阅读说明：本技术 一种研磨废浆料中的碳化硼回收利用的方法及其应用方法 (Method for recycling boron carbide in grinding waste slurry and application method thereof ) 是由 周志豪 王海呈 李贤途 李志宇 梁彬彬 于 2019-09-03 设计创作，主要内容包括：本发明公开了一种研磨废浆料中的碳化硼回收利用的方法,包括以下步骤：步骤1,研磨废浆料的收集：将蓝宝石研磨制程作业后的废浆料通过桶装的方式对其进行收集；步骤2,固液分离：将步骤1收集到的研磨废浆料,进行固液分离,沉淀后,提取底部的下层粉料备用；其中,固液分离采用的方式为重力沉淀法,沉淀时间为30～60min；步骤3,脱水烘干：提取步骤2的下层粉料至脱水机中进行脱水、烘干,获得含水率在5～10％的废弃旧干粉；其中脱水机的转速为600～2000rpm,脱水时间为10～20min,烘烤温度为80～120℃；步骤4,粒径筛分：将步骤3获得的废弃旧干粉放置到粒径分选机上进行分选,获得筛分后的碳化硼回收粉料。(The invention discloses a method for recycling boron carbide in grinding waste slurry, which comprises the following steps: step 1, collecting grinding waste slurry: collecting waste slurry after the sapphire grinding process operation in a barreling mode; step 2, solid-liquid separation: carrying out solid-liquid separation on the grinding waste slurry collected in the step 1, precipitating, and extracting powder on the lower layer at the bottom for later use; wherein the solid-liquid separation adopts a gravity precipitation method, and the precipitation time is 30-60 min; step 3, dewatering and drying: extracting the lower-layer powder obtained in the step 2, dehydrating and drying the lower-layer powder in a dehydrator to obtain waste dry powder with the water content of 5-10%; wherein the rotating speed of the dehydrator is 600-2000 rpm, the dehydrating time is 10-20 min, and the baking temperature is 80-120 ℃; step 4, particle size screening: and (4) placing the waste dry powder obtained in the step (3) on a particle size separator for separation to obtain the boron carbide recovered powder after screening.)

1. A method for recycling boron carbide in grinding waste slurry is characterized by comprising the following steps:

step 1, collecting grinding waste slurry:

collecting waste slurry after the sapphire grinding process operation in a barreling mode;

step 2, solid-liquid separation:

carrying out solid-liquid separation on the grinding waste slurry collected in the step 1, precipitating, and extracting powder on the lower layer at the bottom for later use; wherein the solid-liquid separation adopts a gravity precipitation method, and the precipitation time is 30-60 min;

step 3, dewatering and drying:

extracting the lower-layer powder obtained in the step 2, dehydrating and drying the lower-layer powder in a dehydrator to obtain waste dry powder with the water content of 5-10%; wherein the rotating speed of the dehydrator is 600-2000 rpm, the dehydrating time is 10-20 min, the baking temperature is 80-120 ℃, and the baking time is 120-150 min;

step 4, particle size screening:

and (4) placing the waste dry powder obtained in the step (3) on a particle size separator for separation to obtain the boron carbide recovered powder after screening.

2. The method according to claim 1, wherein the method comprises the steps of: the dispersing agent comprises a pH regulator and active ions.

3. The method according to claim 2, wherein the method comprises: the pH regulator is one or more of acetic acid, citric acid, oxalic acid, benzoic acid, sorbic acid, NaOH, KOH, NH4OH, ethylenediamine, ethylene glycol and triethanolamine.

4. The method according to claim 1, wherein the method comprises the steps of: the active ions are one or more of fluorine, chlorine, sulfate, nitrate, sulfite, iron and aluminum.

5. The boron carbide reclaimed powder obtained by the method for reclaiming and utilizing boron carbide in grinding waste slurry according to any one of claims 1 to 4.

6. The boron carbide reclaimed powder according to claim 5, wherein: the average grain size of the boron carbide recovered powder is 5-40 um.

7. The use of the boron carbide reclaimed powder of claim 6 in a copper polishing process.

8. The method for applying the boron carbide reclaimed powder according to claim 6, comprising the steps of:

A. uniformly mixing the boron carbide recovered powder with a dispersing agent to prepare copper polishing slurry; wherein the addition amount of the boron carbide recovery powder accounts for 3-10% of the weight of the copper polishing slurry, and the addition amount of the dispersant accounts for 1-5% of the weight of the copper polishing slurry;

B. adding the copper polishing slurry prepared in the step A into a copper polishing machine, and grinding a wafer placed on a ceramic disc through a metal grinding disc, wherein the rotating speed of the copper polishing machine is 20-50 rpm, and the pressure is 100-250 g/cm²The initial spraying amount of the slurry is 0.3-0.8 g/min/pcs, and the removal thickness is 25-45 um.

Technical Field

The invention relates to a method for recycling boron carbide in grinding waste slurry and an application method thereof.

