Washing method of goethite-containing red mud

Patent metadata

Field	Value
Publication number	US-9533891-B2
Application number	US-201314113421-A
Country	US
Kind code	B2
Filing date	Apr 5, 2013
Priority date	Apr 26, 2012
Publication date	Jan 3, 2017
Grant date	Jan 3, 2017

Abstract

A washing method of red mud that is produced when an alumina-containing ore having a goethite to hematite mass ratio of 60/40 (goethite/hematite) or more in the iron component thereof is heat-treated with an alkaline solution at a temperature of 110° C. to 160° C. to obtain an aluminate liquor, including: mixing the red mud with a diluting fluid to obtain suspension that has an aluminum concentration of 95 g/L or less in terms of Al 2 O 3 ; adding a flocculant to the suspension, wherein, the flocculant includes a polymer having a repeating unit derived from (meth)acrylic acid or a salt thereof and being substantially free from a repeating unit derived from vinylhydroxamic acid compound or a salt thereof; and settling and separating the red mud so as to wash the red mud.

First claim

The invention claimed is:

1. A washing method of red mud that is produced when an alumina-containing ore having a goethite to hematite mass ratio of 60/40 (goethite/hematite) or more in the iron component thereof is heat-treated with an alkaline solution at a temperature of 110° C. to 160° C. to obtain an aluminate liquor, comprising:
repeating a process, the process comprising mixing the red mud with a diluting fluid to obtain a suspension, adding a flocculant to the suspension, and settling and separating the red mud;
wherein, in at least one of the process repetitions, a concentration of aluminum in the suspension is more than 95 g/L in terms of Al 2 O 3 , and the flocculant comprises a polymer having a repeating unit derived from a vinylhydroxamic acid compound or a salt thereof, and
wherein, in at least one of the process repetitions, a concentration of aluminum in the suspension is 95 g/L or less in terms of Al 2 O 3 , and the flocculant comprises a polymer having a repeating unit derived from (meth)acrylic acid or a salt thereof and being substantially free from a repeating unit derived from a vinylhydroxamic acid compound or a salt thereof.

2. The washing method of red mud according to claim 1 ,
wherein, in at least one of the process repetitions, a concentration of aluminum in the suspension is 95 g/L or less in terms of Al 2 O 3 and a concentration of alkali in the suspension ranges from 30 g/L to 200 g/L in terms of NaOH, and the flocculant comprises a polymer having an anionization degree of 70 mole % to 100 mole % and having a repeating unit derived from (meth)acrylic acid or a salt thereof and being substantially free from a repeating unit derived from vinylhydroxamic acid compound or a salt thereof.

3. The washing method of red mud according to claim 1 ,
wherein, in at least one of the process repetitions, a concentration of aluminum in the suspension is 95 g/L or less in terms of Al 2 O 3 and a concentration of alkali in the suspension is 35 g/L or less in terms of NaOH, and the flocculant comprises a polymer having an anionization degree of 70 mole % to 100 mole % and having a repeating unit derived from (meth)acrylic acid or a salt thereof and being substantially free from a repeating unit derived from vinylhydroxamic acid compound or a salt thereof.

4. A method of producing red mud by a washing method according to claim 1 ,
wherein, the red mud has a level of concentration to solid of 600 g/L or more.

Assignees

• Showa Denko Kk

Inventors

• Akama Yu

Classifications

• C01F7/066

  Treatment of the separated residue · CPC title

• C02F2103/10

  from quarries or from mining activities · CPC title

• B03D3/06

  Flocculation · CPC title

• C22B3/00

  Extraction of metal compounds from ores or concentrates by wet processes · CPC title

• C02F1/56

  Macromolecular compounds · CPC title