Evaluation of two white marbles for the correction of the aggressivity of fresh water of rivers

Abstract

In order to correct aggressive water destined for consumption by remineralization, the kinetics of dissolution of marble, an available material primarily made of calcite, were determined. Two types of marble were characterized by FTIR and X-ray spectroscopy and by chemical analysis, and then employed for the kinetics studies at room temperature and pH 1, 3 and 5, in synthetic solutions of hydrochloric acid diluted with distilled water. Dissolution was carried out in agitated reactor at 105 rpm; in which were plunged electrodes for pH and conductivity measurements. Six different particle sizes were dissolved for each type of marble (from 0.1 up to 3.15 mm). The results obtained indicated that dissolution rate increased with an increase in pH and a decrease in particle size. The kinetics of calcium in river and distilled water permitted to discover that the dissolution of calcium followed the second rate reaction model 1/ ([Ca]t - [Ca]s) = k2t + 1/[Ca]t + [Ca]O. The principal criteria for the choice of the best marble were the mineralogical and chemical composition of the material.

Keywords

• Aggressive water
• Remineralization
• Marble
• Calcite
• Dissolution
• Kinetics