# US 2021/0276879 A1 · Method of Preparing Indium Oxide Spherical Powder With Controllable Grain Shape

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2021/0276879 A1
- Document ID: US20210276879A1
- Status: Published application
- Kind: A1
- Application number: 15/931,269
- Filed: 2020-05-13
- Published: 2021-09-09
- Earliest claimed: 2020-03-06
- Assignees: Zhengzhou University
- Applicants: Zhengzhou University
- Inventors: Jie CHEN; Jilin HE; Benshuang SUN; Yongchun SHU; Xueyun ZENG; Yang LIU
- Web page: https://patentgrep.com/patent/US20210276879A1

## CPC

- C01G 15/00: Compounds of gallium, indium or thallium
- C01P 2002/70: defined by measured X-ray, neutron or electron diffraction data
- C01P 2002/72: by d-values or two theta-values, e.g. as X-ray diagram
- C01P 2004/03: obtained by SEM
- C01P 2004/04: obtained by TEM, STEM, STM or AFM
- C01P 2004/32: Spheres
- C01P 2004/61: Micrometer sized, i.e. from 1-100 micrometer
- C01P 2004/62: Submicrometer sized, i.e. from 0.1-1 micrometer
- C01G: COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F (metal hydrides {monoborane, diborane or addition complexes thereof} C01B6/00; salts of oxyacids of halogens C01B11/00; peroxides, salts or peroxyacids C01B15/00; thiosulfates, dithionites, polythionates C01B17/64; compounds containing selenium, or tellurium C01B19/00; binary compounds of nitrogen with metals C01B21/06; azides C01B21/08; {compounds containing nitrogen, other non-metals and metal C01B21/082}; metal amides C01B21/092; nitrites C01B21/50; {compounds of noble gases C01B23/0005}; phosphides C01B25/08; salts of oxyacids of phosphorus C01B25/16; carbides C01B32/90; compounds containing silicon C01B33/00; compounds containing boron C01B35/00; compounds having molecular sieve properties but not having base-exchange properties C01B37/00; compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites, C01B39/00; cyanides C01C3/08; salts of cyanamide C01C3/16; thiocyanates C01C3/20)
- C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS

## Abstract

A method of preparing an indium oxide spherical powder with a controllable grain shape includes: (1) reacting a sulfuric acid solution, and then adding a nitric acid solution, to react with the metal indium to obtain a mixed solution system containing indium sulfate and indium nitrate; (2) adjusting a concentration of indium ions in the mixed solution system to between 0.45˜0.6M; (3) performing a precipitation reaction of the mixed solution with a precipitant, until a pH value of the solution is between 9-10, and then having the solution precipitated and aged to obtain an indium hydroxide precursor slurry; (4) using a ceramic membrane to filter and wash the precursor slurry, and ending the washing to obtain a purified precursor sample; (5) drying the precursor sample at 80˜130° C.; and (6) ball-milling the precursor sample, and calcining the precursor at a calcination temperature to obtain the indium oxide powder.

## Claims

### Claim 1

A method of preparing an indium oxide spherical powder with a controllable grain shape, comprising:
(1) reacting a sulfuric acid solution, which has a concentration of 35˜50%, with metal indium for a certain period of time, and then adding a nitric acid solution, which has a concentration of 65˜68%, to react with the metal indium to obtain a mixed solution system containing indium sulfate and indium nitrate;
(2) adjusting a concentration of indium ions in the mixed solution system between 0.45˜0.6M;
(3) performing a precipitation reaction of the mixed solution system with a certain concentration of precipitant until a pH value of the solution system is between 9˜10, and then precipitating and aging the solution system for a certain time to obtain an indium hydroxide precursor slurry;
(4) using a ceramic membrane to filter and wash the precursor slurry, until a pH value of a washed filtrate is between 7˜8 and its conductivity is less than or equal to 50 μS/cm, and ending the washing to obtain a purified precursor sample;
(5) drying the purified precursor sample at 80˜130° C.; and
(6) ball-milling the dried precursor sample, and then calcining the ball-milled precursor at a set calcination temperature to obtain the indium oxide powder.

### Claim 2 (depends on 1)

The method of preparing an indium oxide spherical powder with a controllable grain shape according to claim 1, wherein volume ratio of the nitric acid solution to the sulfuric acid solution is set to 2:1˜1:1.

### Claim 3 (depends on 1)

The method of preparing an indium oxide spherical powder with a controllable grain shape according to claim 1, wherein based on a mass of the metal indium, an addition rate of the nitric acid solution is controlled between 0.1˜0.6 ml/min/g.

### Claim 4 (depends on 1)

The method of preparing an indium oxide spherical powder with a controllable grain shape according to claim 1, wherein the reacting a sulfuric acid solution and then the adding a nitric acid solution, comprises:
(1-1) cutting an appropriate amount of the metal indium into small pieces and putting them in a container;
(1-2) adding the sulfuric acid solution, and controlling a reaction temperature between 70˜95° C.;
(1-3) after an interval of 3˜10 minutes, adding the nitric acid solution at a set rate, and controlling the reaction temperature between 60˜75° C.;
(1-4) when reaction is gentle, stirring to obtain a uniform mixed solution system.

### Claim 5 (depends on 4)

The method of preparing an indium oxide spherical powder with a controllable grain shape according to claim 4, wherein the container includes high borosilicate glass as its inner wall material.

### Claim 6 (depends on 1)

The method of preparing an indium oxide spherical powder with a controllable grain shape according to claim 1, wherein ammonia water is selected as the precipitant, a concentration of the ammonia water is set to 25˜27%, temperature of the precipitation reaction is controlled between 25˜45° C., and time for precipitating and aging is set to 10˜24 hours

### Claim 7 (depends on 1)

The method of preparing an indium oxide spherical powder with a controllable grain shape according to claim 1, wherein a ball mill rotating speed for ball-milling the precursor sample is set to 180˜300 rpm, and a ball-milling time is set to 15˜35 hours.

### Claim 8 (depends on 1)

The method of preparing an indium oxide spherical powder with a controllable grain shape according to claim 1, wherein a soaking time for calcination of the ball-milled precursor powder material is set to 3˜7 hours.

### Claim 9 (depends on 1)

The method of preparing an indium oxide spherical powder with a controllable grain shape according to claim 1, wherein a heating rate to the calcination temperature is set to 3˜5° C./min.