Precipitated Silicon Dioxide from Phosphorus Waste
Development of Technology for Production of Precipitated Silicon Dioxide ("White Soot") from the Waste of Phosphorus Industry
Tech Area / Field
- CHE-IND/Industrial Chemistry and Chemical Process Engineering/Chemistry
8 Project completed
Senior Project Manager
Urezchenko V M
Institute for Metallurgy and Ore Concentration, Kazakstan, Almaty
- National Nuclear Center of the Republic of Kazakstan / Institute of Nuclear Physics, Kazakstan, Almaty\nZhambyl Branch Kazphosphate Ltd., Kazakstan, Taraz
- University of Guelph, Canada, ON, Guelph\nLaval University, Canada, QC, Quebec City
Project summaryThe aim of the Project is development of environmentally appropriate and waste free technology of phosphorus slag complex processing into precipitated silicon dioxide (“white soot”), carbonate filling materials for mechanical rubber industry, varnish and paint industry, into construction materials and sodium tripoliphosphate.
Background of the Project.
Phosphorus industry is rather developed branch of chemical industry both in NIS and Western countries. It is known that thermal-electric technology gives in 8-10 tons of slag per each ton of yellow phosphorus. This slag is accumulated in waste dumps and complicates the environmental situation at the site.
Formerly, great number of research works devoted to utilization of phosphorus slag had been done in NIS countries. The research works were mainly related to construction materials, for example active mineral additives (stuff) for Portland cement. Currently this is the most important way of slag utilization in Kazakhstan and Central Asia. A workshop for processing of liquid slag into road material was built in Kazakhstan. There are some active enterprises that produce mineral wool from phosphorus slag. A technology for glass-ceramics production from phosphorus slag was also developed. Phosphorus slag is a component of alkaline cement and concrete, belite clinker and refractory bricks, clinker free binding agent, white and color binding agents, aerated concrete, silicate concrete, autoclave materials, pumice and glass-ceramic materials.
However, despite the variety of methods for phosphorus slag utilization the issue of its complete and effective utilization is not solved completely. Processing of the slag into mineral filling materials (for example, into silicon dioxide (white soot)) is one of efficient and prospective ways for its utilization. So, the project is devoted to development of a technology for production of mineral filling materials and improvement of environmental situation at the site via processing of phosphorus industry waste.
White soot is precipitated silicon dioxide with high surface area and specific structure. It is used as reinforcing stuff for tire rubber, artificial leather and shoe materials. Traditional raw material for such stuff is, so called, silicate lump – product of agglomeration of silicon dioxide and sodium hydroxide. The silicate lump is rather precious material in short supply. So, more actual is to produce white soot, from cheap raw material using simple technology. Great deposits of granulated phosphorus slag consisting mainly of glassy calcium silicate (90-92%) could be a valuable source for white soot production.
The feature of the Project is a possibility to produce carbonate-silicate cake (filling material for varnish and paint industry) and sodium tripoliphosphate (component of detergents) together with the white soot.
The authors of the Project have great experience in processing of waste from phosphorus, copper and lead enterprises as well as waste from power plants into valuable components. Formerly our experts accomplished a research work on white soot production from zirconium industry silicate waste.
The following researches are planned in the framework of the Project:
– Investigation of phase composition and structure of the slag in order to determine the nature of recovery agent.
– Determination of optimum conditions for phosphorus slag recovery and extraction of the silica into the solution.
– Investigation of the possibility to clean of the silicate solution from admixtures and the rate of cleaning.
– Elaboration of express methods for determination of white soot specific surface area.
– Determination of the conditions for white soot precipitation with necessary specific surface area and structure.
– Investigation of the possibility to utilize intermediates of slag processing into white soot.
– Pilot testing of the technology for complex phosphorus slag processing.
Expected results include:
– Determined phase composition and structure of the slag .
– Determined the nature of recovery agent.
– Determined optimum conditions for slag recovery and extraction of silica into the solution.
– Determined optimum conditions for purification of sodium-silicate solution from impurities.
– Improved express methods for determination of “white soot” specific surface area.
– Elaborated waste-free technology for complex processing of phosphorus slag into white soot with required specific surface area and filling materials for varnish and pain industry, construction materials and sodium tripoliphosphate.
The Project meets the ISTC objectives:
– Over 50% of the personnel of the Project are scientists and engineers from the Institute of Nuclear Physics of the National Nuclear Center of Kazakhstan, formerly involved in weapons activity.
– Implementation of the Project will let to utilize Kazakhstan mineral resources more completely. Phosphorus industry waste will be used as new raw material for mineral filling material production.
– Implementation of the waste utilization technology will help to solve some environmental problems of the region.
The International Science and Technology Center (ISTC) is an intergovernmental organization connecting scientists from Kazakhstan, Armenia, Tajikistan, Kyrgyzstan, and Georgia with their peers and research organizations in the EU, Japan, Republic of Korea, Norway and the United States.
ISTC facilitates international science projects and assists the global scientific and business community to source and engage with CIS and Georgian institutes that develop or possess an excellence of scientific know-how.