Background

Sapphire material has a series of characteristics of high strength and hardness, high temperature resistance, abrasion resistance, strong corrosion resistance, excellent light transmission performance, excellent electrical insulation performance and the like, is applied to various complex environments due to stable optical and physicochemical characteristics, is widely applied to the fields of military infrared devices, missiles, submarines, satellite space technology, detection, high-power strong laser and the like, and is also applied to microelectronics, photoelectrons, semiconductors and information display.

The sapphire substrate processing includes rough grinding, finish grinding, copper polishing, and polishing (as shown in fig. 1), and a large amount of boron carbide abrasive is required in the grinding processing. According to statistics, the grinding waste liquid amount generated by grinding and processing the sapphire substrate in 2012 in China exceeds more than 3000 tons, wherein boron carbide abrasive is a main consumable in the sapphire processing process, but due to the lack of an effective processing technology, the waste liquid cannot be processed in time, and great pressure is caused to enterprise cost and environmental protection. Therefore, an urgent need is provided for recycling boron carbide in the grinding waste liquid generated by processing the sapphire substrate of the LED. If the boron carbide in the grinding waste liquid can be recovered, the high-efficiency cyclic utilization of the boron carbide can be realized, the usage amount of boron carbide grinding materials can be greatly reduced, and the cost is saved.

The existing sapphire substrate processing comprises the following specific steps:

step 1, a coarse grinding process, wherein boron carbide powder (No. 220 or No. 240) is matched with a suspension dispersant, so that the powder is not rapidly precipitated in a slurry barrel. Then inputting the sapphire substrate into a grinding machine for double-side grinding of the sapphire substrate, and processing the sapphire substrate under the parameters of stable rotating speed, pressure, slurry flow and the like. The fine grinding is generally divided into coarse grinding and fine grinding, which are mainly divided into coarse grinding to increase the removal rate, trimming the surface line shear mark, and fine grinding to make the roughness uniform. The method comprises the following specific steps: and the fine grinding is used as single slurry, the used boron carbide powder is uniformly collected to remove most of water, and then the boron carbide powder is introduced into the coarse grinding process for use.

Step 2, copper polishing process, the existing technology mostly uses artificial synthetic diamond, and grinding is carried out on a grinding disc made of metal materials after being matched with a dispersing agent, so as to reduce a damaged layer and obtain more detailed surface quality.

And 3, a polishing process, namely introducing colloid solution such as alumina or silicon dioxide into a polishing machine for the most part, and then carrying out chemical mechanical polishing on the surface of the wafer. To achieve a finer surface roughness (Ra), a longer operation time is usually required to balance the chemical and mechanical forces and obtain better quality.

In view of the above, it can be known that the high pollutants generated in the processing process in the prior art, such as the grinding powder, the copper slurry, the polishing colloid solution, etc., generate suspended solids which also cause inconvenience in wastewater treatment, resulting in increased cost. Therefore, the method still has an optimized space in the actual mass production operation.

Disclosure of Invention

Aiming at the problems, the invention provides a method for recycling boron carbide in grinding waste slurry and an application method thereof.

In order to achieve the above object of the present invention, the present invention provides a method for recycling boron carbide in grinding waste slurry, comprising the steps of:

step 1, collecting grinding waste slurry:

collecting waste slurry after the sapphire grinding process operation in a barreling mode;

step 2, solid-liquid separation:

carrying out solid-liquid separation on the grinding waste slurry collected in the step 1, precipitating, and extracting powder on the lower layer at the bottom for later use; wherein the solid-liquid separation adopts a gravity precipitation method, and the precipitation time is 30-60 min;

step 3, dewatering and drying:

extracting the lower-layer powder obtained in the step 2, dehydrating and drying the lower-layer powder in a dehydrator to obtain waste dry powder with the water content of 5-10%; wherein the rotating speed of the dehydrator is 600-2000 rpm, the dehydrating time is 10-20 min, the baking temperature is 80-120 ℃, and the baking time is 120-150 min;

step 4, particle size screening:

and (4) placing the waste dry powder obtained in the step (3) on a particle size separator for separation to obtain the boron carbide recovered powder after screening.

Further, the dispersing agent comprises a pH regulator and active ions.

Further, the pH regulator is one or more of acetic acid, citric acid, oxalic acid, benzoic acid, sorbic acid, NaOH, KOH, NH4OH, ethylenediamine, ethylene glycol and triethanolamine.

Further, the active ions are one or more of fluorine, chlorine, sulfate, nitrate, sulfite, iron and aluminum.

The invention also provides boron carbide recovered powder prepared by the method for recycling boron carbide in the waste grinding slurry.

Further, the average grain size of the boron carbide recovered powder is 5-40 um.

The invention also provides application of the boron carbide recovered powder in a copper polishing processing technology.

The invention also provides an application method of the boron carbide recovered powder, which comprises the following steps:

A. uniformly mixing the boron carbide recovered powder with a dispersing agent to prepare copper polishing slurry; wherein the addition amount of the boron carbide recovery powder accounts for 3-10% of the weight of the copper polishing slurry, and the addition amount of the dispersant accounts for 1-5% of the weight of the copper polishing slurry;

B. adding the copper polishing slurry prepared in the step A into a copper polishing machine, and grinding a wafer placed on a ceramic disc through a metal grinding disc, wherein the rotating speed of the copper polishing machine is 20-50 rpm, and the pressure is 100-250 g/cm²The initial spraying amount of the slurry is 0.3-0.8 g/min/pcs, and the removal thickness is 25-45 um.

