Synthesis of NPK fertilizer from low-grade phosphate raw material

The article presents the results of studies of the process of obtaining NPK fertilizer from low-grade phosphate raw materials with P2O5 of about 18%. Phosphate raw materials were leached with a mixture of nitric-phosphoric acids with the addition of potassium carbonate, which serves as a source of potassium in the final product. The main parameters determined were the content of the main nutrients P2O5:N:K2O, temperature and time of the leaching process. According to the graphical method, the “apparent” activation energy of the heterogeneous process is found, which is equal to 3.8 kJ/mol indicates the intradiffusion nature of the process. Methods of chemical analysis, scanning electron microscopy and XRD analysis were used for a comprehensive study of raw materials and final products.

Mathematical Model for the Kinetics of Heterogeneous Reaction of Carbonates Dissociation in the Process of Roasting in the Presence of Temperatures Gradients in Phosphate Raw Material

The paper deals with the investigation of the parameters for the structural and kinetic rate equation of the carbonates dissociation reaction, in accordance with the obtained results of the nonisothermic experiment, in the conditions of gradient temperature presence in the investigated samples. The most significant is the study of physicochemical transformations kinetic laws, which degree of completeness effects the quality of intermediate products directly, that is decarbonization and sintering. The main part of the process, when phosphorites are heated, takes place in a solid phase. The feature of topochemical reactions is their localization in the aria between a solid phase surface of the initial substance and the reaction products. This surface is formed and changed, as a result of chemical and power technological process for roasting, determining the dependence of the reaction rate on time. The method of thermal analytical experiments is used. The reverse kinetic problem is solved in the temperatures range of the chemical–technological process for roasting phosphate raw materials on conveyor indurating machines. The authors propose a method of approximate calculation for the parameters of kinetic equations which allows to reduce errors, caused by the heat exchange processes in a measuring cell, significantly. The obtained results and their accuracy are suitable for the practical application.

Actual situation and prospects for the development of the phosphate-raw material base of Russia

The article analyzes the state of the phosphate raw material base in Russia and its role in the economic development of the country and in domestic agriculture especially. The problems that prevent the creation of a modern powerful phosphate production capable of satisfying the existing demands of agriculture in phosphoric mineral fertilizers are highlighted. The possible directions of the development of the phosphorus industry in the regions for the near and distant prospects are analyzed. The aim of the article is to analyze the current state of the domestic mineral resource base to produce phosphorus fertilizers, the acute shortage of which hinders the development of the country's agriculture. Actual base for research was mainly processed materials from specialized scientific articles and publicly available publications. In addition, data collected by the authors during thirty years of studying phosphorite deposits in Russia and foreign countries were involved. The analysis of published materials of leading Russian producers of phosphorus products, mining companies, databases of specialized federal and regional geological companies. It is concluded that before the country's geological services, the most important task remains to identify deposits of high-quality phosphate ores, and especially in Siberia and the Russian Far East. Significant prospects for the development of these regions are opened by the Northern Sea Route. The planned pace of its development offers unique opportunities for the economic development of the Taimyr-Anabar region, where huge resources of apatite-bearing carbonatites of the Tomptor alkaline massif and Meimech-Kotuy province are concentrated.

The main ecological aspects of the complex processing of natural phosphate raw material

In the Russian Federation a unique phenomenon of nature as the reserves of phosphate raw materials and reserves of associated components are Apatite-nepheline ores of the Khibiny Deposit, located in the Central part of the Kola Peninsula. The main consumer of this raw material are the plants basic chemistry, processing of Apatite in a wet-process phosphoric acid sulfuric acid decomposition (the city of Cherepovets, Balakovo, the resurrection, etc.). This gives a dihydrate or hemihydrate wet-process phosphoric acid, and piecework output of dry phosphogypsum is 4 to 6 t per 1 t Apatite, depending on the ratio therein of CaO/P2O5 and the method of obtaining. The problem of disposing of chemical wastes are illustrated by various examples. Provides a conclusion on the feasibility of processing into fertilizer of phosphate raw materials, and scarce Apatite – to obtain construction materials. First developed a fundamentally new, environmentally friendly technology to produce phosphoric and complex fertilizers on the basis of wet mechanical activation of the phosphate. Methods have been pilot tested in the experimental shop at Moscow Production Association «Phosphate» (Voskresensk) using (0.3 t/h) and industry – to Estimate povorotniki (Aksai) (1.0 t/h) on the basis of vibrating mills. The implementation of methods obtained new types of fertilizers: granular and suspended mechanically activated phosphates and ammophosphate. It is concluded that from the point of view of environmental safety and economic feasibility of fertilizer phosphate should be recycled raw materials, and scarce Apatite should be directed to the production of construction materials oncooking phosphate with the simultaneous extraction and recovery of rare earth elements.

Nitrogen-Phosphorous Fertilizers on the Base of Concentrated Ammonium Nitrate Solution and Central Kyzylkum Phosphate Raw Material

This article presents obtaining of nitrogen-phosphate fertilizers by reacting ordinary phosphate powder from Central Kyzylkum (Uzbekistan) with 70-90% ammonium nitrate solution at 100ºС. Chemical composition of the fertilizers was determined fully. Relevant consistence of acceptable forms of Р2О5 and СаО in the product extremely decreased by the increase of amount of phosphate raw material (PRM) in reaction mixture. The addition of phosphate additive into ammonium nitrate solution significantly increases toughness of ammonium nitrate granules and their growth velocity proportionally by phosphate powder added. Herewith, initial concentration of ammonium nitrate did not effect practically on the granule’s toughness. It is described that, phosphate additive decreases the speed of solubility of ammonium nitrate granules almost up to 1.83 times. On our opinion, decrease of fertilizer solubility is the result of growing phosphorite share in the products. The more is the phosphorite share, the more slowly dissolution process of the fertilizer granule does occur.

Optimization of Decomposition Process of Karatau Phosphorites

Phosphorous-acid process of Karatau phosphorites’ decomposition has been studied. The impact of temperature, time and acid rate on decomposition process of phosphate raw material, the conditions ensuring maximum degree of phosphorite decomposition have been identified. Variance estimate of experiment results’ reproducibility has been carried out by mathematical statistics method; the coefficients of regression equations have been set. The significance of regression equation coefficients has been checked up by Student’s criterion, and the adequacy of regression equation to experiment has been checked up by Fisher's criterion. With the use of utopian point method the parameters of studied raw materials’ decomposition have been optimized.