Authors: Mingkai Zhou Caiping Wang Yan Chen Xiao Chen
Publish Date: 2015/07/30
Volume: 30, Issue: 4, Pages: 781-786
Abstract
The relationship between Pb leaching concentration and the solution’s pH with time was analyzed when cement in its solidified form was leached in an acid medium The effects of the particle size of the solidified form the cement adding method and the hydration degree on Pb solidification were also investigated The experimental results indicate that cement is quickly dissolved and hydrated in the acid medium forming a CSH gel or silicic acid sol with good adsorption When cementPb solidified form is leached in an acetate solution the hydrated product erodes with time so the Pb concentration increases slightly in the beginning Then some of the Pb ions are absorbed by the newly generated silicic acid sol CSH Others produce PbOH2 precipitation for secondary solidification leading to a gradual decrease in the Pb concentration in a leaching time of more than two hours Moreover the particle size of the solidified form has important effects on the Pb dissolution When the amount of added cement is low with a pH of less than 95 the solidification affects the sequence of the original cement powder the cement hydrated powder and the cementPb solidified form When the added amount of cement increases with a pH of more than 11 the effect of adding methods on solidification decreases and the solidified form is a little better than others
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