Producing environment-conscious building materials from contaminated phosphogypsum

Title: Producing environment-conscious building materials from contaminated phosphogypsum
Author(s): K. Kovler
Paper category : conference
Book title: RILEM International Symposium on Environment-Conscious Materials and Systems for Sustainable Development
Editor(s): N. Kashino and Y. Ohama
Print-ISBN: 2-912143-55-1
e-ISBN: 2912143640
Publisher: RILEM Publications SARL
Publication year: 2004
Pages: 241 - 250
Total Pages: 10
Nb references: 8
Language: English

Abstract: It is known that dozens millions tones of contaminated phosphogypsum (by-product of fertilizers industry) in Morocco, Togo, USA, Canada, Russia, Korea, China, India, Israel, Jordan and other countries are disposed annually. The review of the suggested processes of purification shows that no effective technologies are known for phosphogypsum processing and utilization in construction industry. The central problem of phosphogypsum is slightly elevated radioactivity of the phosphogypsum (radium content is usually 16-22 pCi/g), because other chemical impurities can be extracted relatively easy, for example, by using phase transformations between different kinds of calcium sulfate hydrate and filtering the solution. Traditional technologies of purification of phosphogypsum from radium are not effective, because of the similarity of chemical properties of radium sulfate and calcium sulfate, when the contaminant salt is isomorphously introduced in the gypsum crystals.The authors suggest a principally new technological approach to purify phosphogypsum from radioactive and other contaminants, which make possible producing environment-conscious building binders. As preliminary laboratory tests showed, the radium content in phosphogypsum decreased from 20 to 0.4 pCi/g, and from gray contaminated phosphogypsum having 1.5% of P2O5 and 0.7% of sulfate/phosphate/silicofluoride salts of number of metals pure gypsum of white color containing the traces only of these impurities and of P2O5 was obtained. The economical, geographical and environmental aspects of processing phosphogypsum for environment-conscious construction are discussed.

Online publication: 2004-11-24
Publication type : full_text
Public price (Euros): 0.00
doi: 10.1617/2912143640.029