No abstract

At the present stage of binding materials science development the possibility of low-clinker and non-clinker binding materials effective using with non-fired clay minerals is theoretically and practically proved. However existing views for clay raw materials role in such systems are mainly based on its role as a plasticizer of hardening systems which doesn't participate in basic phase-formation processes. Based on modern positions of nanochemistry, accumulated knowledge and own research results we present data on physical-chemical research of "clay-SiO 2 -CaO-H 2 O" system. The possibility to eliminate a specific property of clay inversion due to the directed combination of raw mix hardening conditions for phase-formation irreversible reaction provision is shown taking into account clay mineral aluminosilicate core participation forming a strong stone. It is shown that when South Kazakhstan clay materials using the low-temperature calcium hydro-and alumosilicates formation is possible in "clay-SiO 2 -CaO-H 2 O" system. Hereat sample compression strength can reach 5 MPa in already 15 days of natural hardening. The model system was studied at mixing of clay, sand, slaked lime and an alkaline additive of sodium carbonate. Components mixing and grinding was carried out in a ball mill. Reached high dispersion of products and also the factor of mechanicchemical activation ensured the beginning of phase-formation processes with participation of aluminosilicate core of a clay component. It is revealed that water function in such systems can be changed in time. One can assume that the rate of new phase appearance co-ordinates closely with water condition at disperse system transition into stone-like condition. It is realized only when sufficient degree of macroparticles closing is provided. In this case the interlayer water role can be double, i.e. positive or negative one, and this phenomenon predetermines possibilities of management with structural-rheological properties of similar systems in the area of high specific surfaces and concentrations. It was especially demonstrated at clay-composite formation under high pressure. Clay-composites of 60 MPa strength and with water resistance factor more than 0.9 are obtained at optimal water content and component dispersion ability. Samples with smaller surface activity (smaller fineness degree) with identical water content of a shaped mix displayed rheological properties at smaller pressing pressures. In this case loosely-coupled "film" water plays a role of a damping agent in the pressing moment in systems with contact-condensation hardening mechanism. It is like «capsulated» in intergrain space of formed structures and is in loosely-coupled condition. Such structures aren't water-resistant ones and their strength is lowered. Using various production methods one can provide conditions for this loosely-coupled water consumption exclusively for processes of hydroxylation and new nearborder aluminosilicate phase formation. In this case strong stone-like water-resistant...

В статье рассмотрены результаты исследования процесса переработки отмытой ка- лийной руды месторождения Челкар с целью получения безбалластного калийного удобрения. Изучена эффективность двух- и трехкратной отмывки руды от солей натрия для определения оптимально- го режима обогащения руды по калию. Установлено, что целесообразно проводить двукратную от- мывку руды промывной водой, при которой обеспечивается максимальное содержание в руде калия и минимальное содержание солей натрия. Эффективность отмывки подтверждается результатами рентгенографического анализа руды после второй отмывки. Прокалка руды приводит к дегидрата- ции кристаллогидратов минералов и возрастанию содержания в ее составе основных компонентов. Растворение прокаленной руды при температурах 50 и 90°С приводит лишь к частичному переходу в раствор солей калия и магния при полном растворении остаточного количества солей натрия. Для достижения полного растворения сульфатов калия и магния, являющихся целевыми компонентами для получения минерального удобрения, требуется изучить химические методы превращения.

With the huge explored reserves of potash salts in Kazakhstan, there is still no production of potash fertilizers, the demand for which is constantly growing. In this regard, research of processing of the largest Chelkar deposit ore into potash fertilizers and salts is an urgent problem. The article presents the research results of washed potash ore decomposition with nitric acid and nitric acid suspension filtration. The filtering properties and granulometric composition of the insoluble residue were studied, on what basis the decomposition mode with precipitate double washing was determined. To ensure good suspension filterability, washed, uncalcined ore should be used. Tests of a by-product, gypsum, as a gypsum binder were carried out, which confirmed its compliance with the normally hardening gypsum binder of the G-2 B grade. Advantage of the obtained gypsum is its environmental friendliness. Salts, which are chlorine-free water-soluble potassium-magnesium fertilizers have been obtained by crystallization from nitric acid solution. On the basis of results of experimental-and-laboratory tests, a basic flow scheme has been developed for obtaining potash and complex potassium-nitrogen-magnesium fertilizers from the Chelkar deposit ore.

Potassium-magnesium ores of the Chelkar deposit in Kazakhstan have a complex mineralogical composition and contain soluble sodium salts, which are an impurity component in the processing of ore into potassium fertilizers. In this regard, enrichment of natural potassium salt by incomplete dissolution was studied. Based on the experimental results the optimal washing mode was determined which ensures maximum removal of sodium salts from the natural salt composition and minimal losses of potassium salts with washing water. Mathematical models of the process under study were obtained through statistical processing of the experimental data. The results have shown that statistically, reliable regression equations are ones that describe potassium and sodium content in the solid phase relative to the process duration and water consumption for washing. The models can be used to operate the potassium ore enrichment process and to predict dependencies under various process conditions. 3D visual analysis of the process using regression surfaces for all significant equations has revealed the relationship between potassium ore enrichment indicators and process parameters.