Process for removing metal ions from liquids

US5447603A · kind A · utility

Assignee

• THE DOW CHEMICAL COMPANY · US

Inventors

• Robert J. Michalowski · Midland, US
• Steven H. Christiansen · Lake Jackson, US
• R. Keith Frank · Lake Jackson, US
• Teresa Littleton · Lake Jackson, US
• Jaime Simon · Angleton, US
• Walter L. Vaughn · Lake Jackson, US
• David A. Wilson · Lake Jackson, US

Key dates

• Filing date: Jul 9, 1993
• Grant date: Sep 5, 1995
• Expiry date: Jul 9, 2013

Classification

• Technology area (CPC D): Textiles; Paper
• CPC primary: D21C9/1042
• WIPO field: Textile and paper machines
• WIPO sector: Mechanical engineering

Abstract

The invention is an improvement in a process for making cellulosic articles said process involving a separation of cellulosic material from a mixture containing a liquid, metal cations, and cellulosic material. The improvement involves adding to the mixture at least one retaining material which binds at least one metal cation and, in the separation, is retained with the cellulosic material. Suitable retaining agents are either organic or inorganic and include chelate-forming polymers, both synthetic and natural, colloidal suspensions of inorganic compounds, and mixed metal hydroxides. In each case, the metal cations remain in the cellulosic article, e.g. paper, rather going into waste water from which they would otherwise need to be removed.