Utilisation of waste rafinate from extractive purification of crude phosphoric acid

Project co-ordinator: Prof. Dr. Viktor Grilc

In the proposed project, a systematic approach towards prevention/reduction of industrial pollution will be studied, taking into account some typical processes from Slovenian chemical or other industries (metallurgical, leather, paper....) . The main process under consideration will be extractive purification of crude phosphoric acid, which is currently being developed in a chemical company, aimed at production of feed and food grade phosphoric acid and its salts. In this process significant amounts of waste, depleted phosphoric acid (so called raffinate), containing all the impurities from the inlet raw acid: heavy metals, arsenic, fluorides and some organics (from the raw acid and the solvent). The project will be oriented towards making contributions to sustainable industrial development. Specific case problem(s) from chemical industry will be studied in order to develop a method avoiding generation of chemical waste and to increase the yield. Though it is difficult to expect the results to fit the zero waste concept, we believe considerable room exists for improvement of process efficiency and reduction of the environmental burden. The improvements will be sought by means of technical and organisational optimisation of the production process:

identification of the average quantities and composition of waste raffinate
definition of the main options for:
- waste prevention/minimisation at source
- waste recycling in the basic process
- waste recycling in an alternative process
- waste utilisation for other uses

feasibility analysis of the main options
experimental R&D work in the laboratory, design of pilot testing, product testing,
preparation of basic technical documentation (description – block diagram, mass and energy balances, environmental impact assessment, process flow sheet...) for an industrial plant.