# US 9,751,783 B2 · Method for a treatment for wastewater containing aluminum, magnesium, and manganese

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- Number: US 9,751,783 B2
- Document ID: US9751783B2
- Status: Granted
- Kind: B2
- Application number: 13/583,145
- Filed: 2011-01-06
- Published: 2013-01-03
- Granted: 2017-09-05
- Earliest claimed: 2010-03-10
- Assignees: Sumitomo Mental Mining Co., Ltd.
- Applicants: Hiroshi Kobayashi; Tatsuya Higaki; Hirofumi Shoji; Norihisa Toki; Keiji Kudo; Hiroyuki Mitsui; Osamu Nakai
- Inventors: Hiroshi Kobayashi; Tatsuya Higaki; Hirofumi Shoji; Norihisa Toki; Keiji Kudo; Hiroyuki Mitsui; Osamu Nakai
- Web page: https://patentgrep.com/patent/US9751783B2

## CPC

- C02F 1/66: by neutralisation; pH adjustment (for degassing C02F1/20; using ion-exchange C02F1/42; for flocculation or precipitation of suspended impurities C02F1/52; for removing dissolved compounds C02F1/58)
- C01G 45/02: Oxides
- C02F 1/5236: {using inorganic agents}
- C02F 1/64: of iron or manganese
- C02F 1/722: {Oxidation by peroxides}
- C02F 1/78: with ozone {(C02F1/4672 takes precedence)}
- C02F 1/72: by oxidation {(C02F1/4672 takes precedence)}
- C02F 2101/20: Heavy metals or heavy metal compounds
- C02F 2101/206: {Manganese or manganese compounds}
- C02F 2209/06: pH
- C22B 47/00: Obtaining manganese
- Y02P 10/20: Recycling
- C02F: TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE (separation in general B01D; special arrangements on waterborne vessels of installations for treating water, waste water or sewage, e.g. for producing fresh water, B63J; adding materials to water to prevent corrosion C23F; treating radioactively-contaminated liquids G21F9/04; regeneration of reactants for recirculation into processes, see the relevant places for the processes)
- 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)
- C22B: PRODUCTION AND REFINING OF METALS (electrolytic C25); PRETREATMENT OF RAW MATERIALS
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

The wastewater treatment method is to obtain demanganized wastewater, through a step wherein an acid or an alkali is added to sulfuric acid acidified wastewater to adjust pH to not less than 4.0 and not more than 6.0, whereby the sulfuric acid acidified wastewater is separated into a dealuminized solution and an aluminum precipitate; a step wherein a slurrying solution is added to the aluminum precipitate to form a slurry, then an alkali is added to adjust pH to not less than 9.0 and not more than 9.5, whereby an pH-adjusted aluminum precipitate slurry is formed; a step wherein an alkali is added to the dealuminized solution to adjust pH to not less than 8.0 and not more than 9.0; and others.

## Claims

### Claim 1

A wastewater treatment method for obtaining demanganized wastewater from sulfuric acid acidified wastewater obtained by processing nickel oxide ore and containing aluminum, magnesium, and manganese, comprising:
adjusting the pH of the sulfuric acid acidified wastewater to not less than 4.0 and not more than 5.0 by adding an acid or alkali;
precipitating aluminum;
preventing coprecipitation of magnesium with aluminum; and then
separating the pH adjusted sulfuric acid acidified wastewater into a dealuminized solution that includes magnesium and manganese and has an aluminum concentration of not more than 0.1 g/L, and an aluminum hydroxide precipitate that includes adhering water and is represented as [Al(OH)3];
admixing water and the aluminum hydroxide precipitate to form an aluminum slurry;
adjusting a pH of this aluminum slurry to not less than 9.0 and not more than 9.5; thereby
forming a pH-adjusted aluminum precipitate slurry including a stabilized aluminum hydroxide precipitate that does not form a precipitate with magnesium; and then
separating the pH-adjusted aluminum precipitate slurry into the stabilized aluminum hydroxide precipitate and a filtrate including manganese;
adjusting a pH of the dealuminized solution to a range of not less than 8.0 and not more than 9.0,
adding an oxidizing agent to the dealuminized solution;
forming an oxidized and neutralized slurry that includes a trivalent manganese; and then
solid-liquid separating the oxidized and neutralized slurry into a trivalent manganese precipitate and demanganized wastewater,
wherein the stabilized aluminum hydroxide precipitate, the filtrate including manganese, and the demanganized wastewater are usable as an alkali used for adjustment of the pH of the sulfuric acid acidified wastewater.

### Claim 2 (depends on 1)

The wastewater treatment method according to claim 1, wherein the pH of the sulfuric acid acidified wastewater is adjusted by the addition of an alkali selected from the group consisting of the aluminum hydroxide precipitate, the filtrate, the demanganized wastewater, calcium carbonate, calcium hydroxide, calcium oxide, slaked lime, sodium hydroxide, potassium hydroxide, and a mixture thereof.

### Claim 3 (depends on 1)

The wastewater treatment method according to claim 1, wherein the oxidized and neutralized slurry is admixed with the pH-adjusted aluminum precipitate slurry or the aluminum slurry; and then solid-liquid separating this admixture into the trivalent manganese precipitate and the demanganized wastewater.

### Claim 4 (depends on 1)

The wastewater treatment method according to claim 1, wherein the oxidizing agent is selected from the group consisting of air, ozone gas, a hydrogen peroxide solution, sulfur dioxide gas, oxygen, and a mixture thereof.

### Claim 5 (depends on 1)

The wastewater treatment method according to claim 1, wherein an oxidizing agent is admixed with the dealuminized solution and this admixture is stored in a pressure vessel.

### Claim 6 (depends on 1)

The wastewater treatment method according to claim 1, wherein the sulfuric acid acidified wastewater is obtained in such a manner that nickel and cobalt, each contained in a nickel oxide ore, are leached with sulfuric acid by high-pressure acid leaching, and a thus obtained sulfuric acid acidified solution is neutralized to separate impurities, and then is sulfurized to separate nickel and cobalt as a sulfide precipitate.

### Claim 7 (depends on 1)

The wastewater treatment method according to claim 1, wherein the pH of the sulfuric acid acidified wastewater, the aluminum slurry, and/or the dealuminized solution is adjusted by addition of the filtrate.

### Claim 8 (depends on 1)

The wastewater treatment method according to claim 1, wherein the method forms demanganized wastewater without precipitating magnesium.

### Claim 9 (depends on 1)

The wastewater treatment method according to claim 1, wherein the alkali used for adjustment of the pH of the sulfuric acid acidified wastewater is the stabilized aluminum hydroxide precipitate, the filtrate including manganese, and/or the demanganized wastewater.