Chemical Science International Journal

Background: Kyzylkum phosphorite combine wastes in form of off-balanced ore (13-15% Р₂О₅) and phosphorite sludge (10-12% Р₂О₅) 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.

Originality: There have been explored the rate and kinetics of transition of manure organic part in humic substances and transfer of Р₂О₅ into acceptable for plant form for the first time. It was established that decrease of organic matter and nitrogen emission into atmosphere during the composting manure by mineralized mass from Central Kyzylkum phosphorite. In addition, some chemical equations processing during the composting manure by phosphate were described.

Findings: Preparation of composts has been done based on manure and mineralized mass from Central Kyzylkum phosphorite when weight ratios of Dung: phosphorite (from 100:2 to 100: 25). In prepared mixing some water was added based on calculation to reach humidity till 70%. There have been determined the kinetics and rate of transformation of manure organic parts in humic substances and unacceptable form of phosphorus into acceptable form for plant in mineralized mass. The level releasing organic matter and nitrogen into gas phase has been determined during the composting manure with mineralized mass from Central Kyzylkum phosphorite. It was shown that with increasing duration of composting all ratios formation of humic substances and mobile phosphorus are grown while with increasing amount of mineralized mass in the compost organic matter and nitrogen losses are reduced, as well as the transformation rate of manure organic parts in humic substances. It has been found that when weight ratio of Dung: phosphorite = 100:2 during the composting losses of organic matter and nitrogen are 20.36% and 25.42 % respectively, as relative Р₂О_{5(acceptable)} by EDTA and 2 % solution of citric acid make up 69.44 % and 61.11%, while at 100 : 25 the losses of organic matter and nitrogen are 8.75 and 13.26 %, as relative Р₂О_{5(acceptable)} by EDTA and 2 % solution of citric acid constitute 43.81 and 42.38 %, respectively.

Humic acids of natural origin were oxidised with hydrogen peroxide and Fenton’s reagent to produce hybrid adsorbents based on mesoporous carbon. The characteristics of the modified humic acids and hybrid adsorbents were studied. Oxidation of humic acids provides an increase in adsorption of Cd (II), Cu (II), Pb (II) and Zn (II) by hybrid adsorbents. The values of adsorption capacity increase with increasing pH and vary in the order Cu> Pb> Zn> Cd.

In this study, the solvent extraction of chromium(III) and manganese(II) with N, N¹- ethylenebis(salicylimine) were carried out from different concentrations of various mineral acids (HCl, HNO₃, H₂SO₄, and HClO₄). In the range of analytical concentrations of the acids studied (0.0001-2M), it was discovered that the distribution ratio was highest in 0.0001M HCl and lowest in HClO₄ for chromium (III) and manganese (II). The stability constant of the extracted species suggest that chromium (III) specie is more   stable than manganese(II) specie (Logβ Cr(III) = 5.98 and Logβ Mn(II) = 5.88). Also, the extraction system suggests a chelating mechanism where mononuclear ion pair chromium(III) H₂EBSI complex and dinuclear ion pair manganese(II) H₂EBSI complex are formed.

One of the major environmental issues that have severe adverse effect on sustainable agriculture productivity is soil salinization. A research was conducted at Ho-Keta plain in the Volta Region of Ghana to assess the extent of degradation of salt-affected agricultural soils. Two soil series, Oyebi and Ada in three salt-affected areas within the Lower Volta basin in the Ho-Keta plain were selected from Anyako, Anyenui and Atiehife. Soil sampling was done randomly at the depth of 0-30 cm from the soil sites and transported to the laboratory for analysis and measurement of pH (4.61) Calcium (5.60meq/l), Magnesium (3.17meq/l), Sodium (6.95meq/l), Potassium (1.83meq/l) and Electrical Conductivity (5.13dS/m) respectively. The mean values of Ca, Mg, Na and K were used to estimate Sodium Adsorption Ratio (SAR) and Exchangeable Sodium Percentage (ESP) respectively. The mean values of SAR and ESP in the three selected areas were: 43.89, 52.02, 42.85 and 33.87%, 40.77% and 37.83 5% respectively. The results revealed land degradation in the study area as a result of high levels of SAR and ESP leading to low soil chemical properties. Further investigation to show the extent and the nature of soils in the study area is highly recommended.

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 performed at 70°С for 60 min. Then the superphosphate mass obtained was downloaded from reactor followed by ripening at 95-100°С, cooling, and obtaining final products. Since optimal weight ratio of PAGS: PRM is 100: 25 and 100:30 respectively depending upon the grades of PAGS in which samples of enriched superphosphate are obtained with high total and assimilated form of Р₂О₅ having of water-soluble that of Р₂О₅ no less 50%. It should be explained the requirement of agriculture on single phosphoric fertiliser possessing high content total and acceptable form of Р₂О₅ and water soluble that of Р₂О₅ no less 50% towards to total Р₂О_5.