No abstract

The article presents the results of the first known industrial trials for the processing of uranium-containing slag obtained during blast-furnace smelting of carbonaceous iron-uranium ore (Zhovtorichenske deposit, Ukraine). It is shown that the fractional precipitation of iron and aluminum impurities allows reducing the losses of uranium and increasing the degree of utilization of nitrate nitrogen and ammonia nitrogen, additionally producing the ammonium nitrate as fertilizer. The scheme for chemical concentrate processing ensured a significant increase in the degree of uranium deposition into the finished product – up to 60%. Nitric acid sludge processing technology made it possible to maintain the water balance and completely prevented the discharge of off-balance effluents into the river Dnipro.

No abstract

To reduce climate change and carbonization of the atmosphere, today it is proposed to switch to green energy and use hydrogen as an energy source. When hydrogen burns, water forms, and carbon oxides are not released. Methods for processing solid, liquid, and gaseous fuels, as well as water electrolysis, are proposed for hydrogen production. The electrolysis of water ensures the production of chemically pure hydrogen. Its disadvantage is significant energy consumption and, as a result, high cost. The condition for the economically beneficial use of hydrogen is to reduce its cost to $1/kg. The existing designs of reactors and technologies for producing hydrogen do not allow achieving such efficiency, which is limited by the thermodynamics of the process. To reduce energy consumption, this paper proposes designs of reactors in which the process of oxygen evolution is replaced by the process of dissolving anodes made from production waste - iron and aluminium scrap. As a result of the measures taken, it is possible to reduce the voltage on the electrolyzers from 1.8 V to 0.5-0.6 V. This makes the hydrogen production process economically viable.

We analyzed the possibilities of the use of the cluster model of water to assess its viscosity. The Nemethy-Scheraga model was used in our study. In a simplified version, this model implies the presence of water cluster that are linked by hydrogen bonds as well as individual molecules (monomolecules) interacting only by van der Waals forces. The paper gives an estimation of average cluster size. Based on the experimental temperature dependences of viscosity and density, the content of monomolecules in water was approximately determined. In the first case, the ratio of the viscosity of water to monomolecules was estimated from the inverse Arrhenius temperature dependence of viscosity by considering experimental activation energy ~18.6 kJ mol–1 (0÷300C) and energy of dispersion interactions ~7.4 kJ mol–1. Then, the volumetric content of monomolecules was estimated by using the inverse Betchelor's formula, which relates the viscosity of the suspension (clusters) and dispersion medium (monomolecules) to their ratio. On the other hand, a similar estimation was performed based on the density of water, clusters that were considered similar to ice floes, and the estimated density of monomolecules. Both estimates showed that the volumetric content of water not bound into clusters does not exceed 9%. It was concluded that the structure of water most likely corresponds to the clathrate model, according to which some of the H2O molecules move into the middle of ice-like clusters, and vacancies are stabilized by H3O+–OH– pairs.