Sorption isotherms was obtained in the form sulfate complex of cerium on the anion exchanger D-403 at a temperature of 298 K and pH = 2÷4 in the presence of various concentrations of magnesium sulfate. Thermodynamic description of the sorption isotherm sulfate complexes of cerium by the method, which based on linearization of the equations of the law of mass action modifed for the reaction of ion exchange. The values of the apparent constants of ion exchange and differential Gibbs energy calculated for the ions of Ce(SO 4 ) - 2 .
The information about life time of famous chemist and metallurgist N.S.Kurnakov and the capsule review of his scientific achievementsis represented in this paper. The formation of chemical and metallurgical scientific school in Saint Petersburg Mining Institute is shown.
Experimental data on solvent extraction of lanthanum (III) and samarium (III) by solutions of naphthenic acid from nitrate medium was obtained. Dependences of distribution coefficient of pH, concentration of organic and aqueous phase was obtained. thermodynamic characteristics of extraction equilibrium was calculated.
Experimental data on solvent extraction of lanthanum (III) and samarium (III) by solutions of naphthenic acid from nitrate medium was obtained. Dependences of distribution coefficient of pH, concentration of organic and aqueous phase was obtained. thermodynamic characteristics of extraction equilibrium was calculated.
Technology of solvent extraction and separation of cerium lanthanides by solutions of naphthenic acid in o-dimethylbenzene was obtained. The sequence of extraction Eu > Sm > Ce > La from nitrate media was calculated.
The kinetics parameters of phenol oxidation by MnO2 on the surface of iron-manganese nodules at pH = 5,5±0,5 at temperature region from 293 till 353 K was described in this paper. The oxidation reaction runs by second order on phenol. At temperature region from 293 till 353 K the limited stage is chemical reaction. The activation energy of oxidation on the surface of iron-manganese nodules is equal 6,65 kJ/mol, and it is less than it’s one for oxidation on MnO2 surface (42,0 kJ/mol). The oxidation products are hydrohinon and less than 10 pier. % p-benzohinon.
Extraction of iron (III) from nitrate solutions by acid in 1,2-dymethilbenzine was investigated. Dependences of pH and distribution coefficient was obtained. Optimal iron (III) and REM separation conditions was acquired.
The data on the extraction of aluminum and manganese by solution of oleic acid in o-xylene. The possibility of extraction separation of aluminum, manganese and cerium group lanthanides by solvent extraction from nitrate media.
The ion flotation of cerium (3+) and samarium (3+) from nitrate solutions by use of sodium dodecyl sulphate as a collector with addition of sodium chloride has been stated. The ratio of distribution coefficients and separation coefficient as function of the pH-aqueous phase with different concentration of chloride-ions has been analyzed. The separation coefficient has rise from 1,3 till 4,75 when chloride has been added.
Experimental data on solvent extraction of cerium (III), yttrium (III), lanthanum (III) by solutions of oleinic acid in o-dimethylbenzene was obtained. The possibility of extraction sepa- ration of cerium(III), yttrium(III), lanthanum (III) from nitrate media was shown.
Data on the extraction of cerium(III) and yttrium(III) by naphthenic acid solution in o-xylene from chloride media were obtained. The experiment showed W-shaped dependence of the distribution coefficient of cerium(III) and yttrium(III) on the Cl content in the equilibrium aqueous phase. The minima of the dependence are explained by the formation of non-extractable complexes MeCl 2 +and MeOH 2 +, the maxima - by the increase in the degree of dissociation of naphthenic acid and the increase in the ionic strength of the solution.
The thermodynamic calculation of solubility and ionic equilibria in phosphoric acid solutions of cerium(III) allowed us to estimate the ionic composition of solutions, describe the mechanism of crystallization and dissolution processes СеРО 4 ·0.5H 2 O, determine the dependence of solubility on temperature and concentration of solutions.
The thermodynamic calculation of oxygen solubility and ionic standing in solutions of cerium(III) phosphate acids allowed us to estimate the ionic composition of solutions and describe the course of crystallization and dilution processes of SePO 4 -0.5H 2 O, as well as to determine the dependence of oxygen solubility on temperature and concentration of solutions.
Kinetic characteristics of the process of nickel cations sorption by ferromanganese nodules were determined: reaction rate constants at different temperatures, apparent activation energy of the process.
Kinetic characteristics of the process of iron(II) sorption by ferromanganese nodules have been found: reaction rate constants at different temperatures, apparent activation energy of the process. The limiting stage of the process, which is a redox reaction of the first order, was determined.
Experimental data on the solvate extraction of cerium(III) and yttrium(III) by solutions of oleic and naphthenic acids in o-dimethylbenzene were obtained. After mathematical analysis of the dependences of the distribution coefficient on pH and the composition of the organic and aqueous phases, the structure and composition of the solvate complexes were determined, as well as the values of Gibbs free energies and equilibrium constants of the reaction.
The technology of obtaining zirconium oxide, zirconium halide compounds (chlorides, fluorides) from eudialyte concentrate with subsequent production of zirconium powders, titanium-zirconium and aluminum-zirconium ligatures by metal-thermal method has been investigated. It is shown that different zirconium materials can be obtained by applying different reducing agents: sodium, magnesium or aluminum-magnesium alloys.
