling of silicon carbide and silicon will be even more impressive.

In general, the silicon carbide separation efficiency of the separation method of Example 1 of the present invention is more than 70%, which is greater than 38.3% of the control group 1, 65.9% of the control group 2 (ie, the document 1 described in the prior art), 19.8% of experimental group one, 64.7% of experimental group two, and 63.98% of the first phase of the TW 201040109 patent case. The reason is: before adding dodecylamine acetate, adjust the target acid-base value to 7, the amount of dodecylamine acetic acid added relative to the sample weight of 1 ton is controlled within 0.2~0.5 kg/ton, dodecane Amine acetate can interact with silicon carbide powder in a suitable pH environment to promote separation. At the same time, the applicable organic solvent is limited to 4-methyl-2-pentanol and does not contain bromoform.

If the first embodiment of the present invention is extended to related industries all over the world, the world’s annual recovery of silicon carbide and silicon will far exceed those of the control group one, the control group two (ie, the document one described in the prior art) and the experimental group one. , Experimental group 2 and the first stage of the TW 201040109 patent case, without the need to further carry out the second or even the third stage, which can save huge costs and avoid the risk of environmental pollution by extremely toxic compounds such as bromoform.

In addition, compared to the second limitation of the document 1 described in the prior art, the first embodiment of the present invention separates all silicon carbide into the oil phase, and the batch processing capacity is higher than that of the document 1 described in the prior art.

Even if the person with ordinary knowledge in the technical field of the invention, after referring to the TW 201040109 patent case and the document 1 described in the prior art, there is a reasonable motivation to think of all the steps of the separation method of the first embodiment of the present invention. The organic solvent is diesel oil. And trying to add dodecylamine acetate, only the same results as experimental group two can be obtained. It is absolutely impossible to think of all the technical features of the first embodiment of the present invention, let alone achieve the beneficial effects of the first embodiment of the present invention. Therefore, compared with the TW 201040109 patent case and the literature described in the prior art combined with common knowledge, the embodiment of the present invention is more advanced.

Example 2: Using 4-methyl-2-pentanol as the organic phase, the added collector is sodium dodecyl sulfate (SDS).

The basic separation conditions of the second embodiment of the present invention are roughly the same as those of the first embodiment of the present invention, with the difference that the collector is sodium dodecyl sulfate (SDS).

First, under the premise that the basic separation conditions remain unchanged and the addition amount of sodium lauryl sulfate is 0.25 kg/ton relative to the sample weight of 1 ton, the target pH value is changed. The purpose is to find out the combination of 4-methyl-2-pentanol and sodium lauryl sulfate, under which target pH condition, the silicon carbide recovery rate, silicon grade and silicon carbide separation efficiency are all Can reach the highest.

Please refer to Figure 14. Figure 14 shows the sample weight of 4-methyl-2-pentanol added with sodium dodecyl sulfate (SDS) relative to 1 ton of 0.25 kg/ton. The separation and extraction result curve graph of the target pH value. When the target acid-base value is between 3 and 5, the silicon carbide recovery rate increases as the target acid-base value increases, while the silicon recovery rate increases as the target acid-base value increases. This phenomenon means that the silicon carbide content in the 4-methyl-2-pentanol phase recovery increases and the silicon content decreases, the silicon content increases and the silicon carbide content decreases in the water phase recovery, so that the silicon carbide grade increases with the target As the pH value increases, the silicon grade increases as the target pH value increases. Especially when the target acid-base value is 5, the silicon carbide recovery rate reaches the highest 85.9%, while the silicon grade reaches the highest 83.3%, and the silicon carbide separation efficiency reaches the highest 77.5%. It should be noted that when the target acid-base value is greater than 5, the silicon carbide recovery rate decreases significantly as the target acid-base value increases, but the silicon recovery rate increases slightly as the target acid-base value increases. This phenomenon means that the silicon carbide content in the 4-methyl-2-pentanol phase recovery is greatly reduced and the silicon content is slightly reduced, and the silicon content in the water phase recovery is slightly increased and the silicon carbide content is greatly increased. The silicon carbide grade decreases as the target acid-base value increases, and the silicon grade decreases as the target acid-base value increases.

It can be seen from the above that under the premise that the basic separation conditions remain unchanged and the addition amount of sodium lauryl sulfate is 0.25 kg/ton relative to the sample weight of 1 ton, 4-methyl-2-pentanol and dodecane With the combination of sodium sulphate, under the condition of the target acid-base value of 5, the recovery rate of silicon carbide can reach up to 85.9%, the silicon grade can reach up to 83.3%, and the separation efficiency of silicon carbide can reach up to 77.5%.

It is worth mentioning that under the premise that the basic separation conditions remain unchanged and the addition amount of sodium lauryl sulfate is 0.25 kg/ton relative to the sample weight of 1 ton, as long as the target acid-base value is controlled between From 4.5 to 5.5, the recovery rate of silicon carbide is maintained above 80%, the grade of silicon carbide is maintained above 85%, the recovery rate and grade of silicon are maintained above 80%, and the separation efficiency is maintained above 70%.

Next, under the premise that the basic separation conditions remain unchanged and the target acid-base value is 5, the addition amount of sodium lauryl sulfate is changed. The purpose is to find out the combination of 4-methyl-2-pentanol and sodium lauryl sulfate, under which sodium lauryl sulfate addition amount, the silicon carbide recovery rate, silicon grade and silicon carbide The three separation efficiency can reach the highest.

Please refer to Figure 15. Figure 15 is the separation and extraction of the sample weight of the sample with different sodium dodecyl sulfate (SDS) added by 4-methyl-2-pentanol in the second embodiment of the present invention. Result graph. As the addition of sodium lauryl sulfate increases, the silicon carbide recovery rate and silicon grade increase, but the silicon carbide grade and silicon recovery rate decrease. This phenomenon means that as the addition of sodium lauryl sulfate increases, the silicon carbide grade decreases as the silicon recovery rate decreases. The reason is that as the addition amount of sodium lauryl sulfate increases, the silicon extracted to the 4-methyl-2-pentanol phase also increases, which results in a decrease in the silicon recovery rate and a decrease in the silicon carbide grade. When the addition amount of sodium lauryl sulfate is greater than 0.5 kg/ton relative to the sample weight of 1 ton, the recovery rate of silicon carbide is more than 93%. When the addition amount of sodium lauryl sulfate is 2.0 kg/ton relative to the sample weight of 1 ton, the silicon grade reaches the highest 97%.

It can be seen from the above that under the premise that the basic separation conditions remain unchanged and the target acid-base value is 5, the combination of 4-methyl-2-pentanol and sodium lauryl sulfate can be used in the addition of sodium lauryl sulfate. Relative to 1 ton of sample weight of 1.0 kg/ton, the silicon carbide recovery rate is 96.4%, the silicon carbide grade is 83.6%, the silicon recovery rate is 75.6%, the silicon grade is 96.5%, and the silicon carbide separation efficiency reaches The highest is 80.3%. When the addition amount of sodium lauryl sulfate is 2.0 kg/ton relative to the sample weight of 1 ton, the silicon carbide recovery rate is 98.3%, the silicon carbide grade is 80.7%, the silicon recovery rate is 70.1%, and the silicon grade At 97.0%, the silicon carbide separation efficiency reaches the highest 79.3%. Although the separation efficiency of silicon carbide is compared, the amount of sodium lauryl sulfate added relative to the sample weight of 1 ton is 2 kg/ton, which is significantly higher than the amount of sodium lauryl sulfate added relative to the sample weight of 1 ton is 1 kg /ton is slightly lower by 1%, but considering that in order to obtain high-recovery silicon carbide and high-grade silicon, 2 kg/ton is the optimal addition amount of sodium lauryl sulfate relative to the sample weight of 1 ton.

It is worth mentioning that under the premise that the basic separation conditions remain unchanged and the target acid-base value is 5, as long as the amount of sodium lauryl sulfate added relative to the sample weight of 1 ton is maintained at 0.25~2 kg/ ton, the recovery rate and grade of silicon carbide are maintained above 85%, the recovery rate of silicon is maintained above 70%, the grade of silicon is maintained above 80%, and the separation efficiency of silicon carbide is maintained above 75%.

The silicon carbide separation efficiency of the control group 1, the control group two, the experimental group two, the experimental group three, the first stage of the TW 201040109 patent case, and the second embodiment of the present invention are summarized in Table 2.

