The effect of temperature on coagulation and flocculation of aqueous coal suspensions

Thesis/Dissertation · Mon Jul 20 04:00:00 EDT 1992

OSTI ID:10178337

Van Bemmel, W

Objectives were to determine the stability of coal and kaolin suspensions as a function of temperature, and to see if the materials could be separated by changing the temperature either with or without a flocculant. Laboratory experiments showed that the stability tended to decrease with temperature and was pH dependent for both Colchester (Col) and No. 2 Gas Seal (GS) coals. Col coal suspensions flocculated more rapidly at 95 C when Triton N101 nonionic surfactant was present. Kaolin suspension stability was affected primarily by pH; heating to 70 C increased the settling rate at the pH where flocculation occurred at room temp (RT). Kaolin and Col coal were separated by heating to 95 C with Triton N101; optimum conditions were determined. Stagewise separation of 50/50 Col coal/kaolin mixture resulted in 71-86% coal recovery and 9-17% ash recovery after 3 stages. HPMC and PEO both increased the aggregation of Col coal suspensions upon heating. Mixtures of Col coal and kaolin heteroflocculated in presence of HPMC at RT. Coal was selectively flocculated by PEO at RT; the coal recovery increased as the solids concentration went from 1.6 to 4%; and heating the suspensions to 95 C with PEO increased the flocculation and in some cases decreased the separation efficiency. GS Coal was selectively coagulated at RT around pH 8; at 95 C, the coagulation occurred at pH 9. 26 figs, 27 refs. (DLC)

• Research Organization: Ames Lab., IA (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States); Department of the Interior, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 10178337
• Report Number(s): IS-T--1618; ON: DE92040580; CNN: Grant G1104119; Grant G1114119
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010300
COAL
FLOCCULATION
HEATING
KAOLIN
PH VALUE
PREPARATION
SEPARATION PROCESSES
SURFACTANTS
SUSPENSIONS
TEMPERATURE EFFECTS
TEMPERATURE RANGE 0273-0400 K