Effect of multivalent salts -- calcium and aluminum -- on the flocculation of kaolin suspension with anionic polyacrylamide

Journal Article · Fri Apr 01 04:00:00 EST 1994 · Journal of Colloid and Interface Science; (United States)

DOI:https://doi.org/10.1006/jcis.1994.1161· OSTI ID:7274659

Peng, F F; Di, P ^[1]

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1. West Virginia Univ., Morgantown, WV (United States). Dept. of Mineral Processing Engineering

The effects of calcium and aluminum ions on the interaction behavior of anionic polyacrylamide (anionic PAM or HPAM) and kaolin are important in determining the efficient flocculation of kaolin. While kaolin surfaces are negatively charged in media such as water, they exhibit the positive surface charge characteristic at pH below 3.2 in the solution of calcium cation, and at pH below 9.2 in the solution of aluminum cation. The. experimental results show that both calcium and aluminum ions suppress the kaolin flocculation process. The results are analyzed and explained by molecular orbital theory, solution chemistry, infrared spectra, and electronic probe examination of kaolin treated with and without anionic PAM. Analysis results indicate that the specific adsorption of Ca[sup 2+], Al[sup 3+] and their hydroxo complexes on anionic PAM causes the loss of anionic character in the low pH range and leads to a low flocculation efficiency. In the high pH range, the poor kaolin flocculation can be attributed to precipitation of calcium and aluminum hydroxides on active functional groups, which inhibits the hydrogen bonding between anionic PAM and kaolin surfaces. At neutral pH values, the trivalent aluminum ion has more significant adverse effect on the kaolin flocculation than the divalent calcium ion.

• OSTI ID: 7274659
• Journal Information: Journal of Colloid and Interface Science; (United States), Journal Name: Journal of Colloid and Interface Science; (United States) Vol. 164:1; ISSN 0021-9797; ISSN JCISA5
• Country of Publication: United States
• Language: English

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32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
320303* -- Energy Conservation
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& Utilization-- Industrial & Agricultural Processes-- Equipment & Processes
ADSORPTION
ALKALINE EARTH METALS
ALUMINIUM
CALCIUM
CATALYTIC EFFECTS
CLAYS
ELEMENTS
FLOCCULATION
KAOLIN
METALS
ORE PROCESSING
ORGANIC COMPOUNDS
ORGANIC POLYMERS
PH VALUE
POLYMERS
POTENTIALS
PRECIPITATION
PROCESSING
SEPARATION PROCESSES
SORPTION
SURFACE POTENTIAL
WATER TREATMENT