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Utilizing mixed-mineralogy ferroan magnesite tailings as the source of magnesium oxide in magnesium potassium phosphate cement

Research output: Contribution to journalArticleScientificpeer-review

Details

Original languageEnglish
Article number117098
JournalConstruction and building materials
Volume231
Early online date9 Oct 2019
DOIs
Publication statusE-pub ahead of print - 9 Oct 2019
Publication typeA1 Journal article-refereed

Abstract

A mixed-mineralogy talc mine tailing (MT) fraction consisting of 80% ferroan magnesite (MgCO3) was studied for utilization as the source of magnesium oxide (MgO) in magnesium potassium phosphate cement (MKPC). The effects of calcination temperature of this low-grade magnesite on the composition, BET surface area and phosphate reactivity of the resulting magnesia powder were studied. The 4-point flexural strength of resulting MKPC was measured for all calcined raw material fractions that produced a solid. Based on the strength measurement results, the optimal range for calcination resided between 700 °C and 1150 °C, which is drastically lower than commonly recommended for finer magnesia sources in MKPCs. Accelerated reactivity assessment showed that phosphate reactivity behavior could not be entirely predicted by BET surface area. The presence of impurity silicates and high iron content in all the constituent minerals was posed as the reason for densification and loss of reactivity at higher calcination temperatures.

Keywords

  • Bending strength, Chemically bonded ceramics, MgO, Mixed-mineralogy, pH, Phosphate cement, Surface area

Publication forum classification

Field of science, Statistics Finland