Phosphate Raw Materials Research Articles

Comparative evaluation of methods for determination of the rare earth elements content in phosphate raw materials

The increase in the rate of extraction and use of rare earth elements (REE) necessitates the study of their environmental and industrial safety. Despite the relatively low content of REEs in phosphate ores (less than 1.5% (wt.)), significant volumes of production of phosphoric acid and mineral fertilizers based on it require environmental monitoring of REEs both in the soil located in the immediate vicinity of phosphogypsum dumps and in the phosphate fertilizers themselves, which are the main source of REEs in it, paying special attention to the irreplaceable soils of greenhouse farms. Inductively coupled plasma mass spectrometry (ICP – MS) occupies the leading position today among the variety of direct methods for the quantitative determination of REEs. However, for a number of domestic producers of phosphate fertilizers, the ICP – MS method is still too complicated and expensive. As an affordable alternative, we can mention the spectrophotometric method (SPM), based on the formation of a colored complex of rare-earth elements with the analytical reagent Arsenazo III. On the example of a sample of phosphorite from the Polpinsky deposit, a comparative assessment of the possibility of quantitative determination of REEs in phosphate raw materials by the ICP – MS method is presented as the most promising, as well as the SPM as the most accessible. It is shown that the sensitivity of the spectrophotometric method is sufficient for the reliable determination of the amount of REEs in the phosphate raw material. The reasons for significant errors in determination of the amount of REEs in phosphate raw materials by the photometric method and possible ways to reduce them to values comparable with the error of the method are considered.

Review of methods and technologies for the enrichment of low-grade phosphorites

Abstract The article presents the results of generalization of known information on various methods of enrichment of low-grade phosphate raw materials in the world. Based on the review of literature materials, scientists propose several methods of enrichment: mechanical, calcination at high temperatures, flotation, chemical enrichment with various acids and salts. Analyzing and summarizing these data, the article describes the advantages and disadvantages of each proposed method of enrichment of low-grade phosphorites. It is known that the sphere of production of phosphorus-containing products is important for many agricultural countries that produce these products themselves or import from others. This review material is very important for those who are interested in the problems of attracting low-grade phosphates into the production cycle by enriching them.

RESEARCH OF THE PROCESS OF SYNTHESIS OF DIAMMONIUM PHOSPHATE FROM EXTRACTIVE PHOSPHORIC ACID FROM BALANCED PHOSPHATESILICON SHAPES OF THE KARATAU BASIN

The article describes the process of obtaining extraction of phosphoric acid from phosphate-siliceous phosphorite shales of the Zhanatas deposit, by the sulfuric acid extraction method of obtaining EPA for use in the production of diammonium phosphate. Extraction decomposition of phosphorite by sulfuric acid proceeds with the formation of phosphogypsum and with fluorine released into the gas phase in the form of HF and SiF4 and processed into H2SiF6. The studies were carried out using circulating solutions of EPA with a concentration of 3.80-18.91% P2O5, phosphorite with a content of, (wt. %) P2O5 - 18.14; MgO - 13.43; Al2O3 -1.01; CaO - 25.1; F - 0.58; CO2 - 19.55, etc., sulfuric acid concentration of 92.5% was diluted to 50%. The norm of sulfuric acid is 100% of stoichiometry for CaO and MgO. The impurities Fe2O3 and Al2O3 present in phosphorite by 82-91% are extracted into the phosphogypsum precipitate in the form of medium phosphates. Fluorine introduced with phosphate raw materials into the extraction stage passes into the production acid by 60-70%, 10-20% – into phosphogypsum, and in a small amount 8-12% is released into the gas phase. The resulting EPA product can be used in the production of diammonium phosphate

АНАЛИЗ ТЕМПЕРАТУРНО-КОНЦЕНТРАЦИОННОЙ ЗАВИСИМОСТИ ТЕРМИЧЕСКИХ ДЕФОРМАЦИЙ ФОСФОРИТОВ ПРИ НАГРЕВЕ

The work presents the results of experimental studies of thermal deformations of phosphate raw materials, which have a significant impact on the progress of chemical and energy technological processes of thermal treatment in roasting conveyor and agglomeration machines. Influence on the value of thermal deformations of chemical and mineralogical composition of phosphate raw materials supplied for processing was revealed. Parameters of thermal deformation during heating are determined taking into account heating rate. It has been found that thermal deformations in the region of high temperatures contribute to softening and melting of phosphate materials, thereby contributing to negative gas dynamics processes in the dense layer of phosphorite pellets on the sintering machine conveyor or in the sintering layer on the agglomeration machine belt

