Filter-pressing separation and recovery method and system for crystalline silicon wire cutting waste mortar

Abstract

The invention discloses a filter-press separation and recovery method and system for crystalline silicon wire cutting waste mortar. The filter-press separation and recovery method comprises the steps of waste mortar blending, temperature adjustment control, centrifugal separation and filter-press separation. The recycling system comprises a first blending tank, a first temperature adjusting tank, a first centrifugal machine, a filter press and a recycled clear liquid tank; the first blending tank is connected with a waste mortar feeding pipe and a cutting liquid feeding pipe, and the cutting liquid feeding pipe is connected with the clear liquid recycling tank and an external liquid supply part; the first blending tank is provided with a first blending supply path; the first temperature regulation tank is provided with a first temperature regulation supply path; the first centrifugal machine is provided with a first centrifugal supply path; the filter press is provided with a waste residue discharge path and a liquid discharge path. Through combination of density adjustment and heating, the sand production rate of large-particle sand during centrifugal separation is increased, and the sand uniformity is improved. Secondary treatment of compounding can be achieved, finished sand can be centrifuged, and the recycling rate is high. Operation is stable and reliable, implementation, popularization and application are easy, and high economic value is achieved.

Description

Technical Field

[0001] The invention relates to a method and system for pressure filtration separation and recovery of waste mortar from crystalline silicon wire cutting, and belongs to the technical field of recycling and utilization of waste mortar from crystalline silicon wire cutting. Background Art

[0002] Silicon wafer is an important term in the field of microelectronics technology, usually referring to a thin slice of high-purity crystalline silicon. It plays a key role in the semiconductor industry as a substrate for chips used to manufacture electronic circuits. Silicon wafers can be in the form of single crystal silicon or polycrystalline silicon, of which single crystal silicon has higher purity and uniformity and is often used in high-performance electronic devices, while polycrystalline silicon is widely used in solar cells due to its lower cost and higher efficiency.

[0003] Silicon wafers need to be wire-cut during the processing process, and the cutting fluid plays a very critical role in wire cutting. The cutting fluid will produce waste mortar during the cutting operation. This type of waste mortar is crystalline silicon wire cutting waste mortar, which is a mixture of cutting fluid, silicon carbide, iron powder, etc. The waste mortar needs to be recycled, mainly for the recovery and reuse of larger particle sand bodies, for compounding or product sand recovery.

[0004] In traditional processes, centrifuges are generally used to separate large solid particles, and then solid-liquid separation is performed through filter pressing to achieve waste residue and filtrate recovery. However, traditional crystalline silicon wire cutting waste slurry has a certain viscosity, and the solid particles are poorly distributed in it, resulting in a small centrifugal separation volume, a low recovery rate, and a high waste residue output rate at the back end, which greatly affects the economic value of recovery. Summary of the invention

[0005] The purpose of the present invention is to solve the deficiencies of the above-mentioned prior art, and to propose a method and system for filtering, separating and recovering waste slurry from crystalline silicon wire cutting in view of the low economic value of the traditional crystalline silicon wire cutting waste slurry.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is: A method for separating and recovering waste slurry from crystalline silicon wire cutting by filtration pressure comprises the following steps: S1 waste mortar preparation, adding cutting fluid into the waste mortar to prepare a mixed slurry with a density of 1.52g / cm³~1.53g / cm³; S2 temperature control, heating the prepared mixed slurry to 60℃±2℃ to obtain heated slurry; S3 centrifugal separation, centrifugal separation of the heated slurry to obtain recovered sand and centrifugal slurry; S4 is a filter press separation, in which the centrifugal slurry is filtered to obtain waste residue and recovered cutting fluid, and the recovered cutting fluid is used as the cutting fluid to participate in the waste mortar preparation in step S1.

[0007] Preferably, it includes: S5: Compounding of recycled abrasive materials: Compounding the recycled abrasive materials and the recycled cutting fluid into a compound mixed slurry with a density of 1.52g / cm³~1.53g / cm³; S6 secondary temperature control, heating the compound mixed slurry to 60°C±2°C to obtain a heated compound slurry; S7 secondary centrifugal separation, centrifugal separation of the heated composite slurry to obtain finished sand material and centrifugal composite slurry; S8 is a secondary filtration separation, which filters the centrifugal compound slurry to obtain secondary waste residue and secondary recovered cutting fluid.