The history of the formation of the departments of the metallurgical faculty and chemical-metallurgical school of the Mining Institute is presented. A brief review of the main stages of development of metallurgical and chemical sciences is given. The main achievements in the field of metallurgy and chemistry, which served as a basis for the modern scientific schools of the metallurgical faculty, are shown.
The purpose of this research is to develop a new method of extraction and separation of rare earth metals, which will be effective in hydrometallurgical processes, i.e. in the processing of eudialyte concentrate. The task of the research is the experimental determination of distribution and separation coefficients in solvent extraction of rare earth metals from aqueous solutions with organic extractants, as well as the calculation of the extraction mechanism and thermodynamic constants on the basis of experimental data.
The development of the chemical and metallurgical school of the St. Petersburg Mining Institute from the establishment of the university to the present time is shown. The main achievements in the field of metallurgy and chemistry, which served as a basis for the development of modern scientific schools of the metallurgical faculty, are presented.
In this paper it is shown that if in the electrolytic process the charge carriers do not participate in the electrode reaction, the Faraday minimum is not fulfilled. In this case, the electrolytic process agrees with the second law of thermodynamics in the following formulation "The work of the flow of electricity in an electrochemical system is spent on chemical reaction, heat generation and entropy drop due to physical processes".
Extraction of cerium (3+) with tributyl phosphate was studied. The extraction constants were calculated from the dependences of the distribution coefficient on the concentration of salvent and extractant. According to their values, cerium salts are arranged in the series chloride < sulfate < nitrate corresponding to the Pearson reduction of the "hardness" of anions.
In order to calculate parameters of purification of soils from 90 Sr the exchange isotherm of Sr 2+ Ha cations of iron (III) between Cambrian clay and aqueous solution with pH = 3 was studied. Isotherms of joint cation adsorption in joint presence are described by the Langmuir equation. Using the values of the Langmuir constants, the Gibbs constant and energy of ion exchange equal to 15 and -6.7 kJ/mol, respectively, were calculated. These values coincide with those calculated from the individual adsorption isotherms of Sr 2+ and Fe (III) cations on clay. According to the obtained constants it is possible to deactivate soils from 90 Sr contamination by means of ion-exchange washing with solutions of iron (III) salts, which is confirmed by field studies in the 5th quarter of Vasilievsky Island. The performed technical-economic assessment of the decontamination of the 5th quarter shows that the washing cleaning will give an economic effect of about 150 million rubles compared to soil removal and burial.
Adsorption of strontium and iron from aqueous solutions on various minerals was studied. According to the sorption capacity, the studied minerals can be arranged in the following sequence: Cambrian clay ~ kaolinite > potassium feldspar > albite > oligoclase. This sequence correlates well with the specific surface of the studied minerals determined by thermal argon desorption and their exchange capacity determined by methylene blue adsorption. Coefficients of distribution of Sr 2+ and Fe 3+ between minerals and aqueous solutions and ionic exchange constants between Sr 2+ and Fe 3+ were determined. The value of the latter value was 23.6 for albite and 17.1 for oligoclase. Therefore, aqueous solutions of iron (III) may be recommended for cleaning soils from strontium contamination.
It is experimentally proved that adsorption of Fe(3+) and Sr(2+) cations on Cambrian clay is described by the Langmuir isotherm. The adsorption limit is 0.026 and 0.034 mol/kg, respectively, and the capacity of the clay is 73±5 mEq/kg. The landing sites of cations are 38.0 and 28.6 Å 2 , respectively, and the radii of hydrated cations are 348 and 302 pm. The latter value agrees with the Stokes radius of 309 pm. The Langmuir constants are 731 and 294, respectively, and the distribution coefficients between the solid and liquid phases at rn = 3.0+3.5 are 27±4 and 10±1.8. The ion exchange constant for the reaction ½ Sr 2+ (s) + 1/3 Fe 3+ (aq) ↔ ½ Sr 2+ (aq) + 1/3 Fe 3+ (s) is 0.95. Based on the data obtained, it is feasible to clean the pounds from strontium-90 contamination by washing with a Fe(3+) salt solution. Field tests in the 5th quarter of Vasilievsky Island of St. Petersburg confirmed the conclusion. The initial specific radioactivity of the pound reached up to 1.07 10 -4 Ci/kg. At heap leaching the purification degree of 60% was obtained, in conditions of convective leaching 90%. A formula for calculating the conditions for obtaining a given degree of purification is proposed.
The content of rare-earth metals (REM) in Kola apatite is about 1%. In the production of concentrates over 8 million tons per year, more than 80 thousand tons of REM are dumped into waste dumps annually, polluting the environment. The main bulk of apatite is processed according to the sulfuric acid scheme to produce extractive phosphoric acids. To extract rare-earth metals from phosphoric acid streams with a capacity of 45 t/h, it is necessary to develop a process lasting several minutes, which does not affect the basic technology and does not require expensive costs of reagents. Crystallization of lanthanide combinations on inoculum directly from production solutions of extractive phosphoric acids meets the requirements. Another pressing problem is the purification of soils contaminated with heavy metals and radionuclides. In laboratory and natural conditions, the purification of soils from 90Sr contamination of the 5th quarter of Vasilievsky Island and Novozybkovsky district of the Bryansk region from 137Cs contamination has been studied. Among different methods of soil decontamination, the most cost-effective and suitable for large soil masses and large territories is soil washing with diluted solutions of mixtures of ammonium and iron (3+) salts. This method can also be used to clean soils from heavy metal contamination in mining regions.
