Vacuum and pressure expression dewatering of fine coal and refuse using a belt filter press

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1988

OSTI ID:7035531

Badgujar, M N

Vacuum dewatering was found to be sufficient for coarse size fractions of fine coal (top size 400 mesh) and vacuum plus pressure expression dewatering was effective only for the ultra-fine coal (average size 10 {mu}m). For fine coal refuse however, both vacuum and pressure expression were observed to be necessary to obtain better cake filterability and lower cake moisture content. Several flocculants having different ionic activities, molecular weights and chemical compositions were tested. For fine coal refuse, nonionic flocculants in the medium molecular weight range of 4-5 million were found to be most effective in terms of lower cake formation time (filterability) and final moisture content. The performance of an anionic flocculant in the same molecular weight range was not as good as the nonionic flocculant. In the higher molecular weight range (10-15 million) the effect of ionic properties was negligible and all three types (anionic, cationic, nonionic) were equally effective. The effect of mixing conditions on flocculation of coal refuse slurry was investigated for selected flocculants. The effect of surfactants on the final moisture content of coal refuse cake was significant. The effect of belt speed on final moisture content was negligible indicating that expression was complete even at higher speeds. The effects of solid addition and solids concentration, on final moisture content and cake formation time were investigated. The compressive force present in the belt filter press was measured by various techniques including a miniature pressure transducer, pressure sensitive film and force sensing resistors. An empirical correlation for estimation of actual pressure as a function of applied hydraulic pressure was developed.

• Research Organization: Pittsburgh Univ., PA (USA)
• OSTI ID: 7035531
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010300* -- Coal
Lignite
& Peat-- Preparation-- (1987-)
010800 -- Coal
Lignite
& Peat-- Waste Management
ADDITIVES
CHEMICAL COMPOSITION
COAL FINES
COMPRESSION
DISPERSIONS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
FILTERS
FILTRATION
FLOCCULATION
IONIC CONDUCTIVITY
LOW PRESSURE
MIXTURES
MOLECULAR WEIGHT
PERFORMANCE TESTING
PHYSICAL PROPERTIES
PRECIPITATION
PRESSES
PRESSURE DEPENDENCE
REMOVAL
SEPARATION EQUIPMENT
SEPARATION PROCESSES
SLURRIES
SOLID WASTES
SURFACTANTS
SUSPENSIONS
TAILINGS
TESTING
WASTES
WATER REMOVAL