"Table II" Control group one Control group two Experimental group two Experimental group three TW 201040109 Embodiment 2 of the present invention Silicon carbide separation efficiency 38.3% 65.9% 64.7% 66.6% 63.98% 75% or more

From the comparison of the experimental results of the second embodiment of the present invention and the control group 1, it can be proved that the second embodiment of the present invention is in an environment with a target pH of 5 and the addition amount of sodium lauryl sulfate is relative to 1 The sample weight of ton is controlled at 0.25~2 kg/ton, etc., which can provide better capture effect of sodium lauryl sulfate on the silicon carbide contained in the mixed slurry, so that the separation efficiency of silicon carbide can be reduced from 38.3 % Increased significantly to over 75%, at least 36.7%.

If compared with the same stage, the silicon carbide separation efficiency of the first stage of the TW 201040109 patent case is 63.98% (recovery rate 83.1% multiplied by 77% grade multiplied by 100%), while the separation of the second embodiment of the present invention The silicon carbide separation efficiency in the first stage of the method is above 75%. It can be seen that the silicon carbide separation efficiency in the first stage of the method of the TW 201040109 patent is lower than the silicon carbide separation efficiency in the first stage of the separation method of the second embodiment of the present invention. This is why the TW 201040109 patent case must undergo the second stage of separation, and even the third stage of separation, to further increase the silicon carbide separation efficiency to be equal to or exceed the silicon carbide separation efficiency of the second embodiment of the present invention.

Furthermore, compared with the TW 201040109 patent case, the organic solvent selected in the second embodiment of the present invention is 4-methyl-2-pentanol, which is far less toxic than bromoform and is less harmful to the human body and the environment.

Comparing the experimental results of the control group two with the experimental group three, it can be proved that when the organic solvent is diesel oil, even if sodium lauryl sulfate is added, the separation efficiency of silicon carbide is not significantly improved.

From the comparison of the experimental results of the second embodiment of the present invention and the third experimental group, it can be proved that the second embodiment of the present invention is in an environment with a target pH of 5 and the addition amount of sodium lauryl sulfate is relative to 1 The sample weight of ton is controlled at 0.25~2 kg/ton, etc., which can provide the sodium lauryl sulfate to have a better trapping effect on the silicon carbide contained in the mixed slurry, plus a specific organic solvent: 4 -Methyl-2-pentanol, which can slightly increase the separation efficiency of silicon carbide from 66.6% to more than 75%, at least 8.4%.

According to the 2017 statistics of the Business Waste Declaration and Management Information System of the Environmental Protection Agency of the Executive Yuan, Taiwan's silicon wafer manufacturing industry generates approximately 16,577 metric tons of silicon wafer cutting waste each year. If the silicon carbide separation efficiency can be increased by 1%, a considerable amount of silicon carbide and silicon can be recycled every year in Taiwan alone. If applied to related industries around the world, the world's annual recycling of silicon carbide and silicon will be even more impressive.

In general, the silicon carbide separation efficiency of Example 2 of the present invention is more than 75%, which is greater than 38.3% of the control group 1, 65.9% of the control group 2 (ie, the document 1 described in the prior art), and the experimental group 2 64.7% of the total, 66.6% of the experimental group three, and 63.98% of the first phase of the TW 201040109 patent case. The reason is that: before adding sodium lauryl sulfate, the target pH value is controlled at 5, and the amount of sodium lauryl sulfate added relative to the weight of 1 ton of the sample is controlled at 0.25~2 kg/ton. Sodium alkyl sulfate can interact with silicon carbide powder in an appropriate pH environment to promote separation. At the same time, the applicable organic solvent is limited to 4-methyl-2-pentanol, which does not contain bromoform.

If the second embodiment of the present invention is extended to related industries all over the world, the annual recovery of silicon carbide and silicon in the world will far exceed those of the control group one, the control group two (ie, the document one described in the prior art) and the experimental group two The third experimental group and the first phase of the TW 201040109 patent case do not need to further carry out the second or even third phase, which can save huge costs and avoid the risk of environmental pollution by extremely toxic compounds such as bromoform.

Please refer to appendix 1. The addition amount of 2-methyl-2-pentanol to the sample of the second embodiment of the present invention to different sodium dodecyl sulfate (SDS) relative to the sample weight of 1 ton is between 0 ~2 kg/ton of separation and extraction result photos. Compared with the second limitation of Document 1 described in the prior art, the second embodiment of the present invention separates all silicon carbide into the oil phase, and the batch processing capacity is higher than that of Document 1 described in the prior art.

Even if the person with ordinary knowledge in the technical field of the invention, after referring to the TW 201040109 patent case and the document 1 described in the prior art, there is a reasonable motivation to think of all the steps of the separation method of the second embodiment of the present invention. The organic solvent is diesel oil. , And tried to add sodium lauryl sulfate, only the same results as the experimental group three can be obtained. It is absolutely impossible to think of all the technical features of the second embodiment of the present invention, let alone achieve the advantageous effects of the second embodiment of the present invention. Therefore, compared with the TW 201040109 patent case and the document 1 described in the prior art combined with common knowledge, the second embodiment of the present invention is more advanced.

In addition, the chemical structure of sodium tetradecyl sulfate, sodium laureth sulfate, sodium dodecyl sulfonate, sodium decayl sulfonate and sodium p-toluene sulfonate, and sodium lauryl sulfate The chemical properties are very similar and have similar effects. It can be substituted for sodium lauryl sulfate and obtain similar results as in Example 2.

Example 3: 4-methyl-2-pentanol was used as the organic phase, and the added collector was sodium oleate (NaOL). The basic separation conditions of the third embodiment of the present invention are approximately the same as those of the first embodiment of the present invention, except that the collector is sodium oleate (NaOL).

First, under the premise that the basic separation conditions remain unchanged and the amount of sodium oleate added is 1.0 kg/ton relative to the sample weight of 1 ton, the target pH value is changed. The purpose is to find out the combination of 4-methyl-2-pentanol and sodium oleate, under which target pH condition, the silicon carbide recovery rate, silicon grade and silicon carbide separation efficiency can reach the highest .

Please refer to Figure 16, Figure 16 is the 4-methyl-2-pentanol added sodium oleate (NaOL) in Example 3 of the present invention relative to 1 ton of sample weight of 1 kg/ton. The separation of values extracts the result graph. When the target acid-base value is between 3 and 5, the silicon carbide recovery rate increases as the target acid-base value increases, and the silicon recovery rate decreases as the target acid-base value increases. This phenomenon means that the silicon carbide content in the 4-methyl-2-pentanol phase recovery increases and the silicon content increases, the silicon content in the water phase recovery decreases and the silicon carbide content decreases, so that the silicon grade increases with the target acid The alkali number increased and rose, but the silicon carbide grade did not change significantly. When the target acid-base value is greater than 5, the silicon carbide recovery rate decreases, and the silicon carbide grade does not change significantly and remains above 77.7%; the silicon recovery rate does not change significantly and ranges from 84.% to 93.1%; the silicon grade is not obvious Change and maintain above 50%. This phenomenon means that the content of silicon carbide in the recovered 4-methyl-2-pentanol phase decreases and the content of silicon does not increase or decrease significantly, and the content of silicon in the recovered water phase does not increase or decrease and the content of silicon carbide increases. Both the silicon carbide grade and the silicon grade declined slightly. Especially when the target acid-base value is 5, the silicon carbide recovery rate reaches the highest 61%, the silicon grade reaches the highest 63.5%, and the silicon carbide separation efficiency reaches the highest 51.7%.

It can be seen from the above that under the premise that the basic separation conditions remain unchanged and the amount of sodium oleate added is 1.0 kg/ton relative to the sample weight of 1 ton, the combination of 4-methyl-2-pentanol and sodium oleate, Under the condition of the target acid-base value of 5, the silicon carbide recovery rate reached the highest 61%, the silicon grade reached the highest 63.5%, and the silicon carbide separation efficiency reached the highest 51.7%.

It is worth mentioning that under the premise that the basic separation conditions remain unchanged and the amount of sodium oleate added relative to the sample weight of 1 ton is 1.0 kg/ton, as long as the target pH value is controlled between 4~7 , The silicon carbide recovery rate is maintained above 50%, the silicon carbide grade is maintained above 80%, the silicon recovery rate is maintained above 85%, the silicon grade is maintained above 50%, and the silicon carbide separation efficiency is maintained above 45%.

Next, under the premise that the basic separation conditions remain unchanged and the target acid-base value is 5, the amount of sodium oleate added is changed. The purpose is to find out the combination of 4-methyl-2-pentanol and sodium oleate, under which sodium oleate addition, silicon carbide recovery rate, silicon grade and silicon carbide separation efficiency can be all three Reach the highest.

