KR101362732B1 - Grinding agent for cement manufacturing minerals using diluted silicon sludge and grinding method using the same - Google Patents

Abstract

Disclosed is a waste silicon sludge recycling technology. The present invention provides a grinding agent for grinding minerals for manufacture of cement, wherein the grinding agent is classified from waste silicon sludge, comprises cutting oil included in the waste silicon sludge in a dilution concentration of 1/5 to 1/50. According to the present invention, provided is a method for improving grinding efficiency and quality of water curable products by applying the properties of components of the waste silicon sludge to the grinding process for water curable minerals without separate heat treatment, distillation, or a precise classifying process. [Reference numerals] (AA) Solid residue(liquid included); (BB) Waste sludge; (CC) Mixing tank; (DD) Wet separation(hydrocyclone, centrifuge, etc.); (EE) Liquid residue(liquid included); (FF) Solvent input tank; (GG) Utilize a grinding agent

Description

Grinding aid for mineral grinding for cement manufacturing using dilute silicon sludge and grinding method using the same {Grinding Agent For Cement Manufacturing Minerals Using Diluted Silicon Sludge And Grinding Method Using The Same}

The present invention relates to a method of using silicon sludge, a by-product generated during silicon wafer cutting, as a grinding aid, and more particularly, to efficiently separate solid and liquid components by adding a solvent to the sludge, and then separating liquid residues. It relates to a method of pulverizing the mineral for cement production using water (including some fine solid component).

Silicon, which is widely used as a wafer in the solar cell and semiconductor industries, is manufactured through a process of cutting a silicon ingot using a wire saw. In the cutting process, polishing slurries containing silicon carbide having an average particle diameter of about 10 microns are used, resulting in polishing sludge containing silicon carbide and other oxides as the main component of silicon carbide. Recently, a diamond saw is used to minimize the silicon carbide content used as an abrasive and to increase the production speed. In the manufacturing process of such a silicon wafer, polishing sludge containing silicon is generated.

In the past, silicon sludge has been landfilled by waste disposal companies, but in recent years, attempts have been made to recover materials such as cutting oil, silicon or silicon carbide contained in silicon sludge.

However, in the recycling method of the silicon sludge, most of them are concentrated on the development of the technology for separating the solid components and the liquid components used as cutting oil or recycling the separated solid components contained in the silicon sludge. The remaining liquid components are not utilized.

Representative techniques for recycling conventional silicon sludge include polishing slurry regeneration techniques, solids separation recovery techniques, and silicon carbide synthesis techniques.

For example, Korean Patent Laid-Open Publication No. 2003-84528 discloses a 1-20% weight ratio of non-ionic surfactant and 5-50% alcohol or solvent in a waste slurry for a predetermined time (more than 5 minutes to 10 hours). After the separation, the same minerals are formed in layers by centrifugal separators, and the layers are separated.Then, the oils are separated and put into separate containers using an oil pump for each layer, and then dried using a dryer (by product use) as needed. After this, it introduces the technology to separate and recycle by size by passing the classifier as needed.

In addition, Korean Patent No. 10-1188313 adds an agglomeration reaction step in the middle of the step centrifugal separation step in the regeneration of the solar cell wafer processing waste slurry to effectively separate metal impurities and fine particles in the cutting oil to increase the regeneration efficiency. Although the generation can be minimized, there are disadvantages in that a large amount of cost is generated through the distillation process to remove water, water is generated in the distillation process, and waste sludge is inevitably generated in the secondary centrifuge.

In Korean Patent No. 626,252, solid sludge is efficiently removed by separating waste sludge into solid and liquid components and introducing water-soluble components and solvents for removing organic matter into waste sludge to recover abrasives. By leaving it unattended, the process time is long and there is a problem of increasing the process equipment and the cost by repeating the cleaning process.