[0008] The present invention also proposes a filter press separation and recovery system for waste slurry from crystalline silicon wire cutting, comprising a first preparation tank for preparing waste slurry, a first temperature control tank for temperature control, a first centrifuge for centrifugal separation, a filter press for filter press separation, and a recovery clear liquid tank for storing the recovered cutting liquid; The first mixing tank is connected with a waste mortar feeding pipe and a cutting liquid feeding pipe, and the cutting liquid feeding pipe is connected with the recovery clear liquid tank and the external liquid supply part respectively; The first preparation tank is provided with a first preparation supply path connected to the first temperature regulating tank; The first temperature regulating tank is provided with a first temperature regulating supply path for feeding material toward the first centrifuge; The first centrifuge is provided with a first centrifugal supply path for feeding material toward the filter press; The filter press is provided with a waste residue discharge path for discharging waste residues and a liquid discharge path connected to the clean liquid recovery tank.

[0009] Preferably, it comprises a second mixing tank for compounding the recovered sand material, a second temperature control tank for secondary temperature control, and a second centrifuge for secondary centrifugal separation; The recovery clear liquid tank is provided with a recovery clear liquid supply path connected to the second blending tank; The second preparation tank is provided with a second preparation supply path connected to the second temperature regulating tank; The second temperature regulating tank is provided with a second temperature regulating supply path for feeding material toward the second centrifuge; The second centrifuge is provided with a second centrifugal supply path for supplying material toward the filter press.

[0010] The beneficial effects of the present invention are mainly reflected in: 1. By combining density adjustment with heating, the sand output rate of large particles during centrifugal separation is improved, and the uniformity of the sand is also improved.

[0011] 2. It can realize secondary processing of compounding and centrifuge finished sand materials with high recycling rate.

[0012] 3. Stable and reliable operation, easy to implement and promote application, and has high economic value. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings: Figure 1 It is a schematic flow chart of the filter pressing separation and recovery method of crystalline silicon wire cutting waste mortar according to the present invention.

[0014] Figure 2 It is a schematic flow chart of a preferred embodiment of the method for pressure filtration separation and recovery of crystalline silicon wire sawing waste mortar of the present invention.

[0015] Figure 3 It is a structural schematic diagram of the filter pressure separation and recovery system of the crystalline silicon wire cutting waste slurry of the present invention. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] The present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant inventions, rather than to limit the inventions. It should also be noted that, for ease of description, only the parts related to the relevant inventions are shown in the accompanying drawings. It should be noted that, in the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0018] The present invention provides a method for separating and recovering waste slurry from crystalline silicon wire cutting by filtration pressure, such as Figure 1 As shown, the following steps are included: Preparation of waste mortar: Add cutting fluid into the waste mortar to prepare a mixed slurry with a density of 1.52g / cm³~1.53g / cm³.

[0019] The temperature is controlled to raise the temperature of the prepared mixed slurry to 60°C ± 2°C to obtain a heated slurry.

[0020] Centrifugal separation is performed on the heated slurry to obtain recovered sand and centrifugal slurry.

[0021] Filter pressing separation, filter pressing the centrifugal slurry to obtain waste residue and recovered cutting fluid, and the recovered cutting fluid is used as the cutting fluid to participate in the preparation of waste mortar.

[0022] Specific implementation process and principle description: When the crystalline silicon wire cutting is in operation, the wire cutting slurry is in a circulating operation mode, and the crystalline silicon wire cutting waste slurry includes viscous waste with higher viscosity and circulating slurry participating in the circulation. The viscous waste is the discharge, and the circulating slurry is the circulating slurry that cannot reach the recycling parameters.

[0023] In view of this situation, this case uses waste mortar as the basis, and mixes waste mortar and cutting fluid into a mixed slurry with a density of 1.52g / cm³~1.53g / cm³. The mixed slurry in this density range has moderate viscosity and is easy to disperse solid particles. This density range is also an indicator feature of the circulating slurry. The circulating slurry in this density range meets the process requirements of wire cutting, that is, meets the distribution requirements of its solid particles.

[0024] The prepared mixed slurry is heated, and the solid particles of the heated slurry are distributed more evenly. Centrifugal separation is performed in a uniformly distributed state, and the particle size of the recovered sand is large and uniform. The recovered sand meets the needs of secondary compound wire cutting slurry and can be recycled.

[0025] Finally, waste residue and recovered cutting fluid are obtained by filter pressing and separation. The recovered cutting fluid can be used for compounding of circulating slurry or as cutting fluid for waste mortar.

