Thermodynamic study of oxide phase compositions at reducing iron ore coosit by coals of Karazhyra deposit

Application of coals as reducing agents in the direct iron reducing process is a perspective way. For solid-phase iron reducing from iron ore concentrate of Bapy deposit, Republic of Kazakhstan, application of coals of Karazhyra deposit was proposed. Chemical composition of iron ore concentrate of Bapy deposit is presented. By application of methods and means of thermodynamic simulation, analysis of oxide phase composition was carried out. As a result of thermodynamic studies, it was revealed that at reducing of concentrate of specified composition, iron and aluminum oxides, magnesium, calcium, barium, and alkaline metals silicates, sulfides and phosphor compounds are presented in the oxide phase. A dependence of oxide phase parameters on temperature and coal rate was established. It was shown that a number of aluminum oxide, titanium and barium compounds and calcium and magnesium silicates is not practically varying within the whole temperature interval. The number of compounds, containing phosphor, potassium, natrium is decreasing while temperature is increasing due to elements transferring in gas phase. The number of sulfides is decreasing with temperature increase till the whole disappearance in the condensed phase. The number of iron oxides at the temperature higher 872K depends only on reducing agent rate. The number of oxide phase at the temperature lower 853K is maximum, then begins to decrease while the temperature is increasing, the reducing processes are developing and at the temperature of 1013K after completion of reducing process it reaches its maximum value which is not changing then up to temperature 1773K. The studies carried out enable to evaluate slag properties at elaboration of resource-saving technologies of iron direct reducing and can be used at forecasting and evaluation of metallization processes and the further re-melting of materials obtained from Bapy deposit iron ore concentrate of and Karazhyra deposit coals.

Radiation Shielding Properties Prediction of Barite used as Small Aggregate in Mortar

Construction materials used in the nuclear industry used to be mainly heavy materials, including lead plates, radiation-resistant heavy concrete, etc. However, these materials are either toxic after a long time of use (lead) or difficult to construct (radiation-resistant heavy concrete) and their cost is rather high. Therefore, there is a need for the manufacturing of a new kind of material with good radiation resistance, which is light, easy to use, and costs less. Barium is less toxic and more cost-effective than lead. Due to the importance of barium compounds in radiation shielding, the study of gamma radiation interactions within these compounds becomes essential, so the most important part of such a study is the experimental one, which shows the effect of the barite powder in the radiation resistance of the mortar. The research results show that the higher the thickness and percentage of barite powder, the higher is the radiation resistance.

Technology of Producing of Sodium Hypochlorite from the Concentrate of Reverse Osmosis Systems

One of the modern methods of water demineralization and softening for domestic and drinking purposes as well as for its preparation in industrial production is a reverse osmosis. This demineralization method is peculiar for its concentrates that are formed due to reverse osmosis membranes and nanofiltration technologies, the utilization of which continues to be an unresolved problem. The article deals with the solution of such problem to utilize those concentrates, which are obtained using reverse osmosis and nanofiltration units. In this regard, it seems promising to reduce the volume of technological concentrate at the first stage by its repeated concentration according to nanofiltration - reverse osmosis scheme. After that, the nanofiltration concentrate containing predominantly divalent Са2+, Mg2+ and SO42- ions is subjected to reagent treatment in the following sequence: first stage with barium compounds and second stage with carbonate and sodium hydroxide. Such sequence allows separating from the solution at the first stage practically insoluble BaSO4 with its precipitation in the 1st stage vortex reactor and, further precipitation of slightly soluble in alkaline medium CaCO3 and Mg (OH)2 in the ІІ stage reactor. These insoluble BaSO4, CaCO3 and Mg (OH)2 salts thrown off the mass balance are finally dehydrated using a filter press and subjected to subsequent sale as a market product or raw material. The obtained solution of sodium chloride is concentrated by 3-stage reverse osmosis resulting in a 0.8-1.0% aqueous solution (8-10 g/l) of sodium chloride solution, a high-grade raw material for the production of electrolytic sodium hypochlorite with 4-6 g/l concentration by chlorine equivalent.

Study of Thermal Reduction of Barium Sulphate for Barium Sulphide Preparation

Industrial wastewaters, particularly those associated with mining and mineral processing, can contain high con-centrations of sulphate. There are various methods of sulphate removal e.g. reverse osmosis, ion exchange, precipitation by lime, cements, and salts of barium and the biological removal process. The soluble salts of barium are most commonly used for precipitation of sulphate from aquatic acidic solutions to the insoluble product barium sulphate BaSO4. Benefits of precip-itation are high sulphate removal efficiency but limitations are toxicity of barium compounds and high economical costs. For this reason the recycling of BaSO4 to barium sulphide BaS (the precipitating reagent) is very important. The paper deals with study of BaSO4 reduction by activated carbon to BaS by thermal analysis and infrared spectrometry. DCS analysis indicated that conversion of BaSO4 to BaS in the range of temperature 800–1,000 °C was performed. Thermal analysis and infrared spectra of the products confirmed the change in its composition, but process of reduction by carbon was incomplete and in sample was still present a part of BaSO4. Presence of BaS was confirmed by colorimetric method.