Резкоземельные элементы и стронций в фосфогипсе
2009
Makhnach, A.A. | Gulis, L.F. | Tratsevskaya, I.R., Belarusian Research Geological Exploration Institute, Minsk (Belarus)
Phosphogypsum - a waste material of the phosphoric fertilizer production at the Gomel Chemical Plant (the Republic of Belarus) is on the average 94% gypsum. The mean content of a sum of rare-earth elements (REE) is 0,4-0,5%, of Sr -2,4%. The REE sum is 75% light lanthanides. Ce constitutes the major portion (40%). More than 80% of the total REE amount in phosphogypsum is confined to a complex water-insoluble material consisted of a technogenic mineral, which structure is similar to that of the strontium hydroxylapatite, as well as of X-ray amorphous silicate (hydroxide) material. This water-insoluble material comprises 1,5-2,0% of the total phosphogypsum and its average contents of elements are as follow: La – 7,5, Ce - 12, Pr – 0,5, Nd – 2,6, Y – 0,51, Sr – 14,2, Вa – 1,9, Ti – 3,1%. Such a concentrate rich in rare earths and strontium can be easily obtained in the laboratory experiment by dissolving phosphogypsum in water. However, this approach is not applicable for industrial purposes, because it needs a tremendous amount of water, a long-term dissolution and the recovery of enormous volumes of waste sulfate-calcium solution. The specific density of the material rich in REE and Si (3,28 g/cm3) is essentially higher than that of the gypsum host material (2,32 g/cm3). However, a very high dispersion of phosphogypsum and the REE- and Sr-bearing material, especially, this material sealing in a fine-crystalline gypsum matrix are factors which make difficult the development of gravitational and/or flotation technology for obtaining rare metal concentrate
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