Interactions between chloride and sulfate or silica removals from wastewater using an advanced lime-aluminum softening process: Equilibrium modeling

Ahmed Abdel-Wahab, Bill Batchelor

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Interactions among chloride, sulfate, and silica removals from recycled industrial wastewater using an ultra-high lime with aluminum process (UHLA) were studied. An equilibrium model that is able to accurately predict the chemical behavior and interactions between chloride and sulfate or silica with UHLA at various initial conditions and chemical reagents was developed. X-ray diffraction (XRD) analysis was conducted to identify the precipitated solids formed in the UHLA process. Model predictions indicated that simultaneous removal of sulfate and chloride can be best described by the formation of a solid solution containing calcium chloroaluminate, calcium sulfoaluminate (ettringite), calcium monosulfate, tricalcium hydroxyaluminate, and tetracalcium hydroxyaluminate. However, simultaneous removal of silica and chloride can be best described by precipitation of calcium silicate and calcium aluminosilicate in addition to a solid solution containing calcium chloroaluminate, tricalcium hydroxyaluminate, and tetracalcium hydroxyaluminate. The XRD results indicated the presence of the same solids assumed by the equilibrium model.

Original languageEnglish
Pages (from-to)528-535
Number of pages8
JournalWater Environment Research
Volume79
Issue number5
DOIs
Publication statusPublished - 1 Jan 2007
Externally publishedYes

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Keywords

  • Brine
  • Chloride removal
  • Cooling water
  • Equilibrium modeling
  • Industrial wastewater
  • Silica removal
  • Softening
  • Solid solution
  • Sulfate removal

ASJC Scopus subject areas

  • Environmental Chemistry
  • Water Science and Technology

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