[0026] In a specific embodiment, Figure 2 As shown, the filter pressing separation and recovery method of the waste slurry from the crystalline silicon wire cutting also includes secondary recovery, including the following steps: Compounding of recycled abrasive materials: compounding recycled abrasive materials and recycled cutting fluid into a compound mixed slurry with a density of 1.52g / cm³~1.53g / cm³; Secondary temperature control, heating the compound mixed slurry to 60°C±2°C to obtain a heated compound slurry; Secondary centrifugal separation, centrifugal separation of the heated composite slurry to obtain finished sand material and centrifugal composite slurry; Secondary filtration separation: the centrifugal compound slurry is filtered to obtain secondary waste residue and secondary recovered cutting fluid.

[0027] Specifically, since the waste slurry from crystalline silicon wire cutting contains cutting fluid, silicon carbide, iron powder, alcohols, surfactants and other ingredients, it contains certain flocculent and other impurities. After the first density adjustment and heating, the recovered sand separated has a greatly improved particle size uniformity compared to the traditional separation process, but the recovered sand is still difficult to meet the particle size uniformity requirements of the finished sand, and some smaller particles still remain.

[0028] In view of this situation, a secondary recovery process was adopted, that is, the sampled recovered sand material was compounded with the recovered cutting fluid, and then secondary temperature control and secondary centrifugal separation were performed to obtain finished sand with guaranteed particle size uniformity, which met the demand for finished sand recovery. This finished sand met the market circulation demand. The recovered cutting fluid from the first recovery was used in the compounding. After the filter press, the recovered cutting fluid can effectively remove impurities. After compounding, the centrifugal interference was reduced, so that the quality of the finished sand of the secondary centrifugal separation was guaranteed. Finally, the secondary waste residue and the secondary recovered cutting fluid were recovered separately through secondary filter press separation. The secondary recovered cutting fluid continues to participate in the circulation.

[0029] The filter press separation and recovery system of the crystalline silicon wire cutting waste slurry of the present invention is described in detail. Figure 3 As shown, it includes a first mixing tank for mixing waste mortar, a first temperature control tank for temperature control, a first centrifuge for centrifugal separation, a filter press for filter pressure separation, and a recovery clear liquid tank for storing recovered cutting fluid.

[0030] The first mixing tank is connected with a waste mortar feeding pipe and a cutting liquid feeding pipe, and the cutting liquid feeding pipe is respectively connected with the recovered clear liquid tank and the external liquid supply part.

[0031] The first preparation tank includes a first preparation supply path connected to the first temperature control tank.

[0032] The first temperature adjustment tank is provided with a first temperature adjustment supply path for supplying material toward the first centrifuge.

[0033] The first centrifuge is provided with a first centrifugal supply path for supplying material toward the filter press.

[0034] The filter press is provided with a waste residue discharge path for discharging waste residues and a liquid discharge path connected to a clear liquid recovery tank.

[0035] Specific implementation process and principle description: First, the waste mortar enters the first mixing tank through the waste mortar feeding pipe, and the cutting liquid is fed into the first mixing tank through the cutting liquid feeding pipe, and the cutting liquid feeding pipe is supplied through the recovery clear liquid tank and / or the external liquid supply part. The density of the mixed slurry is adjusted in the first mixing tank.

[0036] The mixed slurry after density adjustment enters the first temperature control tank along the first mixing supply path, is heated in the first temperature control tank, and is fed to the first centrifuge through the first temperature control supply path. The feed is separated into recovered sand and centrifugal slurry by the first centrifuge.

[0037] At this time, the recovered sand material can be recycled and reused in the configuration of the circulating slurry. The centrifugal slurry is fed to the filter press from the first centrifugal supply path to separate the waste residue and the recovered cutting fluid, and the recovered cutting fluid enters the recovery clear liquid tank along the drainage path.

[0038] It should be noted that when the first mixing tank is mixing, the cutting liquid supply to the cutting liquid feeding pipe can be achieved through the recovery clear liquid tank.

[0039] In a preferred embodiment, if Figure 3 As shown, it is equipped with a second mixing tank for compounding of recovered sand materials, a second temperature control tank for secondary temperature control, and a second centrifuge for secondary centrifugal separation.

[0040] The recovery clear liquid tank is provided with a recovery clear liquid supply path connected to the second mixing tank.

[0041] The second preparation tank includes a second preparation supply path connected to the second temperature control tank.

[0042] The second temperature adjustment tank is provided with a second temperature adjustment supply path for supplying material toward the second centrifuge.

[0043] The second centrifuge is provided with a second centrifugal supply path for supplying material toward the filter press.

[0044] Specifically, the recovered sand and the recovered cutting fluid are compounded in the second mixing tank, and after density adjustment, they enter the second temperature control tank for temperature control. After adjustment, they are supplied to the second centrifuge through the second mixing supply path to separate the finished sand and the centrifugal compound slurry. At this time, the finished sand meets the market circulation quality requirements.

