A method for precipitating and separating silicon powder particles

Abstract

The present invention provides a method for precipitating and separating silicon powder particles. The steps include: preparing a coagulation-induced solution; mixing the prepared coagulation-induced solution with the cut coolant for precipitation, so that the silicon powder flocculates and separates from the original coolant. Among them, the coagulation-induced solution is used to induce the flocculation of the silicon powder. The present invention provides a method for precipitating and separating silicon powder particles. By inducing the flocculation of micron-sized silicon powder particles in the original coolant, the silicon powder can be quickly precipitated, so that the silicon powder particles are separated from the original coolant. The operation is simple, the cost is low, it is easy to control, and the separation effect is good.

Description

Technical Field

[0001] The invention belongs to the technical field of silicon wafer processing, and in particular relates to a silicon powder particle precipitation and separation method. Background Art

[0002] At present, the separation of silicon powder in the cooling waste liquid during cutting mainly adopts the conventional filter press filtration method to remove silicon powder. Although the filter press is simple to filter silicon powder, the processing capacity is limited and the efficiency is low. Especially at the end of the filtration process, the processing capacity is significantly reduced, and it is difficult to meet the demand for increased production capacity. Higher processing capacity also requires a higher power filter press, and the filter press equipment occupies an increased area. Therefore, how to propose a low-cost, non-toxic reagent, and high-efficiency silicon powder separation method is a technical problem that needs to be solved in existing production. Summary of the invention

[0003] The invention provides a silicon powder particle precipitation and separation method, which solves the technical problems of high cost, low efficiency and environmental pollution caused by the use of a filter press to remove silicon powder in the prior art.

[0004] In order to solve at least one of the above technical problems, the technical solution adopted by the present invention is:

[0005] A method for precipitation and separation of silicon powder particles comprises the following steps: preparing a coagulation inducing solution; mixing the prepared coagulation inducing solution with a cut cooling liquid for precipitation, so that the silicon powder flocculates and is separated from the cooling liquid stock solution; wherein the coagulation inducing solution is used to induce the silicon powder to flocculate.

[0006] Furthermore, the step of preparing the coagulation inducing solution includes: dissolving an organic acid into a solvent in proportion to prepare a first mixed solution; and dissolving a coagulant into the first mixed solution in proportion to prepare the coagulation inducing solution.

[0007] Furthermore, the organic acid is dissolved in the solvent in proportion to prepare the first mixed solution, specifically: 40-70% of the organic acid by weight is dissolved in the solvent and stirred evenly to prepare the first mixed solution.

[0008] Furthermore, the organic acid is citric acid; the organic acid and the solvent are mixed together in a stirrer at room temperature, and the stirring time is 2-5 minutes.

[0009] Furthermore, the coagulant is dissolved in the first mixed solution in proportion to prepare the coagulation inducing solution, specifically: 10-20% by weight of the coagulant is dissolved in the first mixed solution, and stirred evenly to prepare the coagulation inducing solution.

[0010] Further, the coagulant is poly(diallyldimethylammonium chloride); the coagulant is put into a stirrer containing the first mixed solution at room temperature and stirred for 2-5 minutes.

[0011] Further, mixing the prepared aggregation induction solution with the cut coolant for precipitation includes the steps of: taking the aggregation induction solution with a weight ratio of 0.7-1% and dissolving it into the untreated coolant; stirring the aggregation induction solution and the coolant to mix; allowing the stirred aggregation induction solution and coolant to stand for a period of time for sedimentation; the silicon powder flocculates and sediments to the lower layer, and the upper layer is the clear liquid of the coolant.

[0012] Further, the mixing of the aggregation induction solution and the coolant is carried out by mechanical stirring for 1-2 minutes.

[0013] Further, the standing time after stirring is 10-30 minutes.

[0014] Further, the solvent is deionized water.

[0015] A method for precipitating and separating silicon powder particles designed by the present invention induces flocculation of micron-sized silicon powder particles in the coolant stock solution, can quickly precipitate the silicon powder, so that the silicon powder particles are separated from the coolant stock solution, is simple to operate, low in cost, easy to control, and has good separation effect. Detailed implementation mode

[0016] The following will cooperate with embodiments to detail the implementation mode of the present application, so as to fully understand and implement the process of how the present application uses technical means to solve technical problems and achieve technical effects.

