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Title: Aggregation and colloidal stability of fine-particle coal suspensions

Abstract

The aggregation and colloidal stability of colloidal coal suspensions in the presence of varying concentrations of hydrogen ions, neutral salts, and aluminum sulfate were investigated. Critical concentration and critical pH values for coagulation and stabilization were determined from turbidity changes during settling following aggregation. Two colloidal suspensions of a bituminous coal representing stability extremes due to oxidation were compared. In the absence of other coagulants, vigorous oxidation lowered the isoelectric point of the coal sol from pH 5.1 to pH 1.1 and the pH for stabilization from 7.5 to 2.6. The coagulation of the suspensions followed the Schulze-Hardy rule as hydrophobic sols although the oxidized coal sol was slightly less sensitive to neutral salts. The entire log aluminum sulfate concentration-pH stability limit diagram for the oxidized coal sol was established. The boundaries of settling of the coal in the presence of aluminum sulfate were similar to other hydrophobic sols except for small differences in alkaline solution. Regions of ionic coagulation, rapid coagulation due to enmeshment in aluminum hydroxide precipitate, and restabilization were also observed and delineated.

Authors:
;
Publication Date:
Research Org.:
Ohio State Univ., Columbus
OSTI Identifier:
6844284
Resource Type:
Journal Article
Journal Name:
Environ. Sci. Technol.; (United States)
Additional Journal Information:
Journal Volume: 18:4
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; BITUMINOUS COAL; OXIDATION; SUSPENSIONS; AGGLOMERATION; FLOCCULATION; STABILITY; ALUMINIUM SULFATES; COLLOIDS; HYDROGEN IONS; PH VALUE; SALTS; ALUMINIUM COMPOUNDS; BLACK COAL; CARBONACEOUS MATERIALS; CHARGED PARTICLES; CHEMICAL REACTIONS; COAL; DISPERSIONS; ENERGY SOURCES; FOSSIL FUELS; FUELS; IONS; MATERIALS; OXYGEN COMPOUNDS; PRECIPITATION; SEPARATION PROCESSES; SULFATES; SULFUR COMPOUNDS; 010600* - Coal, Lignite, & Peat- Properties & Composition

Citation Formats

Schroeder, P R, and Rubin, A J. Aggregation and colloidal stability of fine-particle coal suspensions. United States: N. p., 1984. Web. doi:10.1021/es00122a011.
Schroeder, P R, & Rubin, A J. Aggregation and colloidal stability of fine-particle coal suspensions. United States. https://doi.org/10.1021/es00122a011
Schroeder, P R, and Rubin, A J. 1984. "Aggregation and colloidal stability of fine-particle coal suspensions". United States. https://doi.org/10.1021/es00122a011.
@article{osti_6844284,
title = {Aggregation and colloidal stability of fine-particle coal suspensions},
author = {Schroeder, P R and Rubin, A J},
abstractNote = {The aggregation and colloidal stability of colloidal coal suspensions in the presence of varying concentrations of hydrogen ions, neutral salts, and aluminum sulfate were investigated. Critical concentration and critical pH values for coagulation and stabilization were determined from turbidity changes during settling following aggregation. Two colloidal suspensions of a bituminous coal representing stability extremes due to oxidation were compared. In the absence of other coagulants, vigorous oxidation lowered the isoelectric point of the coal sol from pH 5.1 to pH 1.1 and the pH for stabilization from 7.5 to 2.6. The coagulation of the suspensions followed the Schulze-Hardy rule as hydrophobic sols although the oxidized coal sol was slightly less sensitive to neutral salts. The entire log aluminum sulfate concentration-pH stability limit diagram for the oxidized coal sol was established. The boundaries of settling of the coal in the presence of aluminum sulfate were similar to other hydrophobic sols except for small differences in alkaline solution. Regions of ionic coagulation, rapid coagulation due to enmeshment in aluminum hydroxide precipitate, and restabilization were also observed and delineated.},
doi = {10.1021/es00122a011},
url = {https://www.osti.gov/biblio/6844284}, journal = {Environ. Sci. Technol.; (United States)},
number = ,
volume = 18:4,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 1984},
month = {Sun Jan 01 00:00:00 EST 1984}
}