Recovery of used acetic acid via sulfuric acid

Kazakhstan has a huge phosphate raw material base, where the basis is made up of micro-grained phosphate ores of the Karatau basin. The depletion of reserves of high-quality commercial ores leads to the search for new methods of using the enrichment and sorting of low-grade technogenic ores, one of which is phosphate-siliceous slates. The presented study was carried out in two stages: at the first stage, phosphate-siliceous shales were enriched by the acetic acid method, regime technological parameters, kinetic and thermodynamic regularities of the process were determined. At the second stage of the research a method for recycling used acetic acid during the enrichment of low-grade phosphate-siliceous slates is proposed. In this case, sulfuric acid was chosen as the regenerating agent of acetic acid. The reliability of the performed studies was proved by the use of modern complex research methods: scanning electron microscopy, Energy Dispersive X-Ray and X-Ray difraction analyses. To determine the course of a particular reaction, a thermodynamic analysis was performed using modern HSC 6.0 software. The kinetic data are determined by calculation. The obtained experimental data were subjected to statistical analysis (Chaddock scale, standard deviation, coefficient of determination). The mechanism of interaction of an acetate solution with sulfuric acid is illustratively described. In conclusion, the sulfuric acid method is suitable for the regeneration of applied acetic acid. In this case, a by-product is formed in the form of calcium sulfate. This product can be used as a building binder (confirmed by the protocol of the “National Center of Expertise” of the Republic of Kazakhstan).

Design and operation of SOMEX column flotation machines for processing the Khibiny apatite–nepheline ore

The article discusses design variables and operation, as well as control and adjustment of process flows in column flotation machines of the same size from four different manufacturers. The relevance and key features of the column flotation method are shown. The main directions of modernization of column flotation machines with justification and comparison of operational characteristics are revealed. The technological performance indicators of the Russian flotation column, developed on the basis of a comparative analysis, are given. In Russia, column flotation machines are widely used in the flotation of phosphate raw materials. They are used at the processing plants of Apatit and North-Western Phosphorus Company, processing apatite–nepheline ores of the Khibiny deposits, and ensured a reduction in the number of refining operations from three to one. Column flotation machines of four manufacturers are used at these enterprises: CPT (Canada), BGRIMM (China), Metso Minerals (Finland), SPA SOMEX (Russia). Brief results of technological tests comparing the performance of two parallel sections, one performed on equipment manufactured by Metso Minerals, the second on the equipment of SPA SOMEX, are presented. It is established that the column flotation machine manufactured by SPA SOMEX takes into account the experience of operating columns from various manufacturers and is the most advanced version of column apparatuses.

MECHANICAL PROPERTIES OF PHOSPHOGYPSUM AND TRENDS ITS UTILIZATION

Phosphogypsum is a waste obtained by binding calcium in the process of sulfuric acid decomposition of phosphate raw materials in the production of phosphorus fertilizers. The article presents the results of complex laboratory studies of more than 500 samples of calcium sulfate hemihydrate and dihydrate. Calcium sulfate dihydrate (CaSO4·2H2O) is a solid fine-crystalline substance of white or gray color with the inclusion of large aggregates. Deformability, strength properties and permeability of calcium sulfate dihydrate were determined on specially prepared samples with a relative compaction of 0.95; 0.90 and 0.80 by the methods used in engineering and geological surveys. The internal friction angle, cohesion and coefficient of permeability have values typical for silty sands and sandy loam, and the compressibility characteristics are significantly lower due to the solubility of matter. This material is characterized by subsidence and suffusion sediment characteristic of carbonate rocks (dolomite, limestone). Calcium sulfate hemihydrate (CaSO4·0.5H2O) - a loose earthy mass of white or gray color, as the process of hydration and the appearance of cementation bonds turns into a semi-rocky technogenic soil of low strength. The characteristics of calcium sulfate hemihydrate were determined on the undisturbed samples taken from the dump after 1 and 6 months, 1, 5 and 10 years after storage. These characteristics are comparable to construction gypsum materials from lower grades. It is recommended to use calcium sulfate dihydrate as ground material when carrying out water-protective measures and neutralizing the acids contained in it, the use of calcium sulfate hemihydrate is significantly limited by its setting time.

Synthesis of NPK fertilizer from low-grade phosphate raw material

Abstract 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.