[0017] This embodiment proposes a method for precipitating and separating silicon powder particles, and the steps include: preparing an aggregation induction solution; mixing the prepared aggregation induction solution with the cut coolant for precipitation to separate the silicon powder floc from the coolant stock solution.

[0018] Specifically, the steps of preparing the aggregation induction solution include:

[0019] Dissolve the organic acid into the solvent in proportion to make the first mixed solution.

[0020] Use a measuring cup to measure 100 ml of the solution, weigh the organic acid with a weight ratio of 40-70% with an electronic balance, pour the organic acid into the solution, and mix the organic acid and the solution in a stirrer at room temperature and stir for 2-5 minutes. After being stirred evenly by a stirring rod, the prepared mixed solution is the first mixed solution.

[0021] There are many types of organic acids, and citric acid is the best.

[0022] Next, dissolve the coagulant into the first mixed solution in proportion to prepare a coagulation-induced solution.

[0023] Weigh the coagulant with an electronic balance at a weight ratio of 10-20%, and dissolve the weighed coagulant into a stirrer containing the first mixed solution. Stir the above mixed solution at room temperature for 2-5 minutes. After being stirred evenly by a stirrer rod, the prepared mixed solution is the coagulation-induced solution.

[0024] The coagulant with the best effect is poly(diallyldimethylammonium chloride).

[0025] Furthermore, the solvent is deionized water.

[0026] Mix the prepared coagulation-induced solution with the cut coolant and precipitate. The steps include:

[0027] Weigh the coagulation-induced solution with an electronic balance, and calculate and take the coagulation-induced solution at a weight ratio of 0.7-1%, and dissolve it into the untreated coolant. Put the coagulation-induced solution and the coolant into a glass stirrer at room temperature and carry out mechanical stirring for 1-2 minutes.

[0028] Then let the stirred and mixed coagulation-induced solution and coolant stand for a period of time. Preferably, the standing time is 10-30 minutes. After standing, a layered interface can be seen from the outside of the transparent container. The upper layer above the interface is the clear liquid layer, and the clear liquid can be used as coolant for recycling; the lower layer is the precipitated layer of flocculated silicon powder particles, and the silicon powder particles below are all flocculated and deposited on the lower layer. To help those skilled in the art further understand the method of the present invention, the technical solutions of the present invention will be explained in detail below with specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0029] Collect 1T of dirty coolant for silicon wafer cutting (silicon powder content is 3%-5%), measure 100 ml of ionized water with a measuring cup, weigh citric acid at a weight ratio of 50% with an electronic balance, pour the citric acid into the ionized water, and mix the citric acid and the solution into a stirrer at room temperature and stir for 3 minutes to prepare the first mixed solution.

[0030] Weigh poly(diallyldimethylammonium chloride) at a weight ratio of 20% with an electronic balance, and dissolve the weighed poly(diallyldimethylammonium chloride) into a stirrer containing the first mixed solution. Stir the above mixed solution at room temperature for 4 minutes to prepare the coagulation-induced solution.

[0031] First, pump 1000L of untreated coolant stock solution into a container with a stir bar. Then, use an electronic balance to weigh the coagulation-induced solution and calculate to take 7L of the coagulation-induced solution and dissolve it into the coolant. Place the coagulation-induced solution and the coolant in a glass stirrer at room temperature for mechanical stirring to allow the flocculation-induced aqueous solution to fully contact the silicon powder and form large particle polymers that precipitate, and stir for 2 minutes. Utilize the chain-like adsorption bridging effect of poly(diallyldimethylammonium chloride), adjust the pH of the liquid with citric acid, play the role of reducing the ZETA potential on the surface of the silicon powder particles, and induce the flocculation and precipitation of the silicon micropowder particles.

