Method for treating water that circulates through wet paint booth

Patent metadata

Field	Value
Publication number	US-10745302-B2
Application number	US-201716087785-A
Country	US
Kind code	B2
Filing date	Mar 24, 2017
Priority date	Mar 31, 2016
Publication date	Aug 18, 2020
Grant date	Aug 18, 2020

Abstract

To efficiently perform an adhesion reduction treatment of water that circulates through a wet paint booth which contains a solvent-based paint by adding a relatively small amount of chemical to the water without the need for another chemical except that the alkaline chemical is used for pH adjustment, that is, with only one chemical. An aluminum salt having a basicity of 60% or more and an alkaline chemical are added to water that circulates through a wet paint booth which contains a solvent-based paint. An adhesion reduction treatment of the solvent-based paint is performed at a pH of 7 or more and is preferably performed at a pH of 7.5 or more. Using a powder mixture produced by mixing a powder of the aluminum salt with a powder of the alkaline chemical facilitates the treatment.

First claim

The invention claimed is:

1. A method for treating water that circulates through a wet paint booth, the water containing a solvent-based paint, the method comprising:
adding additives consisting of an aluminum salt and an alkaline chemical to the water that circulates through the wet paint booth, to adjust a pH of the water that circulates through the wet paint booth to be 7 or more, the aluminum salt containing basic aluminum chloride and having a basicity of 60% or more and a mass ratio Al/Cl of aluminum to chlorine being 1.0 or more, and
allowing for precipitation and flocculation of the aluminum salt, thereby reducing adhesiveness of the solvent-based paint.

2. The method for treating water that circulates through a wet paint booth according to claim 1 , wherein the aluminum salt is a basic aluminum chloride.

3. The method for treating water that circulates through a wet paint booth according to Claim 1 , wherein a powder mixture produced by mixing a powder of the aluminum salt with a powder of the alkaline chemical is added to the water that circulates through the wet paint booth, and wherein a mixing ratio between the powder of the aluminum salt and the powder of the alkaline chemical is adjusted such that the water that circulates through the wet paint booth has a pH of 7 or more after the mixture has been added to the water.

4. A method for treating water that circulates through a wet paint booth according to claim 1 , wherein the mass ratio Al/Cl of aluminum to chlorine is 2.0 or less.

5. A method for treating water that circulates through a wet paint booth according to claim 4 , wherein the aluminum salt forms flocs having an average size of 2 μm.

Assignees

• Kurita Water Ind Ltd

Inventors

• Arimoto Yuta

Classifications

• C02F2103/14

  Paint wastes · CPC title

• C02F2209/06

  pH · CPC title

• B01D21/01

  using flocculating agents (for purifying water C02F1/52; for liquid radioactive waste G21F9/10) · CPC title

• C02F1/66

  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) · CPC title

• B01D21/305

  Control of chemical properties of a component, e.g. control of pH · CPC title