In addition, the Korean Patent Registration No. 10-1111649 provides a method for regenerating the abrasive from the waste sludge containing the abrasive used when cutting the silicon ingot with a metallic wise saw (liquid saw) There is no suggestion on how to use.

On the other hand, Korea Patent Registration 10-1194188 is a waste sludge (sludge) is recovered in high purity by vaporizing the cutting oil using a microwave in a dryer installed with a magnetron that generates microwaves, and the dried solids are separated and purified by component for industrial use It proposes a method of recycling from materials, but it is expensive to manufacture and operate microwave facilities and wind classification facilities, and there is a problem in maintaining the facilities.

Korean Laid-Open Patent No. 2003-84528 Korean Patent Registration No. 10-1188313 Korea Patent Registration No. 10-626252 Korea Patent Registration No. 10-1111649 Korean Patent Registration No. 10-1194188

In order to solve the above problems of the prior art, an object of the present invention is to provide a technique for recycling waste silicon sludge without elaborate refining process or high temperature heat treatment process.

In addition, an object of the present invention is to provide a grinding aid for pulverizing the mineral residue for the cement production of the liquid residue generated in the wet separation process.

In addition, an object of the present invention is to provide a fine grinding method of cement raw material and clinker using the above-mentioned grinding aid.

In order to achieve the above technical problem, the present invention is classified from waste silicon sludge, and composed of cutting oil contained in the waste silicon sludge, the dilution concentration of the cutting oil is for producing cement, characterized in that 1/5 ~ 1/50 It provides a grinding aid for mineral grinding.

In the present invention, the mineral for producing cement may include any mineral that is combined with minerals, cement clinker, or pulverized clinker used as a plastic raw material for cement clinker and added for cement production.

In the present invention, the grinding aid comprises a solid component, the solid component preferably comprises a silicon powder having an average particle diameter of less than 1 micron. In the present invention, the silicon powder may include surface oxidized silicon.

In addition, in the present invention, the solid component of the grinding aid shows a bimodal distribution, and the grinding aid may further include silicon carbide powder having an average particle diameter of 1 micron or more.

In the present invention, the cutting oil is preferably composed of at least one selected from the group consisting of polyethylene glycol, diethylene glycol and dimethylene glycol.

In addition, in the present invention, the cutting oil is preferably diluted with water in a solvent.

In the present invention, the mineral for producing cement may be a raw material mineral for cement clinker firing. In addition, the mineral for producing cement may be a cement clinker. In addition, the cement manufacturing mineral may be a cement additive.

In order to achieve the above another technical problem, the present invention provides a mineral grinding method, characterized in that the above-mentioned grinding aid is added to the grinding mill together with the mineral for cement production.

In the present invention, the grinding aid may be added to the grinding mill together with the mineral for producing cement.

In the present invention, when the mineral for producing cement is a cement clinker, the grinding aid is preferably blended in an amount of 0.2 to 0.5 wt% based on the total weight including the cement clinker. Also, at this time, a coagulation delay agent may be additionally added for grinding.

According to the present invention, in the silicon wafer polishing process, the cutting oil is composed of glycols (diethylene glycol, polyethylene glycol, etc.) to improve the grinding characteristics of the mineral, and a considerable portion of the fine solid component remaining after separation cannot be removed. Noting that it exists as a silicon oxide component that expresses its characteristics, it is applied to the grinding process of hydraulic minerals without separate heat treatment, distillation and precise classification process to provide a method of improving the grinding efficiency and quality of the produced hydraulic products. You can do it.

1 is a view schematically showing a separation and purification method of waste silicon sludge according to a preferred embodiment of the present invention.
Figure 2 is a particle size analysis of the solid phase components contained in the liquid residue generated after separation into hydrocyclones according to a preferred embodiment of the present invention.
Figure 3 is a SEM analysis of the solid phase components contained in the liquid residue generated after separation into hydrocyclones.

Hereinafter, the present invention will be described in detail through preferred embodiments of the present invention.