From the above description of the structure of the present invention, compared with the prior art, the present invention has the following advantages:

according to the method for recycling the boron carbide in the waste grinding slurry, provided by the invention, the boron carbide powder in the waste grinding slurry for sapphire is recycled, and through the processes of dehydration, drying and screening, the proper powder particle size is obtained and the powder particle size is matched with a dispersing agent to be used in the copper polishing process, so that the effect of recycling is achieved, the surface quality of the polished sapphire substrate is the same, the pollution is reduced, the treatment efficiency of waste water is improved, and the cost is saved.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention.

In the drawings:

FIG. 1 is a prior art process for processing a sapphire substrate;

FIG. 2 is a flowchart of the method for recycling boron carbide in the polishing waste slurry according to the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

According to the method for recycling the boron carbide in the waste grinding slurry, provided by the invention, the boron carbide powder in the waste grinding slurry for sapphire is recycled, and the proper powder particle size is obtained through the dehydration, drying and screening processes and is matched with the dispersing agent to be used in the copper polishing process, so that the effect of recycling is achieved, the surface quality of the polished sapphire substrate is the same, the pollution is reduced, the treatment efficiency of waste water is improved, and the cost is saved.

The invention provides a method for recycling boron carbide in grinding waste slurry, which is characterized by comprising the following steps of:

step 1, collecting grinding waste slurry:

collecting waste slurry after the sapphire grinding process operation in a barreling mode;

step 2, solid-liquid separation:

carrying out solid-liquid separation on the grinding waste slurry collected in the step 1, precipitating, and extracting powder on the lower layer at the bottom for later use; wherein the solid-liquid separation adopts a gravity precipitation method, and the precipitation time is 30-60 min; in this embodiment, since the boron carbide powder has a heavy weight, it will precipitate rapidly, and after precipitation, the upper layer of water can be directly drained to obtain the lower layer of powder.

Step 3, dewatering and drying:

extracting the lower-layer powder obtained in the step 2, dehydrating and drying the lower-layer powder in a dehydrator to obtain waste dry powder with the water content of 5-10%; wherein the rotating speed of the dehydrator is 600-2000 rpm, the dehydrating time is 10-20 min, the baking temperature is 80-120 ℃, and the baking time is 120-150 min; in this embodiment, the water content of the extracted lower powder in step 2 is 65-80%, so that the lower powder needs to be dehydrated and dried, and waste gas powder with the water content of 5-10% can be obtained.

Step 4, particle size screening:

placing the waste dry powder obtained in the step (3) on a particle size separator for separation to obtain the boron carbide recovered powder after screening; in this embodiment, in order to achieve a certain roughness of the copper polishing process, it is preferable to screen the boron carbide powder with a particle size of 5-40 um, and the boron carbide powder with a particle size in this range has a better removal rate and surface roughness on the metal polishing disk.

Further, the dispersing agent comprises a pH regulator and active ions.

Further, the pH regulator is one or more of acetic acid, citric acid, oxalic acid, benzoic acid, sorbic acid, NaOH, KOH, NH4OH, ethylenediamine, ethylene glycol and triethanolamine.

Further, the active ions are one or more of fluorine, chlorine, sulfate, nitrate, sulfite, iron and aluminum.

By adopting the mode, the removal rate of the material can be improved, and the surface roughness can be changed.

The invention also provides boron carbide recovered powder prepared by the method for recycling boron carbide in the grinding waste slurry.

Further, the average grain size of the boron carbide recovered powder is 5-40 um.

The invention also provides application of the boron carbide recovered powder in a copper polishing processing technology.

The invention also provides an application method of the boron carbide recovered powder, which comprises the following steps:

A. uniformly mixing the boron carbide recovered powder with a dispersing agent to prepare copper polishing slurry; wherein the addition amount of the boron carbide recovery powder accounts for 3-10% of the weight of the copper polishing slurry, and the addition amount of the dispersant accounts for 1-5% of the weight of the copper polishing slurry;

B. adding the copper polishing slurry prepared in the step A into a copper polishing machine, and grinding a wafer placed on a ceramic disc through a metal grinding disc, wherein the rotating speed of the copper polishing machine is 20-50 rpm, and the pressure is 100-250 g/cm²The initial spraying amount of the slurry is 0.3-0.8 g/min/pcs, and the removal thickness is 25-45 um.

By adopting the above mode, namely in the embodiment, the disk surface shape of the metal grinding disk adopts an Archimedes spiral type, and the depth of the groove of the disk surface is preferably 0.2-0.4 mm, and the width of the groove distance is preferably 1-3 mm. And the surface roughness after copper polishing is 0.2-0.5 um, all defects can be removed through subsequent polishing procedures, the flatness Warp can be less than 15um, bow < -7um, and the optical surface grade can be achieved.

The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.