Simple superphosphate by two-stage acid treatment of phosphate raw materials

The distinguishing feature of the proposed flow method before the classical (chamber) method is that the entire production cycle of natural phosphate processing is carried out in two stages. At the first stage, the phosphorite is treated with a stoichiometric flow rate of concentrated sulphuric acid (at least 93%), under conditions of complete decomposition of phosphorite to form phosphoric acid and crystals of anhydrite (calcium sulfate). The reaction temperature is 122 °C. In the second stage, the resulting concentrated solution of phosphoric acid in a mixture with sulphur is involved in a reaction with an additional input of phosphorite, which is the basis for the mechanism of chemical formation of monocalciumphosphate and granulation of superphosphate mass. The processes for neutralizing phosphoric acid on monocalciumphosphate and for granulating the product by coagulation are combined in one apparatus. The drying stage of the product is excluded from the scheme.

OBTAINING HUMATE-CONTAINING NEW COMPOSITE PRODUCTS

The influence of various factors on the process of interaction in the systems "sodium humate-mixture of phosphoric and nitric acids" and "phosphorite-mixture of acids-sodium humate" has been investigated. The influence of the ratios of the initial components, the amount of sodium humate introduced, the rate of the acid reagent, the temperature and duration of the reaction on the interaction process in the systems under study was studied, and the optimal process conditions were determined. The methods of chemical and physicochemical analysis revealed that as a result of interaction in the studied heterogeneous systems, ammonium humate, sodium acid phosphates, as well as sodium and ammonium nitrates are formed. Based on the studies carried out, it was found that the introduction of sodium humate prevents the inhibition of the decomposition of phosphate raw materials and the retrogradation of P2O5, i.e. the sparingly soluble calcium hydrogen phosphate formed as a result of the interaction of the initial components under the influence of sodium humate transforms into a readily soluble dihydrogen phosphate. A basic technological scheme for obtaining new types of humate-containing composite products has been developed. A basic technological scheme for obtaining new types of humate-containing products has been developed, which allows obtaining two types of products: fertilizers and compositions. When sodium humate interacts with an acidic reagent, the finished product is a humate composition, and if phosphorite is added to the system, a humate-phosphate fertilizer. The resulting products have a high content of P2O5, nitrogen and humic substances.

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.

Accounting for strontium content in the system ameliorant - soil - plant to establish an environmentally safe dose of phosphogypsum

The strontium content in phosphogypsum, soil and plants has been studied. It has been established that during the processing of phosphate raw materials, most of the strontium passes into phosphogypsum, reaching 1.4-2.3% in it. With the introduction of a single dose of phosphogypsum (23 t / ha), the content of total strontium in the soil increased to 309-364, and a double dose to 402, which is below the maximum permissible level (600 mg / kg). The ratio between calcium and strontium in the medium sodium reclaimed chernozem solonetz was at a good and satisfactory level, and in plants it was more than 100, which is typical for territories with a relatively satisfactory ecological situation. Meliorative (calculated) agronomic and ecologically safe rates of phosphogypsum consumption for soils of solonetzic complexes of the Volga economic region are given.

Optimal Parameters for Obtaining Diammonium Phosphate from off-balance Phosphate Raw Materials of the Karatau Basin

The article contains information about substandard material resources of phosphorite raw materials of the Republic of Kazakhstan. Samples of phosphate-siliceous raw materials of the Zhanatas Deposit were studied for the content of P2O5. To obtain diammonium phosphate (DAP), off-balance phosphorite from the Zhanatas Deposit was used, containing P2O5-16.18%. Technological solutions for the enrichment of substandard phosphate raw materials `Zhanatas` and the production of DAP from evaporated and non-evaporated WPA are proposed. Information on mineral petrographic analysis and the chemistry of the DAP production process based on the results of X-Ray Diffraction, X-Ray Phase Analysis, and SEM is provided.

Acid-Thermal processing of phosphate raw materials

The article describes the methods of phosphate-thermal decomposition of phosphate rock S.K. The conversion of phosphorus as a result of heat treatment under conditions of reduced conditions of a reduced rate of phosphoric acid is given.Condensed phosphates are highly concentrated fertilizers and have advantages over conventional low percent fertilizers in terms of savings in transport, storage and use. They are less susceptible to degradation in the soil, are distinguished by a long aftereffect and a higher coefficient of phosphorus utilization by plants.