1 is a view schematically showing a method for separating and collecting a liquid residue from waste silicon sludge used as a grinding aid of the present invention.

Referring to Figure 1, waste silicon sludge is added to the mixing tank, the solvent is added to the mixing tank at an appropriate ratio. The mixed raw materials in the mixing bath are wet separated by a separation device such as hydrocyclone or centrifuge. The wet separation process separates the charged mixture into solid and liquid residues, depending on the specific gravity. In the present invention, the liquid residue is utilized as a grinding aid.

In the present invention, waste sludge or waste silicon sludge refers to a by-product generated during grinding or cutting of polysilicon or single crystal silicon ingot. In addition, in the present invention, 'liquid residue' refers to the liquid component remaining after separating the solid component of the coarse component in the wet separation process.

In the present invention, the grinding aid is prepared from a liquid component which is a by-product of the wet separation process. The liquid component contains cutting oil (diethylene glycol, polyethylene glycol, etc.) diluted with a solvent. It is preferable that the liquid component of the grinding aid of the present invention is diluted 5 to 50 times by weight of cutting oil contained in the silicon sludge. Dilution concentrations of less than 5 dilution ratios are unsuitable for hydrocyclone classification because of their high viscosity. In addition, the dilution ratio of 50 times or more is excessive in the amount of the solvent compared to the amount of the cutting oil, the effect of the grinding aid by the cutting oil component is lowered, and may be adversely affected by the hydration of the cement clinker when used as a subsequent grinding aid.

In addition, the liquid component in the present invention may include a solid component of the fine powder that is not separated in the wet separation process.

Table 1 is an analysis table analyzing the solid components of the fine particles contained in the liquid residue generated in the wet separation process of the present invention.

SiO ₂ (% by weight) Si (% by weight) SiC (% by weight) Fe + Fe ₂ O ₃ (wt%) Others (% by weight) 27.4 45.2 15.7 12.2 <0.5

As can be seen from the above table, the fine solid component of the fine particles contains a significant amount of SiO _{2 because the} fine silicon component is oxidized during the polishing of the silicon ingot.

Figure 2 illustrates the results of the particle size analysis of the particulate solid component contained in the liquid residue of the present invention. As can be seen from the particle size analysis results, the solid content represents a bimodal distribution in which coarse particles and coarse particles of 1 μm or less coexist.

In the present invention, the fine particles are composed of silicon powder. The silicon powder may include surface oxidized silicon oxide.

In the present invention, the fine particles preferably have an average particle diameter of 1 micron or less. In addition, the coarse particles are preferably present in the range of the average particle diameter of 5 microns or less. The coarse particles may be silicon carbide, and the coarse particles of 5 μm or more may cause wear of the grinder, and therefore, the coarse particles may be 10 wt% or less.

Figure 3 is a scanning electron micrograph of the particulate solid component contained in the liquid residue of the present invention. As shown, it can be confirmed that fine particles of 1 μm or less and coarse particles of 3 μm or more coexist.

The grinding aid of the present invention may employ a configuration containing less of the coarse particles, but in this case, an increase in time and cost required for wet classification of the silicon sludge occurs.

<Examples>

Silicon sludge having a cutting oil content of about 40% by weight, including polyethylene glycol, diethylene glycol, dimethylene glycol, and the like, was wet separated. About 5 to 50 times dilution with water based on the weight of the cutting oil contained in the silicon sludge, hydrocyclone classification was applied to obtain a liquid residue from the diluted silicon sludge.

In hydrocyclone classification, when the diluted silicon sludge tangentially flows into the cylindrical cyclone, the introduced silicon sludge is swiveled in the cylindrical cyclone, which causes centrifugal force to act on the diluted silicon sludge. As a result, the coarse particles are directed to the outer wall of the cyclone, which underflows and the liquid residue containing the fine particles overflows, thereby classifying the liquid residue.

