We studied the processes of desulfurization of phosphoric acid obtained by wet process from washed and roasted concentrate and subsequent purification of acid from bivalent and trivalent metals and fluorine via partial ammonization (at pH of 2 to 4). Purified ammoniated slurry containing 16.96% P2O5, 8.06% N, 0.09% CaO, 0.58% MgO, 0.004% Fe2O3, 0.031% A12O3, 0.78% SO3 and 0.52% F was fabricated by the removal of precipitates at the stages of desulfurization and partial ammonization. The rheological properties of ammoniated slurry with 40% moisture were studied. When the temperature is increased from 40 to 800C, both the density and viscosity decrease from 1.395 to 1.365 g cm–3 and from 80.8 to 48.7 cP, respectively. Ammoniated suspension with pH of 5.5 and 8.5 was applied to prepare mono- and diammonium phosphates with the ratio P2O5:N of 52:14 and 48:18, respectively. The sludge obtained after desulfurization and ammonization processes can be used as a slow-release fertilizer.

In this article obtaining complex nitrogen-phosphate fertilizers based on activation of phosphorite powder with partially ammoniated mix of phosphoric and sulphuric acids have been studied. In order to reduce the foaming of the process, for the first time a partially ammoniated mix of acids was used. The optimal technological parameters for activation phosphorite powder with partially neutralized mixes of sulphuric and phosphoric acids are the followings: the mix of sulphuric and phosphoric acids with a ratio of SО3:Р2О5 = 1.2; рН of acids – 2.5; weight ratio of ammonium sulphate-phosphate slurry towards phosphorite powder is 100 : 20; temperature is 60°С; duration is 30 min.  The composition nitrogen-phosphate fertilizers obtained in optimal condition contains (wt., %): N – 11.55; Р2О5total -24.61; Р2О5acceptable by citric acid -21.66; Р2О5 acceptable by EDTA -20.24; Р2О5water-soluble  -13.02; CaOtotal -13.59; СаОacceptable by citric acid -11.43. In that condition, granulated products of nitrogen-phosphate can be produced with high strength. The advantage of offered promising technology concludes in reduction two times expenditure of the most expensive ammonia in comparison with ammonium sulphate production and an increase in gross domestic product.

Complex, nitrogen-phosphate fertilisers are applied before seeding, with seeding and extra nutrition, while single phosphoric ones are the most effective under autumn ploughing. In that case, enriched superphosphate, more concentrated than single superphosphate, was obtained using phosphoric acid gypsum slurry semiproduct produced by the interaction of thermo concentrate with sulphuric acid and recycled phosphoric acid in accordingly dihydrate operation (60-80°C). However, the mix of sulphuric and phosphoric acids was not used those are usually applied in conventional ways for enriched superphosphate production. Phosphate raw material (PRM) is dosed into phosphoric acid gypsum slurry (PAGS) upon weight ratio of PAGS: PRM equal from 100: 15 to 100: 40 that provides a condition for slurry fluidity. Interaction of the components was Original Research Article

Development of a technology for obtaining enriched superphosphate and ammophosphate by processing washed and dried phosphorite concentrate (WDPC) in a single cycle. The optimal ratio P2O5WPPA:H2SO4mh :P2O5WDPC = 1:0.28:0.08 was found, at which the composition and properties of ammophosphate fertilizer are maximally improved and a single phosphorus fertilizer is additionally obtained. It has been established that on the basis of the solid part of the ammophosphate pulp, samples of enriched superphosphate are obtained with the following indicators (wt., %): Р2О5t. - 30.16-32.01; Р2О5ас.с.a. : Р2О5t. = 98.54-100; Р2О5water solubility (w.s.) : Р2О5t. = 54.3-55.5; N - 5.45-6.04. A sample of ammophosphate contains (wt., %): Р2О5t. - 52.43-53.31; Р2О5ас.с.a. : Р2О5t. = 94.81-96.27; Р2О5w.s. : Р2О5t. = 87.41-88.36; CaOt. - 4.01-4.26; N - 13.65-14.03 and SO3t. - 4.37-10.74. Ammophosphate consists of mono- and diammonium phosphate, ammonium sulfate and dicalcium phosphate. Superphosphate also contains activated phosphorite, complex salts and gypsum. The material balance of the process of their production in a single technological cycle has been calculated.

This article describes the results of the research conducted on the drying of different types of apricots. Experiments were conducted to study the chemical composition of apricots, the quality of the finished product after drying in three different ways, and the duration of drying. During the research period, the biochemical composition of fruits selected as raw materials was regularly analyzed. The highest indicator of the amount of dry matter in the composition was observed, and three-year average indicators were studied. Sugar is the main part of the dry matter content of apricots. Also, the content of sugar is an important indicator of the organoleptic properties of fresh and dried apricots. During the experiments, the sugar content of the selected apricot varieties was measured over the years, and average sugar content indicators were determined. Apricots are dried in three different ways - naturally, in special drying equipment with solar batteries, and artificially in laboratory conditions in the dryer data based on drying experiments are presented.