Please refer to Figure 17. Figure 17 is a graph showing the separation and extraction results of 4-methyl-2-pentanol in the third embodiment of the present invention for the addition of different sodium oleate (NaOL) to the sample weight of 1 ton. . With the increase in the amount of sodium oleate added, the silicon carbide recovery rate and silicon grade increase, and there is no significant change in the silicon carbide grade and silicon recovery rate. When the amount of sodium oleate added relative to the sample weight of 1 ton is greater than 5 kg/ton, the recovery rate of silicon carbide decreases. The reason is that the micelle phenomenon occurs when sodium oleate is added excessively, which reduces the extraction of silicon carbide; however, the grade of silicon carbide does not change significantly. However, the silicon grade increases or decreases as the silicon carbide recovery rate increases or decreases. The reason is that with the increase in the amount of sodium oleate added, the recovery rate of silicon carbide increases, and there is no significant change in the recovery rate of silicon, which leads to an increase in silicon grade. When the amount of sodium oleate added is 5 kg/ton relative to the sample weight of 1 ton, the silicon carbide recovery rate reaches the highest 90.7%, the silicon carbide grade reaches the highest 91.3%, and the silicon grade reaches the highest 88.3%.

It can be seen from the above that under the premise that the basic separation conditions remain unchanged and the target acid-base value is 5, the combination of 4-methyl-2-pentanol and sodium oleate is more than the amount of sodium oleate added to 1 ton. When the sample weight is 5 kg/ton, the recovery rate of silicon carbide reaches 90.7%, the silicon grade reaches 88.3%, and the separation efficiency of silicon carbide reaches 82.8%.

It is worth mentioning that under the premise that the basic separation conditions remain unchanged and the target acid-base value is 5, as long as the addition amount of sodium oleate is maintained at 4~6 kg/ton relative to the sample weight of 1 ton, silicon carbide Both the recovery rate and grade are maintained above 80%, the silicon recovery rate and silicon grade are maintained above 80%, and the silicon carbide separation efficiency is maintained above 70%.

The silicon carbide separation efficiency of the control group 1, the control group 2, the experimental group 4, the first stage of the TW 201040109 patent case, and the third embodiment of the present invention are summarized in Table 3 below.

"Table Three" Control group one Control group two Experimental group four TW 201040109 Embodiment 3 of the present invention Silicon carbide separation efficiency 38.3% 65.9% 49.7% 63.98% More than 70%

Comparing the experimental results of Example 3 of the present invention with that of the control group 1, it can be proved that Example 3 of the present invention is in an environment with a target pH of 5 and the addition amount of sodium oleate is relative to a sample of 1 ton. The weight is controlled at 4~6 kg/ton and other conditions, which can provide sodium oleate with a better capture effect on the silicon carbide contained in the mixed slurry, which can greatly increase the separation efficiency of silicon carbide from 38.3% to 70% Above, at least an increase of 31.7%.

If compared with the same stage, the silicon carbide separation efficiency of the first stage of the TW 201040109 patent case is 63.98% (the recovery rate is 83.1% times the grade 77% times 100%), while the separation of the third embodiment of the present invention The silicon carbide separation efficiency in the first stage of the method is above 70%. It can be seen that the silicon carbide separation efficiency in the first stage of the method of the TW 201040109 patent case is lower than the silicon carbide separation efficiency in the first stage of the separation method of the third embodiment of the present invention. This is why the TW 201040109 patent case must undergo the second stage of separation, or even the third stage of separation, to further improve the silicon carbide separation efficiency to be equal to or exceed the silicon carbide separation efficiency of the third embodiment of the present invention.

Furthermore, compared with the TW 201040109 patent case, the organic solvent selected in the third embodiment of the present invention is 4-methyl-2-pentanol, which is far less toxic than bromoform, and is less harmful to the human body and the environment.

Comparing the experimental results of the control group two with the experimental group four, it can be proved that when the organic solvent is diesel oil, adding sodium oleate, the silicon carbide separation efficiency is reduced by 16.2%.

Comparing the experimental results of the third embodiment of the present invention with the experimental group four, it can be proved that the third embodiment of the present invention is in an environment with a target pH of 5 and the addition amount of sodium oleate is relative to a sample of 1 ton. The weight is controlled at 4~6 kg/ton, etc., which can provide better capture effect of sodium oleate on the silicon carbide contained in the mixed slurry, which can greatly increase the separation efficiency of silicon carbide from 49.7% to 70% Above, at least an increase of 20.3%.

According to the 2017 statistics of the Business Waste Declaration and Management Information System of the Environmental Protection Agency of the Executive Yuan, Taiwan's silicon wafer manufacturing industry generates approximately 16,577 metric tons of silicon wafer cutting waste each year. If the silicon carbide separation efficiency can be increased by 1%, a considerable amount of silicon carbide and silicon can be recycled every year in Taiwan alone. If applied to related industries around the world, the world's annual recycling of silicon carbide and silicon will be even more impressive.

In general, the silicon carbide separation efficiency of the third embodiment of the present invention is more than 70%, which is greater than 38.3% of the control group one, 65.9% of the control group two (ie, the document one described in the prior art), and the experimental group four 49.7% of the total and 63.98% of the first phase of the TW 201040109 patent case. The reason is: before adding sodium oleate, first adjust the target pH to 5, and the amount of sodium oleate added relative to the sample weight of 1 ton is controlled at 4~6 kg/ton. Sodium oleate can be properly adjusted. The pH environment interacts with silicon carbide powder to promote separation, and the applicable organic solvent is limited to 4-methyl-2-pentanol without bromoform.

If the third embodiment of the present invention is extended to related industries all over the world, the world’s annual recovery of silicon carbide and silicon will far exceed those of the control group one, the control group two (ie, the document one described in the prior art), and the experimental group four. As with the first stage of the TW 201040109 patent case, there is no need to further carry out the second or even third stage, which can save huge costs and avoid the risk of environmental pollution by extremely toxic compounds such as bromoform.

In addition, compared with the second limitation of Document 1 described in the prior art, the third embodiment of the present invention separates all silicon carbide into the oil phase, and the batch processing capacity is higher than that of Document 1 described in the prior art.

Even if the person with ordinary knowledge in the technical field of the invention, after consulting the TW 201040109 patent case and the document 1 described in the prior art, there is a reasonable motivation to think of all the steps of the separation method of the third embodiment of the present invention. The organic solvent is diesel oil. , And trying to add sodium oleate, only the same results as the experimental group four can be obtained. It is absolutely impossible to think of all the technical features of the third embodiment of the present invention, let alone achieve the advantageous effects of the third embodiment of the present invention. Therefore, compared to the TW 201040109 patent case and the document 1 described in the prior art combined with common knowledge, the third embodiment of the present invention is more advanced.

Example 4: Using isooctane as the organic phase, and the added collector is dodecylamine acetate (DAA). The basic separation conditions of Example 4 of the present invention are approximately the same as Example 1 of the present invention, except that the organic solvent is isooctane. Hereinafter, the isooctane phase will be used as the organic solvent phase. In the following, the isooctane phase recovered material will be used to represent the solids recovered from the isooctane phase, and the silicon carbide recovery rate and grade refer to the silicon carbide recovery rate and grade of the isooctane phase recovered material respectively. In the following, the water phase reclaimed material will be used to represent the solid material recovered in the water phase. The silicon recovery rate and grade refer to the silicon recovery rate and grade of the water phase reclaimed material respectively. The following silicon carbide separation efficiency is the product of the silicon carbide recovery rate and grade in the isooctane phase recovery. The larger the value, the higher the silicon carbide recovery rate and the grade in the isooctane recovery phase. The better the separation effect of silicon in the recycle, it is an index indicating the degree of separation between silicon carbide and silicon.

First, under the premise that the basic separation conditions remain unchanged and the addition amount of dodecylamine acetate is 0.1 kg/ton relative to the sample weight of 1 ton, the target pH value is changed. The purpose is to find out the combination of isooctane and dodecylamine acetate, under which target pH conditions, the silicon carbide recovery rate, silicon grade and silicon carbide separation efficiency can reach the highest three.

