Flow of simple superphosphate using two-stage decomposition of phosphorite

The methods for producing simple superphosphate by two-stage sulfuric acid decomposition of natural phosphates are analyzed. For the first stage, the process of decomposition of high-carbonate powdered phosphorite is studied depending on the rate of sulfuric acid from stoichiometry to the formation of H3PO4, its concentration and the reaction time of the starting components. For the second stage, the process of neutralization of phosphoric acid is studied, depending on the norm of phosphate rock for the formation of Ca(H2PO4)2. The drying process of superphosphate is carried out, in which granular superphosphate is obtained, and P2O5total. - 12%, P2O5free. - 4.6%, P2O5dig : P2O5total = 90%, P2O5 water : P2O5total = 79%.

CALCULATION OF THE VALUES OF THERMODYNAMIC FUNCTIONS OF THE SULFURIC ACID DECOMPOSITION OF THE PHOSPHORITE CONCENTRATE OF THE RIVAT DEPOSIT OF TAJIKISTAN

В статье обобщены полученные результаты лабораторных исследований и расчета значений термодинамических функций процесса сернокислотного разложения фосфоритного концентрата месторождения Риват. Установлен минералогический состав концентрата рентгенофазовым анализом. Показано, что основной составной частью концентрата является карбонат-фторапатит. В ходе исследования показано, что повышение температуры неблагополучно влияет на сернокислотное разложение концентрата и оно протекает самопроизвольно при комнатной температуре. The article summarizes the results of laboratory studies and calculation of the values of thermodynamic functions of the process of sulfuric acid decomposition of phosphorite concentrate from the Rivat deposit. The mineralogical composition of the concentrate was determined by X-ray phase analysis. It is shown that the main constituent of the concentrate is carbonate - fluorapatite. In the course of the study, it was shown that an increase in temperature adversely affects the sulfuric acid decomposition of the concentrate and it proceeds spontaneously at room temperature.

Physico-chemical features of acid decomposition of dolomite

The results of studies of the physico-chemical regularities of the acid decomposition of magnesium-containing raw materials are presented and the optimal technological mode of the individual stages of obtaining magnesium sulfate is determined. It has been established that the process of obtaining magnesium sulfate based on dolomite includes the following stages: decomposition of magnesium-containing raw materials with sulfuric acid; filtration of the resulting suspension with separation of calcium sulfate and insoluble residue and subsequent washing; crystallization and separation of magnesium sulfate; drying the target product. The main technological parameters that determine the stage of sulfuric acid decomposition are: the rate of sulfuric acid, the duration of decomposition, the method and procedure for introducing reagents, the content of magnesium sulfate in the liquid phase of the suspension. In this case, the concentration of sulfuric acid cannot be considered as the main technological parameter, since its numerical value is selected depending on the value of the final content of magnesium sulfate in the liquid phase, which in turn is determined by its solubility in water. It has been proven that the use of a flocculant at the decomposition stage provides an increased filtration rate, improved filtration performance, as well as keeping the filter cloth uncontaminated. The results of chemical and X-ray phase analyzes confirmed that magnesium sulfate obtained from domestic dolomite raw materials in its composition corresponds to magnesium sulfate obtained from foreign types of magnesium-containing raw materials - magnesite, brucite - and fully complies with the requirements of TU 2141016-32496445-00 “Magnesium sulfate”.

Structural Design Simulation of Bayonet Heat Exchanger for Sulfuric Acid Decomposition

The heat generated in a high-temperature gas-cooled reactor can be used to drive the iodine-sulfur cycle to produce hydrogen. However, the sulfuric acid decomposition step requires a sophisticated sulfuric acid decomposer to increase the decomposition rate. The decomposition of sulfuric acid mainly occurs in the catalytic zone, and the optimization of its structure is very important for increasing the decomposition rate. This study focuses on the structural design of the catalytic zone of the sulfuric acid decomposer unit. The structure with double inner tubes is designed to analyze the influence of the inner tube heat transfer area and the catalytic volume of the annulus region on the decomposition rate. The species transport model is used to predict the proportion of products followed by analysis of the key factors affecting the decomposition rate of the catalytic domain. The results reveal that the new design attains the decomposition temperature requirements and increases the fluid velocity of the inner tube. This in turn promotes the heat transfer effect. The decomposition rate is negatively correlated with the flow rate. Nonetheless, a structure with double inner tubes which have the same total area of inner tube as a structure with a single inner tube has a better optimization effect than a structure which has the same annulus catalytic volume as a structure with single inner tube. It increases the decomposition rate by up to 6.1% while a structure which has the same annulus catalytic volume as a structure with a single inner tube does the same by up to 1.7%. The decomposition rate can be maintained at a relatively high level when the inlet velocity of the current structural design is about 0.2 m/s. This study provides a reference for the engineering design of sulfuric acid decomposer based on the heat exchange area and catalytic volume.

Pt-core silica shell nanostructure: a robust catalyst for the highly corrosive sulfuric acid decomposition reaction in sulfur iodine cycle to produce hydrogen

The platinum core silica shell catalyst has facilitated stable sulfuric acid decomposition at high-temperature which was not possible over bare Pt nanoparticles due to sintering and agglomeration.