Problems and Prospects of Production and Qualification of Phosphoric Acid

Abstract

The qualification of phosphoric acid is carried out depending on the use of phosphates of various deposits and the necessary quality of the final products. An acquisition of phosphoric acid of the required quality should be carried out taking into account three aspects: resource-energy, ecology and complex processing. Solving the problems of one aspect entails solving the problems of the other aspects. The rational use of natural resources and the reduction of environmental pollution is the determining factor in the choice of technological regimes for complex processing of raw materials with a reduction in the volume of waste of all kinds or transferring them into forms easily recyclable or specially stored. The absence of economically sound technologies for processing phosphogypsum determines its preferential warehousing. The second component that requires recycling is fluorine. In this regard, the purification of phosphoric acid from fluorine should use technologies that realize the trapping of fluorine compounds released into the gas phase. This is relevant from the point of view of the complexity of processing raw materials with the extraction of rare-earth elements. The use of mechanochemical activation makes it possible to achieve a nanoscale level. To a lesser extent, this aspect relates to the stage of sulfuric acid decomposition, proceeding with the participation of three phases: solid, liquid and gas. In turn, the surface structure of the gas-liquid layer plays the role of an energy barrier for evaporation. To establish the basic energy patterns of concentration and defluorination n the disc apparatus and to optimize the process, a thermophysical model was developed in which the range of effective parameters was determined by the joint solution of a number of equations for the desired ingredients in the phosphoric acid concentration range of 52-65%. The solution of the problem of complex purification of wet-process phosphoric acid can be carried out by adsorption methods that allow to remove to some extent almost all impurities.For citation:Smirnov N.N., Smirnova D.N., Ilyin A.P., Kochetkov S.P. Problems and prospects of production and qualification of phosphoric acid. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 7. P. 48-56.