Multi-step process for concentrating magnetic particles in waste sludges

Patent · Mon Jan 01 04:00:00 EST 1990

OSTI ID:867451

Watson, John L ^[1]

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1. Rolla, MO

This invention involves a multi-step, multi-force process for dewatering sludges which have high concentrations of magnetic particles, such as waste sludges generated during steelmaking. This series of processing steps involves (1) mixing a chemical flocculating agent with the sludge; (2) allowing the particles to aggregate under non-turbulent conditions; (3) subjecting the mixture to a magnetic field which will pull the magnetic aggregates in a selected direction, causing them to form a compacted sludge; (4) preferably, decanting the clarified liquid from the compacted sludge; and (5) using filtration to convert the compacted sludge into a cake having a very high solids content. Steps 2 and 3 should be performed simultaneously. This reduces the treatment time and increases the extent of flocculation and the effectiveness of the process. As partially formed aggregates with active flocculating groups are pulled through the mixture by the magnetic field, they will contact other particles and form larger aggregates. This process can increase the solids concentration of steelmaking sludges in an efficient and economic manner, thereby accomplishing either of two goals: (a) it can convert hazardous wastes into economic resources for recycling as furnace feed material, or (b) it can dramatically reduce the volume of waste material which must be disposed.

• Research Organization: BATTELLE MEMORIAL INSTITUTE
• DOE Contract Number: AC06-76RL01830
• Assignee: Curators of University of Missouri (Columbia, MO)
• Patent Number(s): US 4940550
• OSTI ID: 867451
• Country of Publication: United States
• Language: English

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