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Effects of pH, Temperature, and Water Quality on Chloride Removal with Ultra‐High Lime with Aluminum Process
Author(s) -
AbdelWahab Ahmed,
Batchelor Bill
Publication year - 2006
Publication title -
water environment research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.356
H-Index - 73
eISSN - 1554-7531
pISSN - 1061-4303
DOI - 10.2175/106143005x72821
Subject(s) - chloride , chemistry , sulfate , lime , water treatment , aluminium , inorganic chemistry , nuclear chemistry , materials science , waste management , metallurgy , organic chemistry , engineering
The ultra high‐lime with aluminum process (UHLA) has the ability to remove sulfate and chloride in addition to other scale‐forming materials from recycled cooling water. Laboratory experiments have demonstrated that the UHLA process can achieve high chloride removal from recycled cooling water, and an equilibrium model was developed to describe chemical behavior during chloride removal. This paper describes the influence of pH, temperature, and initial chloride concentration on chloride removal by UHLA and identifies the precipitated solids formed during treatment. The optimum pH for maximum chloride removal efficiency was found to be 12 ± 0.2. Chloride removal efficiency was higher at a high initial chloride concentration than at a low initial chloride concentration with the chemical doses used. Solids formed during UHLA treatment were identified by x‐ray diffraction as calcium chloroaluminate, tricalcium hydroxyaluminate, and tetracalcium hydroxyaluminate. This supports the assumption of the equilibrium model that these compounds are present and form a solid solution.