Then, the grinding characteristics of the cement clinker and the mortar characteristics of the ground cement were measured while varying the addition amount of the recovered liquid residue. At this time, the cement clinker used for the crushing characteristics was used as a clinker having a size of 0.5 cm or less through the coarse grinding process. In order to evaluate the quality characteristics of the pulverized cement, 5% of gypsum was added to the cement clinker as a coagulation retardant and ground using a ball mill. Grinding characteristics of cement clinker were measured by air permeability test method (KS L 5106) of Portland cement, and the grinding characteristics were evaluated by measuring the required time of 3,500 ± 50 cm2 / g. In order to measure the quality of cement, mortar specimens were prepared according to KS L 5105 standard using crushed cement and subjected to standard curing, and then the compressive strength of each elapsed day was measured.

division Addition of water to cutting oil (% by weight) Liquid residue added in the grinding process (wt%) Cement Clinker Grinding Properties
(3,500 ± 50㎠ / g required time: min) Cement mortar compressive strength ratio (%) 1 day 3 days 7 days 28th No.1 - 0% 58 100 100 100 100 No.2 500 0.2 38 100 99 99 102 No.3 1.0 31 102 98 101 100 No.4 2.0 28 101 104 101 107 No.5 5.0 27 104 105 102 102 No.6 1250 0.2 40 101 101 103 104 No.7 1.0 34 105 99 102 100 No.8 2.0 30 105 100 100 103 No.9 5.0 29 105 105 106 109 No.10 2500 0.2 42 101 105 104 102 No.11 1.0 39 102 104 104 100 No.12 2.0 34 101 100 99 97 No.13 5.0 31 100 101 99 104 No.14 5000 0.2 48 102 100 98 100 No.15 1.0 44 100 100 101 99 No.16 2.0 42 100 100 102 104 No.17 5.0 41 99 93 94 96

Referring to the table above, it can be seen that the time required for the specific surface area to be 3,500 ± 50 ㎠ / g is dramatically shortened when the liquid residue is added as compared to the case where no liquid residue is added as the grinding aid. This is because DEG is present in the liquid residues generated at to express the grinding aid properties. Although the specific surface area is similar to 3,500 ± 50 cm2 / g, the mortar compressive strength of cement produced by using liquid residue as a grinding aid is relatively higher than that of cement without liquid residue (No.1). This is because the solid component of the fine powder contained in the liquid residue contains a SiO 2 component having a latent hydraulic property. In the case of No. 17, the cement mortar compressive strength is drastically reduced because part of the cement is hydrated in advance because of the large amount of dilution and addition of water in the wet separation process.

Claims (12)

Consists of liquid residues generated during the grinding or cutting of polysilicon or single crystal silicon ingots,
The liquid residue comprises a cutting oil and a solid component,
The cutting oil includes at least one selected from the group consisting of polyethylene glycol, diethylene glycol, and dimethylene glycol,
Said solid component comprises a silicon oxide grinding aid for grinding cement clinker, characterized in that. The method of claim 1,
And said solid phase component comprises a surface oxidized silicon powder having an average particle diameter of less than 1 micron. delete The method of claim 1,
The solid component of the grinding aid exhibits a bimodal distribution,
The grinding aid is a grinding aid for cement clinker grinding, characterized in that the average particle diameter further comprises silicon carbide powder of 1 micron or more. delete The method of claim 1,
The cutting oil is a grinding aid for cement clinker grinding, characterized in that the water is diluted with a solvent. delete delete delete The grinding | pulverization method of the cement clinker characterized by inject | pouring the grinding | pulverization adjuvant in any one of Claims 1, 2, 4, and 6 together with a cement clinker. 11. The method of claim 10,
The grinding aid is a grinding method of the cement clinker, characterized in that blended 0.2 to 0.5% by weight relative to the total weight including the cement clinker. 11. The method of claim 10,
Grinding method of cement clinker, characterized in that the addition of a coagulation delay agent.

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