Synthesis of sodium ammonium hydrophosphate and sodium dihydrophosphate based on extraction phosphoric acid from Central Kyzylkum phosphorites

The aim of the research is the synthesis of sodium ammonium hydrogen phosphate and sodium dihydrogen phosphate based on purified extraction phosphoric acid. The acid was purified from accompanying impurities by precipitation methods using sodium carbonate and metasilicate, washed burnt phosphoconcentrate, barium carbonate, acid neutralization with gaseous ammonia. Pre-neutralization of the purified solution of monoammonium phosphate with sodium carbonate to the ratio Na2O:P2O5 = 0.44 and subsequent drying at a temperature of 50 °С allows to obtain sodium ammonium hydrogen phosphate tetrahydrate, and at 100 °С sodium dihydrogen phosphate monohydrate. The individuality and purity of the synthesized substances was established by the methods of X-ray diffraction, IR spectroscopy, thermogravimetry and scanning electron microscope.

RESEARCH OF THE PROCESS OF DEFORMATION OF EXTRACTIONAL PHOSPHORIC ACID FROM PHOSPHORITES OF CENTRAL KYZYLKUM

The purpose of this research was to determine the optimal technological parameters for the purification of extraction phosphoric acid based on phosphorites of Central Kyzylkum from fluorine by precipitation with sodium salts. The influence of the norm of sodium silicate and the total norm of sodium carbonate and sodium metasilicate salts on the chemical composition and degree of precipitation of sodium silicofluoride was research. It is shown that the optimal norm of sodium metasilicate is the stoichiometric norm for binding fluorine present in the extraction phosphoric acid to silicofluoride and the total norm of sodium salts is 120-140%, the temperature is 70°C. Separation of the liquid and solid phases by settling is preferably carried out at a temperature of 30°C and a process duration of 120 minutes.

Conditions of receiving a phosphite as withdrawal – a by-product of production of nitrogen-phosphorus fertilizers

Application of a phosphite for construction of highways is expedient for economic and ecological reasons. Most effective use of a semi-hydrate form of a phosphite for construction of local roads. One of limiting factors of wide use of a phosphite in road construction is lack of due regulatory base. By production of extraction phosphoric acid on the Balakovo branch JSC Apatit the method of vitriolic decomposition of phosphorus-containing raw materials by sulfuric acid a lot of phosphoric acid with the subsequent division of the received phosphoric acid (a liquid phase) and educated crystalline hydrate of sulfate of calcium in a floor – or a digidratny form (a firm phase) on a vacuum filtration is used. Digidratny and semi-hydrate process of vitriolic receiving phosphoric acid along with two-phasic processes are the most economically effective processes.

The impact of functional groups of the surface of carbon materials on the efficiency of purification of extraction phosphoric acid from fluorine compounds

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%.