Please refer to Figure 18, Figure 18 is the separation of the sample with different target acid-base values of isooctane added dodecylamine acetate (DAA) relative to 1 ton of sample weight of 0.1 kg/ton in the fourth embodiment of the present invention Extract the result graph. When the target acid-base value is between 3-9, the silicon carbide recovery rate and silicon grade increase with the increase of the target acid-base value. The silicon recovery rate does not change significantly and is between 70.8% and 93.7%, and the silicon carbide grade is between 74.2 ~86.1%. This phenomenon means that the content of silicon carbide in the isooctane phase recovery increases and the silicon content does not change significantly, and the silicon content in the water phase recovery does not change significantly and the silicon carbide content decreases, so that the silicon carbide grade and the silicon grade increase . Especially when the target acid-base value is 9, the silicon carbide recovery rate reaches the highest 90.4%, the silicon grade reaches the highest 87%, and the silicon carbide separation efficiency reaches the highest 77.8%. However, when the target acid-base value is greater than 9, the silicon carbide recovery rate decreases and the silicon recovery rate increases. This phenomenon means that the silicon carbide content in the isooctane phase recovery decreases and the silicon content decreases, the silicon content in the water phase recovery increases and the silicon carbide content increases, so that the silicon carbide grade does not change significantly, but the silicon grade decreases.

It can be seen from the above that under the premise that the basic separation conditions remain unchanged and the addition amount of dodecylamine acetate relative to the sample weight of 1 ton is 0.1 kg/ton, the combination of isooctane and dodecylamine acetate , Under the condition of the target acid-base value of 9, the silicon carbide recovery rate reaches the highest 90.4%, the silicon grade reaches the highest 87%, and the silicon carbide separation efficiency reaches the highest 77.8%.

It is worth mentioning that under the premise that the basic separation conditions remain unchanged and the addition amount of dodecylamine acetate relative to the sample weight of 1 ton is 0.1 kg/ton, as long as the target pH value is controlled between From 8.5 to 9.5, the recovery rate and grade of silicon carbide are maintained above 80%, the recovery rate and grade of silicon are maintained above 80%, and the separation efficiency of silicon carbide is maintained above 65%.

Next, under the premise that the basic separation conditions remain unchanged and the target acid-base value is 9, the addition amount of dodecylamine acetate is changed. The purpose is to find out the combination of isooctane and dodecylamine acetate, under which dodecylamine acetate addition amount, the silicon carbide recovery rate, silicon grade and silicon carbide separation efficiency are all Can reach the highest.

Please refer to FIG. 19, which is a graph showing the separation and extraction results of isooctane added to different dodecylamine acetate (DAA) samples relative to the weight of 1 ton of the sample. With the increase in the amount of dodecylamine acetate added, the recovery rate of silicon carbide decreases and the recovery rate of silicon decreases. The reason is that as the addition amount of dodecylamine acetate increases, the silicon carbide extracted to the isooctane phase decreases, and the silicon extracted to the isooctane phase increases, resulting in a decrease in both the silicon carbide grade and the silicon grade. . When the addition amount of dodecylamine acetate is 0.1 kg/ton relative to the sample weight of 1 ton, the silicon carbide recovery rate reaches the highest 90.4%, and the silicon grade reaches the highest 87%.

It can be seen from the above that under the premise that the basic separation conditions remain unchanged and the target acid-base value is 9, the combination of isooctane and dodecylamine acetate is relative to 1 ton of dodecylamine acetate. When the sample weight is 0.1 kg/ton, the silicon carbide recovery rate can reach up to 90.4%, the silicon grade can reach up to 87%, and the silicon carbide separation efficiency can reach up to 77.8%.

It is worth mentioning that under the premise that the basic separation conditions remain unchanged and the target acid-base value is 9, as long as the addition amount of dodecylamine acetate relative to the sample weight of 1 ton is maintained at 0.1~0.25 kg/ ton, silicon carbide recovery rate and grade are maintained above 80%, silicon recovery rate is maintained above 75%, silicon grade is maintained above 80%, and silicon carbide separation efficiency is maintained above 70%.

The silicon carbide separation efficiency of the control group 2, the experimental group 2, the experimental group 5, the first stage of the TW 201040109 patent case, and the fourth embodiment of the present invention are summarized in Table 4 below.

"Table Four" Control group two Experimental group two Experimental group five TW 201040109 Fourth embodiment of the present invention Silicon carbide separation efficiency 65.9% 64.7% 42.8% 63.98% More than 70%

From the comparison of the experimental results of the fourth embodiment of the present invention and the experimental group five, it can be proved that the experimental group five is in an environment with a target pH of 7 and the addition amount of sodium hexametaphosphate relative to the sample weight of 1 ton is 0.25 kg Under the condition of /ton, not only does it not help to increase the efficiency of silicon carbide separation, but it drops from more than 70% to 42.8%, which is a full drop of at least 27.2%. The reason is: Sodium hexametaphosphate only promotes the separation of silicon carbide and silicon particles in the mixed slurry, avoids sedimentation or agglomeration, and enables the particles to be dispersed to be stably dispersed in the medium. This effect is called dispersion. This is the characteristic of the dispersant, which is different from the trapping effect. Therefore, sodium hexametaphosphate is indeed a dispersant, not a collector, so it is not necessary to adjust the target pH in advance.

If compared with the same stage, the silicon carbide separation efficiency of the first stage of the TW 201040109 patent case is 63.98% (the recovery rate is 83.1% times the grade 77% times 100%), while the separation of the fourth embodiment of the present invention The silicon carbide separation efficiency in the first stage of the method is above 70%. It can be seen that the silicon carbide separation efficiency in the first stage of the method of the TW 201040109 patent case is lower than the silicon carbide separation efficiency in the first stage of the separation method of the fourth embodiment of the present invention. This is why the TW 201040109 patent case must undergo the second stage of separation, or even the third stage of separation, to further increase the silicon carbide separation efficiency to be equal to or exceed the silicon carbide separation efficiency of the fourth embodiment of the present invention.

Furthermore, compared with the TW 201040109 patent case, the organic solvent selected in the fourth embodiment of the present invention is isooctane, which is far less toxic than bromoform and is less harmful to the human body and the environment.

From the comparison of the experimental results of the fourth embodiment of the present invention with the experimental group two, it can be proved that the fourth embodiment of the present invention is in an environment with a target pH of 9 and the addition amount of dodecylamine acetate is relative to 1 The sample weight of ton is controlled at 0.1~0.25kg/ton, etc., which can provide dodecylamine acetate to have a better trapping effect on the silicon carbide contained in the mixed slurry, so that the silicon carbide separation efficiency can be increased from 64.7 % Increased slightly to more than 70%, at least 5.3%.

According to the 2017 statistics of the Business Waste Declaration and Management Information System of the Environmental Protection Agency of the Executive Yuan, Taiwan's silicon wafer manufacturing industry generates approximately 16,577 metric tons of silicon wafer cutting waste each year. If the silicon carbide separation efficiency can be increased by 1%, a considerable amount of silicon carbide and silicon can be recycled every year in Taiwan alone. If applied to related industries around the world, the world's annual recycling of silicon carbide and silicon will be even more impressive.

In general, the silicon carbide separation efficiency of the fourth embodiment of the present invention is more than 70%, which is greater than 65.9% of the control group two (ie, the document one described in the prior art), 64.7% of the experimental group two, and the experimental group five. 42.8% and 63.98% of the first phase of the TW 201040109 patent case. The reason is: before adding dodecylamine acetate, adjust the target acid-base value to 9. The amount of dodecylamine acetate added relative to the sample weight of 1 ton is controlled within 0.1~0.25 kg/ton. Alkylamine acetate can interact with silicon carbide powder in an appropriate pH environment to promote separation. At the same time, the applicable organic solvent is limited to isooctane and does not contain bromoform.

If the fourth embodiment of the present invention is extended to related industries all over the world, the world’s annual recovery of silicon carbide and silicon will far exceed those of the control group two (ie, the document one described in the prior art), the experimental group two, and the experimental group five. As with the first stage of the TW 201040109 patent case, there is no need to further carry out the second or even third stage, which can save huge costs and avoid the risk of environmental pollution by extremely toxic compounds such as bromoform.

In addition, compared with the second limitation of the document 1 described in the prior art, the fourth embodiment of the present invention separates all the silicon carbide into the oil phase, and the batch processing capacity is higher than that of the document 1 described in the prior art.

Even if the person with ordinary knowledge in the technical field of the invention, after consulting the TW 201040109 patent case and the document 1 described in the prior art, there is a reasonable motivation to think of all the steps of the separation method of the fourth embodiment of the present invention. The organic solvent is diesel oil. And trying to add dodecylamine acetate, only the same results as the experimental group two can be obtained. It is absolutely impossible to think of all the technical features of the fourth embodiment of the present invention, let alone achieve the beneficial effects of the fourth embodiment of the present invention. Therefore, compared with the TW 201040109 patent case and the document 1 described in the prior art combined with common knowledge, the fourth embodiment of the present invention is more advanced.

Example 5: Using isooctane as the organic phase, and the added collector is sodium oleate (NaOL). The basic separation conditions of the fifth embodiment of the present invention are approximately the same as those of the fourth embodiment of the present invention, except that the collector is sodium oleate (NaOL).

