PED: pressurized electroosmotic dewatering

Technical Report · Tue Oct 01 00:00:00 EDT 1985

OSTI ID:5069331

Heath, L W

Mechanical solid/liquid separation or dewatering of fine-grained suspensions is difficult to accomplish with any degree of success, cost effectiveness and/or practicality. The use of electroosmosis, the electrokinetic transport of water, which is theoretically independent of pore size, on the other hand can be quite slow and consume a great deal of electrical energy. However, in combining pressure and electroosmosis, an effective dewatering process is realized because the strength of each dewatering process is the weakness in the other and the combination of the two processes has no ill effect on each other. The strength of electroosmosis is in its independence of pore size, whereas pressure removes the free water from the larger pores rapidly and causes consolidation to occur. The experimental program investigated the optimization of pressurized electroosmotic dewatering (PED) of ultra-fine coal suspensions. The slurry characteristics of greatest interest were the particle size distribution and zeta potential. The particle size distribution controls the maximum packing density and thus, the lowest pore volume, obtainable. A reduction in pore volume increases the degree of saturation for a given quantity of water. The zeta potential of a suspension directly governs the electroosmotic flow rate. A computerized data acquisition system was built to monitor the PED tests. This enhanced the research by allowing more test data to be obtained in a short time and more testing to be completed because of the reduced test analysis time. Also, other suspended materials such as kaolinite slurries, lignite slurries, phosphate slimes, red mud, fly ash scrubber slimes and diamond slimes were tested using PED. The test results provide a basis for pilot-scale testing of PED in a continuous manner. 15 refs.

• Research Organization: Ames Lab., IA (USA)
• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 5069331
• Report Number(s): IS-T-1223; ON: DE86002108
• Resource Relation: Other Information: Portions of this document are illegible in microfiche products. Thesis
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
COAL FINES
OSMOSIS
PARTICLE SIZE
WATER REMOVAL
COAL PREPARATION
FUEL SLURRIES
PRESSURE DEPENDENCE
TIME DEPENDENCE
COMPUTERS
DATA ACQUISITION SYSTEMS
DENSITY
ELECTROPHORESIS
EXPERIMENTAL DATA
FLY ASH
MIXTURES
OPTIMIZATION
WATER
AEROSOL WASTES
ASHES
DATA
DIFFUSION
DISPERSIONS
FUELS
HYDROGEN COMPOUNDS
INFORMATION
NUMERICAL DATA
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
REMOVAL
RESIDUES
SIZE
SLURRIES
SUSPENSIONS
WASTES
013000* - Coal
Lignite
& Peat- Transport
Handling
& Storage