Phosphorus and calcium collection method, and mixture produced by said collection method

Patent metadata

Field	Value
Publication number	US-2016347615-A1
Application number	US-201415114719-A
Country	US
Kind code	A1
Filing date	Nov 11, 2014
Priority date	Jan 28, 2014
Publication date	Dec 1, 2016
Grant date	—

Abstract

An aqueous solution containing 30 ppm or more of carbon dioxide is brought into contact with a steel-making slag to elute phosphorus and calcium contained in the steel-making slag into the aqueous solution. Subsequently, carbon dioxide is removed from the aqueous solution to precipitate a mixture comprising a phosphorus compound and a calcium compound. In this manner, a mixture comprising a phosphorus compound and a calcium compound and containing phosphorus in an amount of 1% by mass or more in terms of phosphorus atom content can be produced.

First claim

1 . A method of recovering phosphorus and calcium from steelmaking slag, comprising:
bringing the steelmaking slag in contact with an aqueous solution containing 30 ppm or more of carbon dioxide to elute phosphorus and calcium contained in the steelmaking slag into the aqueous solution; and subsequently, removing the carbon dioxide from the aqueous solution to precipitate a mixture containing a phosphorus compound and a calcium compound.

2 . The method of recovering phosphorus and calcium according to claim 1 , wherein: the removing of the carbon dioxide includes:
partly removing the carbon dioxide from the aqueous solution to precipitate the mixture; and subsequently, further removing the carbon dioxide from the aqueous solution to precipitate the mixture, and a proportion of the phosphorus compound in the mixture obtained in the further removing of the carbon dioxide is less than a proportion of the phosphorus compound in the mixture obtained in the partly removing of the carbon dioxide.

3 . The method of recovering phosphorus and calcium according to claim 2 , wherein a precipitation rate of the mixture in the partly removing of the carbon dioxide is 0.1 g/min·L or less.

4 . The method of recovering phosphorus and calcium according to claim 1 , wherein, in the removing of the carbon dioxide, the carbon dioxide is removed by blowing one or more gases selected from the group consisting of air, nitrogen, oxygen, hydrogen, argon and helium into the aqueous solution.

5 . The method of recovering phosphorus and calcium according to claim 4 , wherein, in the partly removing of the carbon dioxide, the one or more gases are intermittently blown into the aqueous solution.

6 . The method of recovering phosphorus and calcium according to claim 1 , wherein, in the removing of the carbon dioxide, the carbon dioxide is removed by reducing a pressure of the aqueous solution.

7 . The method of recovering phosphorus and calcium according to claim 1 , wherein, in the removing of the carbon dioxide, the carbon dioxide is removed by heating the aqueous solution.

8 . The mixture obtained by the method of recovering phosphorus and calcium according to claim 1 , wherein
the mixture contains a phosphorus compound and a calcium compound, and the mixture contains 1 wt % or more of phosphorus in terms of atom.

Assignees

• Nisshin Steel Co Ltd

Inventors

• Matsuo Shoichi
• Asaba Akihiro
• Fukui Yasushi
• Yamamoto Masaya

Classifications

• C04B5/06

  Ingredients, other than water, added to the molten slag {or to the granulating medium or before remelting}; Treatment with gases or gas generating compounds, e.g. to obtain porous slag · CPC title

• C01B25/027

  of yellow phosphorus · CPC title

• C01B25/01 Primary

  Treating phosphate ores or other raw phosphate materials to obtain phosphorus or phosphorus compounds · CPC title

• C04B5/00

  Treatment of  {metallurgical}  slag  (manufacture of slag wool C03B; in, or for, the production of metals C21B, C22B); Artificial stone from molten  {metallurgical}  slag  {(other cast stone C04B32/005; mechanical aspects B28B1/54)} · CPC title

• C01B25/32

  Phosphates of magnesium, calcium, strontium, or barium · CPC title