[0045] The centrifugal compound slurry is fed to the filter press from the second centrifugal supply path to separate the secondary waste residue and the secondary recovered cutting liquid, and the secondary recovered cutting liquid enters the recovery clear liquid tank along the discharge path.

[0046] From the above description, it can be found that by combining density adjustment with heating, the sand discharge rate of large-particle sand during centrifugal separation is improved, and the uniformity of sand is also improved. It can achieve secondary processing of compounding, and can centrifuge finished sand with a high recycling rate. It is stable and reliable in operation, easy to implement and promote, and has high economic value.

[0047] The term "comprise" or any other similar term is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus / device that includes a list of elements includes not only those elements but also other elements not expressly listed, or also includes elements inherent to such process, method, article, or apparatus / device.

[0048] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A method for separating and recovering waste slurry from crystalline silicon wire cutting by filtration pressure, characterized in that The steps include: S1 waste mortar preparation, adding cutting fluid into waste mortar to prepare a mixed slurry with a density of 1.52g / cm³~1.53g / cm³; S2 temperature control, heating the prepared mixed slurry to 60℃±2℃ to obtain heated slurry; S3 centrifugal separation, centrifugal separation of the heated slurry to obtain recovered sand and centrifugal slurry; S4 is a filter press separation, in which the centrifugal slurry is filtered to obtain waste residue and recovered cutting fluid, and the recovered cutting fluid is used as the cutting fluid to participate in the waste mortar preparation in step S1.

2. The method for separating and recovering waste slurry from crystalline silicon wire cutting according to claim 1, characterized in that include: S5: Compounding of recycled abrasive materials: Compounding the recycled abrasive materials and the recycled cutting fluid into a compound mixed slurry with a density of 1.52g / cm³~1.53g / cm³; S6 secondary temperature control, heating the compound mixed slurry to 60°C±2°C to obtain a heated compound slurry; S7 secondary centrifugal separation, centrifugal separation of the heated composite slurry to obtain finished sand material and centrifugal composite slurry; S8 is a secondary filtration separation, which filters the centrifugal compound slurry to obtain secondary waste residue and secondary recovered cutting fluid.

3. A filter press separation and recovery system for waste slurry from crystalline silicon wire cutting, used for the operation of the filter press separation and recovery method for waste slurry from crystalline silicon wire cutting according to claims 1 and 2, characterized in that: It includes a first mixing tank for mixing waste mortar, a first temperature regulating tank for temperature control, a first centrifuge for centrifugal separation, a filter press for filter pressure separation, and a recovery clear liquid tank for storing the recovered cutting fluid; The first mixing tank is connected with a waste mortar feeding pipe and a cutting liquid feeding pipe, and the cutting liquid feeding pipe is connected with the recovery clear liquid tank and the external liquid supply part respectively; The first preparation tank is provided with a first preparation supply path connected to the first temperature regulating tank; The first temperature regulating tank is provided with a first temperature regulating supply path for feeding material toward the first centrifuge; The first centrifuge is provided with a first centrifugal supply path for feeding material toward the filter press; The filter press is provided with a waste residue discharge path for discharging waste residues and a liquid discharge path connected to the clean liquid recovery tank.

4. According to the filtration separation and recovery system for crystalline silicon wire sawing waste slurry according to claim 2, The method for separating and recovering waste slurry from crystalline silicon wire cutting by filtration pressure comprises: S5: Compounding of recycled abrasive materials: Compounding the recycled abrasive materials and the recycled cutting fluid into a compound mixed slurry with a density of 1.52g / cm³~1.53g / cm³; S6 secondary temperature control, heating the compound mixed slurry to 60°C±2°C to obtain a heated compound slurry; S7 secondary centrifugal separation, centrifugal separation of the heated composite slurry to obtain finished sand material and centrifugal composite slurry; S8 secondary filtration separation, filtering the centrifugal compound slurry to obtain secondary waste residue and secondary recovered cutting fluid; Features: It includes a second mixing tank for compounding the recovered sand material, a second temperature regulating tank for secondary temperature control, and a second centrifuge for secondary centrifugal separation; The recovery clear liquid tank is provided with a recovery clear liquid supply path connected to the second blending tank; The second preparation tank is provided with a second preparation supply path connected to the second temperature regulating tank; The second temperature regulating tank is provided with a second temperature regulating supply path for feeding material toward the second centrifuge; The second centrifuge is provided with a second centrifugal supply path for supplying material toward the filter press.

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