Background: Kyzylkum phosphorite combine wastes in form of off-balanced ore (13-15% Р 2 О 5 ) and phosphorite sludge (10-12% Р 2 О 5 ) generated during the benefication of high calcareous Central Kyzylkum phosphorite in recent years. Total volume of produced phosphorite has already reached 13 billion tonnes. One of actual and rational way for processing low-grade phosphorites is their usage during the preparation of composts based on chicken manure. Mechanism of activation is phosphorus transfer from low-grade phosphorite into acceptable plant form during composition with chicken manure and transformation of manure organic matter into humic substance consider as nitrogen and organic matter losses in atmosphere. Purpose: Research on the effect of organic-mineral fertilizer obtained from chicken manure and mineralized mass from Central Kyzylkum phosphorite by composting. Methodology: Compost was made by mixing chicken manure with mineralized mass of Central Kyzylkum phosphorite in wide range of weight ratio. The composition of resulting composts by world famous methods depending on time process has been studied.

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.

No abstract

No abstract

The process of obtaining fertilising precipitate based on the interaction of off-balance ore phosphorites of Central Kyzylkum and chemically enriched phosphorite concentrate with hydrochloric acid, followed by precipitation of hydrochloric acid extraction with suspension of calcium hydroxide. The optimal parameters of the precipitation were determined for the first time in our country. Influence of calcium hydroxide norms on degree precipitation hydrochloricphosphoric acid extracts are studied. The resulting samples of precipitates under optimal conditions contain in their composition 23.63-24.19% P 2 O 5(t.) , 21.09-21.38% P 2 O 5accep. by 2% citric acid to those 26.97-28.41% CaO (t.) , 23.52-25.59% of CaO accep. by 2% citric acid. The degree of precipitation equal 94.01-98.05%. Physical and chemical studies (x-ray phase analysis) of the mineralised mass and products of its processing were also carried out.