The basis of production of extraction phosphoric acid is two simultaneous processes: dissolving phosphate raw material in a mixture of sulfuric and phosphoric (formed in the process) acids and crystallization of calcium sulfate (phosphogypsum). Phosphogypsum is an inevitable large-tonnage and cumbersome waste at sulfuric acid processing of apatite, which is of interest not only as a source of building gypsum, but also as an alternative rare earth raw material does not have a natural activity and containing rare-earth elements as a cerium and yttrium groups. As a raw material for the production of rare earth elements, calcium sulfate of three types has been used: phosphogypsum from a sludge accumulator, calcium phosphate phospho-hemihydrate and calcium sulfate phosphate dihydrate from a carousel filter produced by extraction phosphoric acid at JSC "PhosAgro-Cherepovets". The extraction of rare-earth elements from phosphogypsum from a sludge accumulator by leaching (percolation) with inorganic acids with subsequent sorption on cation-exchange resins is considered. As an adsorbent for extracting REE from leach solutions, cationite "Purolite" S-150 is used. A static exchange capacitance of cation exchanger is found that is the capacity of the resin when equilibrium is reached with a solution of a certain volume and composition. The static capacity of cation exchanger for rare-earth elements is 1.57%, which indicates a good absorbing capacity. Desorption of rare-earth elements from the cation exchanger is carried out with a solution of ammonium nitrate. The optimal solution for leaching was found to be sulfuric acid with a concentration of 5% by weight. The degree of extraction of rare-earth elements from phosphogypsum with sulfuric acid is about 82%.Forcitation:Artamonov A.V., Smirnova D.N., Smirnov N.N., Ilyin A.P. Extraction of rare earth elements from solid waste of production of phosphoric acid followed by sorption on cation exchange resins. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 10. P. 87-93
The environmental problems of the production of extraction phosphoric acid and the effect of fluorine on the human body are discussed in the article. The creation of the industry of phosphoric fertilizers on the basis of processing of fluorine-containing phosphate raw materials and fluorine-containing compounds, the development of their application require the study of environmental consequences arising from this, because fluorine is characterized by high mobility in the biological cycle of metabolism. For the purification of phosphoric acid from fluorine was used carbon adsorbents such as active charcoal brand BAU, natural graphite deposits Kyshtymsky, P514 soot, charcoal. Experiments on the purification was carried out on non-evaporated half-hydrated extraction phosphoric acid which was produced by joint stock company «Apatit» in Cherepovets city in Russia. The following analyses were carried out: IR-Fourier spectrometry, research of acid–base properties of carbon materials by potentiometric titration, potentiometric method of fluorine determination in extraction phosphoric acid. It is mentioned that the carbon black P514 is the most efficient adsorbent for purification of extraction phosphoric acid. The total number of functional groups on its surface is 0.62 mmol/g, the degree of purification from fluorine compounds is 94.8%.
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