Alternatives to Industrial Recycling of Phosphogypsum in Brazil

Residual gypsum from phosphoric acid plants has been a world-wide problem, concerning the environment, disposal and handling. In Brazil, till the end of 1989, the phosacid plants had accumulated 30.0 million tonnes of that by-product, corresponding to 5.5 million tonnes of recoverable sulphur, equivalent to US$ 625 million. This phosphogypsum storage increases at a rate of 3.4 million t/a which represents more than a half million t/a of sulphur. Since 1984, Petrofertil has been coordinating a systematic alternatives evaluation for industrial recycling of phosphogypsum, of which the most viable seems to be sulphur recovery in the liquid form or as sulphur dioxide. These alternatives are briefly examined under technological, economic and calcium co-product diversification and market aspects. The economic approach considers the investment per produced tonne, the value of co-product market and energy costs. The conclusion tries to define an objective strategic approach concerning to the problem of sulphur recovery from phosphogypsum.