Перспективы использования глауконитсодержащих хвостов обогащения фосфоритов для снижения подвижности никеля в почвах

The phosphorite enrichment tailings (ET) of the Vyatka-Kama deposit are a valuable agrochemi¬cal raw material con-taining phosphorus, potas¬sium, sulfur and a complex of deficient micro¬elements. The presence of an effective natural sorbent glauconite (up to 70 %), lime and phos¬phate materials in ET plant makes it possible to use them as ameliorants for the rehabilitation of soils contaminated with heavy metals, in partic¬ular nickel. As a result of laboratory studies, it was found that the introduction of natural and ground ET, as well as fertilizers based on them in a dosage of 0.25 g per kg of soil leads to a decrease in the mobility of nickel in average by 35 %. The de-crease in the mobility of Ni may be due to the adsorption of this element on glauconite. The possibility of the formation of poorly soluble nickel phosphates cannot be ruled out either. The introduction of ET leads not only to a de¬crease in the mobility of Ni, but also to the en¬richment of the soil with phosphorus, potas¬sium, sulfur, and nitrogen. The accumulation of bound forms of nitrogen in the soil is due to the acti-vation of microbiological processes of nitro¬gen fixation. The agrochemically valuable composition is an important advantage of ET in comparison with lime materials used for binding Ni. Enrichment tailings are distinguished by environmental safety, low cost and availability. The use of ET as natural soil ameliorants will allow us to develop the tech¬nology of complex processing of extracted phos¬phate raw ma-terials and significantly reduce the amount of waste generated during the extraction and enrichment of phosphate raw materials.

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.

Institute of Geological Sciences, NAS of Ukraine

The aim of the research is to substantiate the expediency of themineral and radiogeochemical composition comprehensive study of phosphate raw materials from domestic deposits in connection with their promising use in agro-industrial production. Phosphates from five levels of phosphate accumulation (Vendian (Ediacaran), Visean, Alb-Cenomanian, Santon-Campanian and Eocene) from Ukraine territory were studied, as well as for the purpose of comparison –phosphorites from deposits in Syria, Belarus, Russia and Kazakhstan. Optical polarization, scanning electrone microscopy with energy dispersive analysis, X-ray diffractometric analysis and the method of semiconductor gamma spectrometry were used. Study results of phosphate mineral raw materials processing by different methods, including with the involvement of biotechnological methods (using the environmentally friendly leaching agents of microbial origin) are represented. The results obtained are the basis for determining the quality criteria of phosphate raw materials and assessing the prospects for industrial production of phosphorites from domestic deposits of various types. In turn, the improvement of phosphorite processing technology, as well as the involvement of modern biotechnological methods in the production will significantly reduce the cost of mineral fertilizers and related products, which is of economic interest in various sectors of the national economy.

Properties of phosphogypsum as technogenic soil

Phosphogypsum (CaSO4·2H2O) is heavy tonnage waste generated by binding calcium in the process of sulfuric acid decomposition of phosphate raw materials when obtaining wet-process phosphoric acid in the production of phosphate fertilizers. In appearance, it is solid fine-crystalline substance of white or gray color with inclusions of large aggregates. The paper presents the results of laboratory studies of more than 390 samples of phosphogypsum neutralized with construction lime. The deformation and strength properties as well as the water permeability were determined on specially prepared samples with the relative compaction of 0.95, 0.90 and 0.80 by methods used in engineering and geological surveys. While the angle of internal friction, the cohesion and the coefficient of permeability of the phosphogypsum have the values typical for fine or silty sands, the compressibility characteristics are significantly worse due to the solubility of the particles. Phosphogypsum is characterized by subsidence and suffusion settling, which are proper for carbonate rocks (dolomite, limestone). The use of the phosphogypsum as ground is possible for subbase of roads with low traffic intensity with a gravel pavement, for dams at industrial solid waste storage facilities, as well as for engineering reclamation of those storage facilities, but only if implementing water protection measures.

Reviewof methods for enrichment of phosphate raw materials in the world

Reviewof methods for enrichment of phosphate raw materials in the world

PRODUCTION OF AZOSUPERPHOSPHATE IN THE PARTICIPATION OF CENTRAL KYZYLKUM PHOSPHARITES AND AMMONIUM SULPHATE

This article sets out the results of the activation of low-grade phosphorite ore with concentrated solutions of ammonium sulfate. It was shown that treatment of the mineralized mass with a solution of ammonium sulfate leads to a sharp increase in the content of the assimilable form of P2O5 in phosphate raw materials. Granules of activated nitrogen-phosphorus fertilizers have sufficient strength, which meets the requirements of agriculture.