First, under the premise that the basic separation conditions remain unchanged and the amount of sodium oleate added is 0.1 kg/ton relative to the sample weight of 1 ton, the target pH value is changed. The purpose is to find out the combination of isooctane and sodium oleate, under which target pH conditions, the silicon carbide recovery rate, silicon grade and silicon carbide separation efficiency can reach the highest three.

Please refer to Figure 20. Figure 20 is the separation and extraction result curve of isooctane added sodium oleate (NaOL) relative to the sample weight of 1 ton of 0.1 kg/ton for the sample at different target pH values in the fifth embodiment of the present invention Figure. When the target acid-base value is between 3 and 5, the silicon carbide recovery rate increases as the target acid-base value increases, and the silicon recovery rate increases as the target acid-base value increases. This phenomenon means that the content of silicon carbide in the recovered isooctane phase increases and the content of silicon decreases, and the content of silicon in the recovered water phase increases and the content of silicon carbide decreases, thereby increasing the grade of silicon carbide and silicon. When the target acid-base value is greater than 5, the silicon carbide recovery rate decreases, while the silicon recovery rate does not change significantly and is between 76.2-90.9%. This phenomenon means that the content of silicon carbide in the recovered isooctane phase is reduced and there is no significant change in the silicon content, and the content of silicon in the recovered water phase does not change significantly and the content of silicon carbide increases, so that the silicon carbide grade and the silicon grade both decrease . Especially when the target acid-base value is 5, the silicon carbide recovery rate reaches the highest 85.7%, the silicon carbide grade reaches the highest 89.6%, the silicon grade reaches the highest 82.8%, and the silicon carbide separation efficiency reaches the highest 76.8%.

It can be seen from the above that under the premise that the basic separation conditions remain unchanged and the addition amount of sodium oleate is 0.1 kg/ton relative to the sample weight of 1 ton, the combination of isooctane and sodium oleate is at the target pH Under the condition of 5, the silicon carbide recovery rate reaches the highest 85.7%, the silicon grade reaches the highest 82.8%, and the silicon carbide separation efficiency reaches the highest 76.8%.

It is worth mentioning that under the premise that the basic separation conditions remain unchanged and the amount of sodium oleate added is 0.1 kg/ton relative to the sample weight of 1 ton, as long as the target pH value is controlled between 4.5 and 5.5 , Both the silicon carbide recovery rate and silicon grade are maintained above 80%, the silicon carbide grade and silicon recovery rate are maintained above 85%, and the silicon carbide separation efficiency is maintained above 65%.

Next, under the premise that the basic separation conditions remain unchanged and the target acid-base value is 5, the amount of sodium oleate added is changed. The purpose is to find out the combination of isooctane and sodium oleate, under which sodium oleate addition, the silicon carbide recovery rate, silicon grade and silicon carbide separation efficiency can reach the highest three.

Please refer to Figure 21. Figure 21 is a graph showing the separation and extraction results of isooctane to different sodium oleate (NaOL) addition amounts relative to 1 ton of sample weight in Example 5 of the present invention. When the addition amount of sodium oleate is 0.1~1.0 kg/ton relative to the sample weight of 1 ton, there is no significant change in the recovery rate and grade of silicon carbide, and there is no significant change in the recovery rate and grade of silicon. The recovery rate of silicon is 77.5. ~87.3%. When the amount of sodium oleate added relative to the sample weight of 1 ton is greater than 1.0 kg/ton, the recovery rate and grade of silicon carbide decrease. The reason is that the micelle phenomenon occurs when sodium oleate is added excessively, which reduces the extraction of silicon carbide. In addition, when the amount of sodium oleate added relative to the sample weight of 1 ton is greater than 1.0 kg/ton, the silicon recovery rate does not change significantly, and the silicon grade decreases. However, the silicon grade increases or decreases as the silicon carbide recovery rate increases or decreases. The reason is that with the increase in the amount of sodium oleate added, the recovery rate of silicon carbide decreases, and there is no significant change in the recovery rate of silicon, which leads to a decrease in silicon grade. Especially when the added amount of sodium oleate is 1.0 kg/ton relative to the sample weight of 1 ton, the silicon carbide recovery rate reaches the highest 91.1%, and the silicon grade reaches the highest 88.2%.

It can be seen from the above that under the premise that the basic separation conditions remain unchanged and the target pH value is 5, the combination of isooctane and sodium oleate is 1.0 kg relative to the sample weight of 1 ton. Under the condition of /ton, the maximum recovery rate of silicon carbide is 91.1%, the maximum silicon grade is 88.2%, and the maximum separation efficiency of silicon carbide is 80.3%.

It is worth mentioning that under the premise that the basic separation conditions remain unchanged and the target acid-base value is 5, as long as the addition amount of sodium oleate is maintained at 0.1~1.25 kg/ton relative to the sample weight of 1 ton, silicon carbide The recovery rate and grade are maintained above 85%, the silicon recovery rate is maintained above 75%, the silicon grade is maintained above 80%, and the silicon carbide separation efficiency is maintained above 70%.

The silicon carbide separation efficiency of the control group two, the experimental group four, the first stage of the TW 201040109 patent case, and the fifth embodiment of the present invention are summarized in Table 5.

"Table Five" Control group two Experimental group four TW 201040109 Embodiment 5 of the present invention Silicon carbide separation efficiency 65.9% 49.7% 63.98% More than 70%

If compared with the same stage, the silicon carbide separation efficiency of the first stage of the TW 201040109 patent case is 63.98% (recovery rate 83.1% multiplied by 77% grade multiplied by 100%), while the separation of the fifth embodiment of the present invention The silicon carbide separation efficiency in the first stage of the method is above 70%. It can be seen that the silicon carbide separation efficiency in the first stage of the method of the TW 201040109 patent is lower than the silicon carbide separation efficiency in the first stage of the separation method of the fifth embodiment of the present invention. This is why the TW 201040109 patent case must undergo the second stage of separation, and even the third stage of separation, in order to further increase the silicon carbide separation efficiency to be equal to or exceed the silicon carbide separation efficiency of the fifth embodiment of the present invention.

Furthermore, compared with the TW 201040109 patent case, the organic solvent selected in the fifth embodiment of the present invention is isooctane, which has much lower toxicity than bromoform and is less harmful to the human body and the environment.

From the comparison of the experimental results of the fifth embodiment of the present invention and the experimental group four, it can be proved that the fifth embodiment of the present invention is in an environment with a target pH of 5 and the addition amount of sodium oleate is relative to a sample of 1 ton The weight is controlled at 0.1~1.25kg/ton, etc., which can provide a better capture effect of sodium oleate on the silicon carbide contained in the mixed slurry, which can greatly increase the silicon carbide separation efficiency from 49.7% to 70% Above, at least an increase of 20.3%.

According to the 2017 statistics of the Business Waste Declaration and Management Information System of the Environmental Protection Agency of the Executive Yuan, Taiwan's silicon wafer manufacturing industry generates approximately 16,577 metric tons of silicon wafer cutting waste each year. If the silicon carbide separation efficiency can be increased by 1%, a considerable amount of silicon carbide and silicon can be recycled every year in Taiwan alone. If applied to related industries around the world, the world's annual recycling of silicon carbide and silicon will be even more impressive.

In general, the silicon carbide separation efficiency of Example 5 of the present invention is more than 70%, which is greater than 65.9% of the control group 2 (ie, the document 1 described in the prior art), 49.7% of the experimental group 4, and TW 201040109 patent. 63.98% of the first stage of the case. The reason is: before adding sodium oleate, first adjust the target pH to 5, the amount of sodium oleate added relative to the sample weight of 1 ton is controlled within 0.1~1.25 kg/ton, sodium oleate can be properly adjusted The pH environment interacts with silicon carbide powder to promote separation, and the applicable organic solvent is limited to isooctane and does not contain bromoform.

If the fifth embodiment of the present invention is extended to related industries all over the world, the world’s annual recovery of silicon carbide and silicon will far exceed those of the control group two (ie, the document one described in the prior art), the experimental group four and the TW 201040109 patent In the first stage of the case, there is no need to further carry out the second or even the third stage, which can save huge costs and avoid the risk of environmental pollution by extremely toxic compounds such as bromoform.

In addition, compared to the second limitation of the document 1 described in the prior art, the fifth embodiment of the present invention separates all the silicon carbide into the oil phase, and the batch processing capacity is higher than that of the document 1 described in the prior art.