[0032] Next, let the stirred and mixed coagulation-induced solution and coolant stand for a period of time. After standing for 20 minutes, after the standing is completed, a layered interface appears in the transparent container. The supernatant layer is above the interface, accounting for 60% of the total height of the liquid in the container, and the solid content therein is 0.01%. The lower layer is the precipitated layer of flocculated silicon powder particles.

[0033] Using a method for separating and precipitating silicon powder particles designed by the present invention, inducing flocculation of micron-sized silicon powder particles in the coolant stock solution can quickly precipitate the silicon powder, so that the silicon powder particles are separated from the coolant stock solution. The operation is simple, the cost is low, it is easy to control, and the separation effect is good.

[0034] The above has introduced in detail a printing glass paste process provided by an embodiment of the present application. The description of the above embodiments is only used to help understand the structure and core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present application.

[0035] As certain terms are used in the specification and claims to refer to specific components. Those skilled in the art should understand that different manufacturers may use different terms to refer to the same component. The specification and claims do not use the difference in name as a way to distinguish components, but use the difference in function of the components as the criterion for distinction. The term "comprising" mentioned throughout the specification and claims is an open-ended term, so it should be interpreted as "including but not limited to". "Substantially" means within an acceptable error range. Those skilled in the art can solve the technical problem within a certain error range and basically achieve the technical effect. The subsequent description in the specification is the preferred implementation manner for implementing the present application, but the description is still for the purpose of explaining the general principle of the present application and is not used to limit the scope of the present application. The protection scope of the present application shall be determined by what is defined by the appended claims.

[0036] It should also be noted that the term "comprising", "including" or any other variation thereof is intended to cover non-exclusive inclusion, so that a commodity or system comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or elements inherent to such commodity or system. Without further limitation, there are additional identical elements in the commodity or system.

[0037] The above description shows and describes several preferred embodiments of the present application. However, as mentioned above, it should be understood that the present application is not limited to the forms disclosed herein, should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be changed within the scope of the concept of the present application described herein through the above teachings or the technology or knowledge in the relevant field. And any changes and modifications made by those skilled in the art without departing from the spirit and scope of the present application shall fall within the protection scope of the appended claims of the present application.

Claims

1. A method for precipitating and separating silicon powder particles, characterized in that , The steps include: configuring a flocculation-induced solution; mixing and precipitating the configured flocculation-induced solution with the cut coolant so that the silicon powder flocculates and separates from the original coolant; wherein, the flocculation-induced solution is used to induce the flocculation of the silicon powder; Configuring the flocculation-induced solution: dissolving citric acid with a weight ratio of 40 - 70% in deionized water, and stirring to form a first mixed solution; then adding poly(diallyldimethylammonium chloride) with a weight ratio of 10 - 20%, and stirring to form the flocculation-induced solution; Adding the flocculation-induced solution to the cut coolant according to a weight ratio of 0.7 - 1% of the cut coolant and stirring; After standing, the silicon powder flocculates and deposits, and the supernatant is the recyclable coolant.

2. The method for precipitating and separating silicon powder particles according to claim 1, characterized in that, Mixing the citric acid and the deionized water into a stirrer at room temperature and stirring for 2 - 5 min.

3. A method for precipitating and separating silicon powder particles according to claim 2, characterized in that, Putting the poly(diallyldimethylammonium chloride) into the stirrer containing the first mixed solution at room temperature and stirring for 2 - 5 min.

4. A method for precipitating and separating silicon powder particles according to any one of claims 1-3, characterized in that, The step of mixing and precipitating the configured flocculation-induced solution with the cut coolant includes: taking the flocculation-induced solution with a weight ratio of 0.7 - 1% and dissolving it into the untreated coolant; stirring the flocculation-induced solution and the coolant to mix; allowing the stirred flocculation-induced solution and coolant to stand for a period of time for deposition; the silicon powder flocculates and deposits to the lower layer, and the upper layer is the clear liquid of the coolant.

5. A method for precipitating and separating silicon powder particles according to claim 4, characterized in that The mixing of the flocculation-induced solution and the coolant is carried out by mechanical stirring for 1 - 2 min.

6. The method for precipitating and separating silicon powder particles according to claim 5, characterized in that, The standing time after stirring is 10 - 30 min.