Method for separating polishing material and regenerated polishing material

Patent metadata

Field	Value
Publication number	US-10017675-B2
Application number	US-201214367154-A
Country	US
Kind code	B2
Filing date	Dec 17, 2012
Priority date	Dec 27, 2011
Publication date	Jul 10, 2018
Grant date	Jul 10, 2018

Abstract

Method for separating a polishing material, which is capable of separating and recovering cerium oxide from a used polishing material that is mainly composed of cerium oxide and a regenerated polishing material which can be obtained by the separation method. This method for separating a polishing material is characterized in that a divalent alkaline earth metal salt is added into the slurry of the used polishing material, while controlling the temperature of the slurry within the range of 10-70 DEG C., thereby causing the polishing material to aggregate under such conditions that the mother liquor has a pH of less than 10.0 as the pH is converted to one at 25 DEG C. so that the polishing material is separated from the mother liquor.

First claim

The invention claimed is:

1. A method for separating a cerium oxide containing-abrasive from a used abrasive-containing slurry that contains the cerium oxide containing abrasive and a component derived from a polished object that has been polished in an abrasive device, the method comprising:
collecting the used abrasive-containing slurry discharged from the abrasive device;
adding a divalent alkali earth metal salt to the collected-used abrasive-containing slurry to form a mother liquid while a temperature of the collected-used abrasive-containing slurry is regulated in a range from 10 to 70° C.;
aggregating the abrasive when the mother liquid has a property of measured or converted pH of lower than 10 at 25° C. so that sedimentation of the abrasive occurs, the aggregated abrasive settles, and a supernatant solution containing the component derived from the polished object is formed; and
isolating the abrasive from the mother liquid;
wherein the cerium oxide containing-abrasive is mainly comprised of cerium oxide rare earth material, optionally also containing one or more additional rare earth elements, and the polished object is a glass.

2. The method of claim 1 , wherein the divalent alkali earth metal salt is a magnesium salt.

3. The method of claim 1 , wherein the range of the regulated temperature of the used abrasive-containing slurry during the adding step is from 10 to 40° C.

4. The method of claim 1 , wherein the collecting step comprises collecting the used abrasive slurry discharged from the abrasive device in a separation container, which comprises a temperature regulator, and the adding step comprises adding the divalent alkali earth metal salt to the collected abrasive slurry in the separation container.

5. The method of claim 1 , wherein the polished object comprises silicon.

6. The method of claim 1 wherein the glass is selected from the group consisting of optical glasses, glass substrates for information storage mediums, semiconductor silicon substrates, and glass plates of liquid crystal displays.

Assignees

• Konica Minolta Inc

Inventors

• Takahashi Atsushi
• Nagai Yuuki
• Maezawa Akihiro

Classifications

• B01D11/0246

  comprising rotating means · CPC title

• B01D21/02

  Settling tanks {with single outlets for the separated liquid} · CPC title

• B24B57/02 Primary

  for feeding of fluid, sprayed, pulverised, or liquefied grinding, polishing or lapping agents · CPC title

• B01D2221/14

  Separation devices for workshops, car or semiconductor industry, e.g. for separating chips and other machining residues · CPC title

• C09K3/1409 Primary

  Abrasive particles per se (preparation of diamond C01B32/25) · CPC title