Even if the person with ordinary knowledge in the technical field of the invention, after referring to the TW 201040109 patent case and the document 1 described in the prior art, there is a reasonable motivation to think of all the steps of the separation method of the fifth embodiment of the present invention. The organic solvent is diesel oil. , And trying to add sodium oleate, only the same results as the experimental group four can be obtained. It is absolutely impossible to think of all the technical features of the fifth embodiment of the present invention, let alone achieve the advantageous effects of the fifth embodiment of the present invention. Therefore, compared with the TW 201040109 patent case and the document 1 described in the prior art combined with common knowledge, the fifth embodiment of the present invention is more advanced.

Embodiments 1 to 5 of the present invention have common special technical features: (1) the step of adjusting the target acid-base value is performed first, and then the trapping step; and (2) the selection of organic solvents that can improve the trapping effect. The common special technical feature (1) enables the trapping agent to interact with silicon carbide in an appropriate pH environment to promote separation. The common special technical feature (2) can further improve the separation efficiency of silicon carbide. Therefore, the silicon carbide separation efficiency of Examples 1 to 5 of the present invention can all be above 70%. In the case that the common special technical features (1) and (2) are more advanced than the TW 201040109 patent case and the document 1 described in the prior art in combination with common knowledge, the first to fifth embodiments of the present invention have the unity of invention.

It should be noted that the surface of silicon carbide is positively charged when the target pH is less than 3.7, the surface of silicon carbide is negatively charged when the target pH is greater than 3.7, and the surface of silicon is negatively charged when the target pH is greater than 1.6 . Therefore, in all the above-mentioned embodiments, when the target acid-base value is 3, silicon carbide and silicon undergo heterogeneous agglomeration, and the silicon carbide with larger particles is covered by the silicon with smaller particles, making the silicon carbide and dodecylamine The combination of acetate, sodium lauryl or sodium oleate is hindered, resulting in a decrease in the recovery rate of silicon carbide in the recovered 4-methyl-2-pentanol phase or the isooctane phase.

To summarize the above, in all the examples, based on the second example of the present invention under the premise that the basic separation conditions remain unchanged and the target acid-base value is 5, 4-methyl-2-pentanol and sodium lauryl sulfate Under the condition that the addition amount of sodium lauryl sulfate is 2.0 kg/ton relative to the sample weight of 1 ton, the best separation effect is obtained: the recovery rate of silicon carbide is 98.3%, and the silicon grade is 97.0% , The separation efficiency of silicon carbide reaches the highest 79.3%. Therefore, the following will further discuss the particle size analysis of the recovered 4-methyl-2-pentanol phase and the water phase after separation and extraction with the best separation result of Example 2 of the present invention.

Please refer to FIG. 22, which is a schematic diagram of the particle size analysis result of the recovered 4-methyl-2-pentanol phase under the optimal separation conditions in the second embodiment of the present invention. The average particle size of the recovered 4-methyl-2-pentanol phase is 9.80 μm, and a small number of particles with a particle size of about 0.2~0.4 μm are estimated to be extracted to the 4-methyl-2-pentanol phase Silicon carbide and a small part are drawn out together.

Please refer to FIG. 23. FIG. 23 is a schematic diagram of the particle size analysis result of the water phase reclaimed product under the optimal separation conditions in the second embodiment of the present invention. The average particle size of the recovered water phase is 0.39 μm and some particles larger than 1 μm are presumed to be silicon staying in the water phase and a small amount of silicon carbide extracted.

Please refer to FIG. 24. FIG. 24 is a schematic diagram of the structural appearance analysis result of the 4-methyl-2-pentanol phase recovered under the optimal separation conditions in the second embodiment of the present invention using a scanning electron microscope. The particles with obvious edges and corners are silicon carbide, and the small particles are silicon. Compared with the structural appearance of the sample shown in Fig. 4, in Example 2 of the present invention, the amount of small silicon particles in the structural appearance of the 4-methyl-2-pentanol phase recovered under the optimal separation conditions is reduced, which represents the extraction to Most of the particles in the 4-methyl-2-pentanol phase are silicon carbide.

The following will take Example 2 of the present invention as an example to adjust the addition amount of organic solvent and deionized water in the separation conditions, and set the separation conditions at the target acid-base value of 5, and the addition amount of sodium lauryl sulfate as 2.0 kg/ton, further discuss the volume ratio of organic solvent phase and water phase. As shown in Figure 25, when the volume ratio of 4-methyl-2-pentanol and water is 1:9 to 1:4 (that is, 10 ml: 90 ml to 20 ml: 80 ml), the recovery rate of silicon carbide and silicon The grade increases as the volume ratio of 4-methyl-2-pentanol to water increases. Especially when the volume ratio of 4-methyl-2-pentanol to water is 1:4, the recovery rate of silicon carbide reaches the highest 98.3%, the silicon carbide grade reaches the highest 80.7%, and the silicon grade reaches the highest 97%. When the volume ratio of 4-methyl-2-pentanol to water is greater than 1:4, the silicon carbide recovery rate and silicon grade will decrease as the volume ratio of 4-methyl-2-pentanol to water increases, and the silicon carbide grade And the silicon recovery rate did not change significantly. This phenomenon means that as the volume ratio of 4-methyl-2-pentanol to water increases, the silicon carbide pumped into the 4-methyl-2-pentanol phase decreases, resulting in a decrease in the recovery rate of silicon carbide and the silicon grade. The first embodiment of the present invention and the third embodiment of the present invention have similar results, so they will not be discussed separately.

The following will take Example 2 of the present invention as an example, adjust the sample weight in the separation conditions, and set the separation conditions at the target acid-base value of 5, and the addition amount of sodium lauryl sulfate relative to the sample weight of 1 ton is 2.0 kg/ton, the rest of the separation conditions remain unchanged, further discuss the solid-liquid ratio. As shown in Figure 26, the solid-to-liquid ratio between the weight of the sample (in g) and the volume of the liquid composed of water and 4-methyl-2-pentanol (in ml) ranges from 1:50 to 3:50 (Ie, 2 g/100 ml to 6 g/100 ml), there is no significant change in the recovery rate and grade of silicon carbide. When the solid-liquid ratio is between 1:50 and 1:25 (ie, 2 g/100 ml to 4 g/100 ml), the silicon recovery rate and grade will decrease as the solid-liquid ratio increases. When the solid-liquid ratio is greater than 1:25, the silicon recovery rate increases slightly with the increase of the solid-liquid ratio, and the silicon grade and silicon carbide separation efficiency both decrease with the increase of the solid-liquid ratio. When the solid-liquid ratio is 2:25 (ie, 8 g/100 ml), the silicon carbide recovery rate drops to 44.3%, the silicon carbide grade drops to 63.5%, and the silicon grade drops to 48.8%. Therefore, when the solid-liquid ratio is greater than 3:50 (ie, 6 g/100 ml), the expected separation effect cannot be achieved. Especially when the solid-liquid ratio is 1:50 (ie, 2 g/100 ml), the silicon carbide recovery rate reaches the highest 98.3%, the silicon carbide grade reaches the highest 80.7%, the silicon recovery rate reaches the highest 70.1%, and the silicon grade reaches the highest 97%.

In summary, the present invention can remove silicon carbide and silicon in silicon wafer cutting waste by using a less toxic organic solvent, and by first adjusting the target acid-base value, and then adding a trapping agent to make the silicon carbide Separation from silicon can be achieved in one separation operation procedure, and high-recovery silicon carbide and high-grade silicon can be obtained under optimal separation conditions, and the separation efficiency of silicon carbide is more than 70%, and it can also separate particles below 10 μm. , And then achieve the goal of reducing waste costs in the production of solar cells and achieving circular economy.

Furthermore, compared with the second limitation of Document 1 described in the prior art, the present invention separates all silicon carbide into the oil phase, and the batch processing capacity is higher than that of Document 1 described in the prior art.

The above descriptions are only used to explain the preferred embodiments of the present invention, and are not intended to limit the present invention in any form. Therefore, any modification or change related to the present invention made under the same inventive spirit , Should still be included in the scope of the present invention.

Attachment 1: Attachment 1 is the addition amount of 2-methyl-2-pentanol to the sample of the second embodiment of the present invention to different sodium dodecyl sulphate (SDS) relative to the sample weight of 1 ton between 0~2 The separation of kg/ton extracts the result photos.

S10: Pre-processing steps S20: Dispersion step S30: pH adjustment steps S40: Capture step S50: mixing steps S60: standing step S70: Centrifugation step S80: drying step

Figure 1 is a flowchart of the present invention. Fig. 2 is a schematic diagram of the particle size analysis result of the sample in the pretreatment step of the present invention by using a laser particle size analyzer. FIG. 3 is a schematic diagram of the crystal structure analysis result of the sample in the pretreatment step of the present invention by using an X-ray diffractometer. FIG. 4 is a schematic diagram of the structural appearance analysis result of the sample in the pretreatment step of the present invention by using a scanning electron microscope. Fig. 5 is a graph showing the separation and extraction results of samples at different target acid-base values of 4-methyl-2-pentanol without the addition of trapping agent in control group 1. Fig. 6 is a graph showing the separation and extraction results of the diesel oil of the control group 2 without the addition of the trapping agent at different target pH values. Figure 7 is the separation and extraction result curve of the sample with different target pH values for the sample weight of 1 ton of 4-methyl-2-pentanol added with sodium hexametaphosphate (dispersant) relative to 1 ton of 0.25 kg/ton. Figure. Fig. 8 is a graph showing the separation and extraction results of samples with different target acid-base values for the sample weight of 1 ton of dodecylamine acetate (DAA) relative to 1 ton of 0.25 kg/ton. Figure 9 is a graph showing the separation and extraction results of samples with different target acid-base values for the sample weight of 0.25 kg/ton relative to 1 ton of diesel fuel added with sodium dodecyl sulfate (SDS). Figure 10 is a graph showing the separation and extraction results of sodium oleate (NaOL) for diesel fuel in experimental group four relative to the sample weight of 1 ton of 0.25 kg/ton for different target acid-base values. Figure 11 is a graph showing the separation and extraction results of samples with different target acid-base values for the sample weight of 0.25 kg/ton relative to 1 ton of isooctane added sodium hexametaphosphate (dispersant) in experimental group 5. Fig. 12 is the comparison of 4-methyl-2-pentanol with dodecylamine acetate (DAA) relative to 1 ton of sample weight of 0.25 kg/ton relative to the sample at different target pH values in the first embodiment of the present invention. Separate and extract the result graph. FIG. 13 is a graph showing the separation and extraction results of the amount of 4-methyl-2-pentanol added to the sample to different dodecylamine acetate (DAA) relative to the weight of 1 ton of the sample in Example 1 of the present invention. Figure 14 shows the effect of adding sodium dodecyl sulfate (SDS) to 4-methyl-2-pentanol in Example 2 of the present invention relative to the sample weight of 1 ton of 0.25 kg/ton for samples at different target pH values Separate and extract the result graph. Fig. 15 is a graph showing the separation and extraction results of 4-methyl-2-pentanol in the second embodiment of the present invention with respect to the amount of sodium dodecyl sulfate (SDS) added to the sample relative to the sample weight of 1 ton. Figure 16 shows the separation and extraction results of samples with different target pH values for the sample weight of 1 kg/ton relative to the sample weight of 1 ton of 4-methyl-2-pentanol added with sodium oleate (NaOL) in Example 3 of the present invention Graph. Fig. 17 is a graph showing the separation and extraction results of 4-methyl-2-pentanol to the sample of different sodium oleate (NaOL) relative to the weight of 1 ton of the sample. 18 is a graph showing the separation and extraction results of samples with different target acid-base values of isooctane dodecylamine acetate (DAA) relative to 1 ton of sample weight of 0.1 kg/ton relative to the sample weight in Example 4 of the present invention. Fig. 19 is a graph showing the separation and extraction results of the isooctane of the present invention on different dodecylamine acetate (DAA) addition amounts relative to the sample weight of 1 ton. 20 is a graph showing the separation and extraction results of samples with different target acid-base values of 0.1 kg/ton relative to 1 ton of sample weight of isooctane added sodium oleate (NaOL) in Example 5 of the present invention. 21 is a graph showing the separation and extraction results of isooctane added to different sodium oleate (NaOL) samples relative to 1 ton of sample weight in Example 5 of the present invention. 22 is a schematic diagram of the particle size analysis results of the recovered 4-methyl-2-pentanol phase under the optimal separation conditions in Example 2 of the present invention. Figure 23 is a schematic diagram of the particle size analysis results of the water phase reclaimed product under the optimal separation conditions in the second embodiment of the present invention. FIG. 24 is a schematic diagram of the structural appearance analysis result of the 4-methyl-2-pentanol phase recovered under the optimal separation conditions of the second embodiment of the present invention using a scanning electron microscope. Figure 25 shows the sample weight of 2.0 kg/ton relative to 1 ton of 4-methyl-2-pentanol added with sodium dodecyl sulfate (SDS) in the second embodiment of the present invention. A graph of the separation and extraction results of the phase volume ratio. Figure 26 shows the separation of samples with different solid-to-liquid ratios by adding sodium dodecyl sulfate (SDS) to a sample weight of 2.0 kg/ton relative to 1 ton of 4-methyl-2-pentanol in Example 2 of the present invention Extract the result graph.

S10: Pre-processing steps

S20: Dispersion step

S30: pH adjustment steps

S40: Capture step

S50: mixing steps

S60: standing step

S70: Centrifugation step

S80: drying step

Claims (10)

A method for separating silicon carbide and silicon, including the following steps: Pre-processing steps: remove water, cutting oil and metal impurities in a silicon wafer cutting waste obtained by cutting a silicon crystal rod to obtain a sample composed of silicon carbide and silicon; Dispersion step: adding water to the sample and mixing it to form a mixed slurry, using an ultrasonic disperser to disperse the silicon carbide and silicon in the mixed slurry; PH adjusting step: adding an acid adjusting agent or an alkaline adjusting agent to a pH adjusting agent to adjust the pH of the mixed slurry to a target pH of 7; The trapping step: adding a trapping agent to capture the silicon carbide contained in the mixed slurry, wherein the trapping agent is Dodecylamine Acetate (DAA). The dosage of the agent is 0.2~0.5 kg/ton relative to the weight of 1 ton of the sample; Mixing step: use the shaking force generated by a shaker to perform a preliminary mixing of the mixed slurry, add an organic solvent, and use the shaker to perform an advanced mixing to form a mixed solution, wherein the organic solvent is 4-methyl-2-pentanol, the volume ratio of the organic solvent to water is between 1:9 to 1:4, the weight of the sample (in g) and the volume of the liquid composed of water and organic solvent (in The solid-liquid ratio of ml) is between 1:50 to 3:50; Standing step: the mixed solution is allowed to stand for a period of time to form an organic solvent phase solution and an aqueous phase solution that are separated from each other up and down, and then take out the organic solvent phase solution and the aqueous phase solution respectively, wherein the organic solvent phase solution Rich in silicon carbide, the aqueous solution is rich in silicon; Centrifugation step: use the centrifugal force generated by a centrifuge to separate the solids and liquids of the organic solvent phase solution, and take out the solids of the organic solvent phase solution, and use the centrifugal force generated by a centrifuge to separate the aqueous phase solution The solids and liquids are separated, and the solids of the aqueous solution are taken out; and Drying step: using a dryer to heat the solids of the organic solvent phase solution or the solids of the aqueous phase solution to remove the remaining liquid, thereby obtaining silicon carbide and silicon, respectively. The method for separating silicon carbide and silicon as described in item 1 of the scope of patent application, wherein the addition amount of the collector is 0.25 kg/ton relative to the sample weight of 1 ton, and the volume ratio of the organic solvent and water is 1 : 4. The solid-liquid ratio of the weight of the sample (unit: g) to the volume (unit: ml) of the liquid composed of water and organic solvent is 1:50. A method for separating silicon carbide and silicon, including the following steps: Pre-processing steps: remove water, cutting oil and metal impurities in a silicon wafer cutting waste obtained by cutting a silicon crystal rod to obtain a sample composed of silicon carbide and silicon; Dispersion step: adding water to the sample and mixing it to form a mixed slurry, using an ultrasonic disperser to disperse the silicon carbide and silicon in the mixed slurry; PH adjustment step: adding an acid regulator or a pH regulator of an alkali regulator to adjust the pH of the mixed slurry to a target pH of 5; The trapping step: adding a trapping agent to capture the silicon carbide contained in the mixed slurry, wherein the trapping agent is selected from sodium dodecyl sulfate (SDS), Sodium Tetradecyl Sulfate (Sodium Tetradecyl Sulfate), Sodium Laureth Sulfate (Sodium Laureth Sulfate), Sodium Dodecyl Sulfonate (Sodium Dodecyl Sulfonate), Sodium Decane-1 -Sulfonate) and sodium p-Toluene Sulfonate (Sodium p-Toluene Sulfonate) in one of the group, the addition amount of the collector is between 0.25~2 kg/ton relative to the sample weight of 1 ton; Mixing step: use the shaking force generated by a shaker to perform a preliminary mixing of the mixed slurry, add an organic solvent, and use the shaker to perform an advanced mixing to form a mixed solution, wherein the organic solvent is 4-methyl-2-pentanol, the volume ratio of the organic solvent to water is between 1:9 to 1:4, the weight of the sample (in g) and the volume of the liquid composed of water and organic solvent (in The solid-liquid ratio of ml) is between 1:50 to 3:50; Standing step: the mixed solution is allowed to stand for a period of time to form an organic solvent phase solution and an aqueous phase solution that are separated from each other up and down, and then take out the organic solvent phase solution and the aqueous phase solution respectively, wherein the organic solvent phase solution Rich in silicon carbide, the aqueous solution is rich in silicon; Centrifugation step: use the centrifugal force generated by a centrifuge to separate the solids and liquids of the organic solvent phase solution, and take out the solids of the organic solvent phase solution, and use the centrifugal force generated by a centrifuge to separate the aqueous phase solution The solids and liquids are separated, and the solids of the aqueous solution are taken out; and Drying step: using a dryer to heat the solids of the organic solvent phase solution or the solids of the aqueous phase solution to remove the remaining liquid, thereby obtaining silicon carbide and silicon, respectively. The method for separating silicon carbide and silicon as described in item 3 of the scope of patent application, wherein the additive amount of the collector is 2 kg/ton relative to the weight of 1 ton of the sample, and the volume ratio of the organic solvent to water is 1 : 4. The solid-liquid ratio of the weight of the sample (unit: g) to the volume (unit: ml) of the liquid composed of water and organic solvent is 1:50. A method for separating silicon carbide and silicon, including the following steps: Pre-processing steps: remove water, cutting oil and metal impurities in a silicon wafer cutting waste obtained by cutting a silicon crystal rod to obtain a sample composed of silicon carbide and silicon; Dispersion step: adding water to the sample and mixing it to form a mixed slurry, using an ultrasonic disperser to disperse the silicon carbide and silicon in the mixed slurry; PH adjustment step: adding an acid regulator or a pH regulator of an alkali regulator to adjust the pH of the mixed slurry to a target pH of 5; The trapping step: add a trapping agent to capture the silicon carbide contained in the mixed slurry, wherein the trapping agent is sodium oleate (NaOL), the addition of the trapping agent Relative to the sample weight of 1 ton, between 4~6 kg/ton; Mixing step: use the shaking force generated by a shaker to perform a preliminary mixing of the mixed slurry, add an organic solvent, and use the shaker to perform an advanced mixing to form a mixed solution, wherein the organic solvent is 4-methyl-2-pentanol, the volume ratio of the organic solvent to water is between 1:9 to 1:4, the weight of the sample (in g) and the volume of the liquid composed of water and organic solvent (in The solid-liquid ratio of ml) is between 1:50 to 3:50; Standing step: the mixed solution is allowed to stand for a period of time to form an organic solvent phase solution and an aqueous phase solution that are separated from each other up and down, and then take out the organic solvent phase solution and the aqueous phase solution respectively, wherein the organic solvent phase solution Rich in silicon carbide, the aqueous solution is rich in silicon; Centrifugation step: use the centrifugal force generated by a centrifuge to separate the solids and liquids of the organic solvent phase solution, and take out the solids of the organic solvent phase solution, and use the centrifugal force generated by a centrifuge to separate the aqueous phase solution The solids and liquids are separated, and the solids of the aqueous solution are taken out; and Drying step: using a dryer to heat the solids of the organic solvent phase solution or the solids of the aqueous phase solution to remove the remaining liquid, thereby obtaining silicon carbide and silicon, respectively. The method for separating silicon carbide and silicon as described in item 5 of the scope of patent application, wherein the additive amount of the collector is 5 kg/ton relative to the sample weight of 1 ton, and the volume ratio of the organic solvent to water is 1 : 4. The solid-liquid ratio of the weight of the sample (unit: g) to the volume (unit: ml) of the liquid composed of water and organic solvent is 1:50. A method for separating silicon carbide and silicon, including the following steps: Pre-processing steps: remove water, cutting oil and metal impurities in a silicon wafer cutting waste obtained by cutting a silicon crystal rod to obtain a sample composed of silicon carbide and silicon; Dispersion step: adding water to the sample and mixing it to form a mixed slurry, using an ultrasonic disperser to disperse the silicon carbide and silicon in the mixed slurry; PH adjustment step: adding an acid regulator or a pH regulator of an alkali regulator to adjust the pH of the mixed slurry to a target pH of 9; The trapping step: adding a trapping agent to capture the silicon carbide contained in the mixed slurry, wherein the trapping agent is Dodecylamine Acetate (DAA). The dosage of the agent is 0.1~0.25 kg/ton relative to the weight of 1 ton of the sample; Mixing step: use the shaking force generated by a shaker to perform a preliminary mixing of the mixed slurry, add an organic solvent, and use the shaker to perform an advanced mixing to form a mixed solution, wherein the organic solvent is Isooctane, the volume ratio of the organic solvent and water is between 1:9 to 1:4, the weight of the sample (in g) and the volume of the liquid composed of water and organic solvent (in ml) are solid-liquid The ratio is between 1:50 to 3:50; Standing step: the mixed solution is allowed to stand for a period of time to form an organic solvent phase solution and an aqueous phase solution that are separated from each other up and down, and then take out the organic solvent phase solution and the aqueous phase solution respectively, wherein the organic solvent phase solution Rich in silicon carbide, the aqueous solution is rich in silicon; Centrifugation step: use the centrifugal force generated by a centrifuge to separate the solids and liquids of the organic solvent phase solution, and take out the solids of the organic solvent phase solution, and use the centrifugal force generated by a centrifuge to separate the aqueous phase solution The solids and liquids are separated, and the solids of the aqueous solution are taken out; and Drying step: using a dryer to heat the solids of the organic solvent phase solution or the solids of the aqueous phase solution to remove the remaining liquid, thereby obtaining silicon carbide and silicon, respectively. The method for separating silicon carbide and silicon as described in item 7 of the scope of patent application, wherein the addition amount of the collector is 0.1 kg/ton relative to the sample weight of 1 ton, and the volume ratio of the organic solvent to water is 1 : 4. The solid-liquid ratio of the weight of the sample (unit: g) to the volume (unit: ml) of the liquid composed of water and organic solvent is 1:50. A method for separating silicon carbide and silicon, including the following steps: Pre-processing steps: remove water, cutting oil and metal impurities in a silicon wafer cutting waste obtained by cutting a silicon crystal rod to obtain a sample composed of silicon carbide and silicon; Dispersion step: adding water to the sample and mixing it to form a mixed slurry, using an ultrasonic disperser to disperse silicon carbide and silicon in the mixed slurry; PH adjustment step: adding an acid regulator or a pH regulator of an alkali regulator to adjust the pH of the mixed slurry to a target pH of 5; The trapping step: add a trapping agent to capture the silicon carbide contained in the mixed slurry, wherein the trapping agent is sodium oleate (NaOL), the addition of the trapping agent The amount relative to the sample weight of 1 ton is between 0.1~1.25 kg/ton; Mixing step: use the shaking force generated by a shaker to perform a preliminary mixing of the mixed slurry, add an organic solvent, and use the shaker to perform an advanced mixing to form a mixed solution, wherein the organic solvent is Isooctane, the volume ratio of the organic solvent and water is between 1:9 to 1:4, the weight of the sample (in g) and the volume of the liquid composed of water and organic solvent (in ml) are solid-liquid The ratio is between 1:50 to 3:50; Standing step: the mixed solution is allowed to stand for a period of time to form an organic solvent phase solution and an aqueous phase solution that are separated from each other up and down, and then take out the organic solvent phase solution and the aqueous phase solution respectively, wherein the organic solvent phase solution Rich in silicon carbide, the aqueous solution is rich in silicon; Centrifugation step: use the centrifugal force generated by a centrifuge to separate the solids and liquids of the organic solvent phase solution, and take out the solids of the organic solvent phase solution, and use the centrifugal force generated by a centrifuge to separate the aqueous phase solution The solids and liquids are separated, and the solids of the aqueous solution are taken out; and Drying step: using a dryer to heat the solids of the organic solvent phase solution or the solids of the aqueous phase solution to remove the remaining liquid, thereby obtaining silicon carbide and silicon, respectively. The method for separating silicon carbide and silicon as described in item 9 of the scope of patent application, wherein the addition amount of the collector is 1.0 kg/ton relative to the sample weight of 1 ton, and the volume ratio of the organic solvent to water is 1 : 4. The solid-liquid ratio of the weight of the sample (unit: g) to the volume (unit: ml) of the liquid composed of water and organic solvent is 1:50.

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