Shows the shortcomings of traditional roasting-selenide technology of extraction of selenium. The results of studies on the development of reagentless electrochemical method of removing it. A basic technological scheme of obtaining technical selenium in terms of electroextraction was offer.
The results of the technical and mineralogical studies of washability of low quality bauxites of North Onega deposit are presented. The experiments of determination of the grindability of raw materials including without ball grinding and assessment washability bauxite by magnetic separation and flotation were conducted. These ores are very complex object for enrichment, as characterized by extremely thin impregnated aluminum-containing minerals, as well as the similarity of their properties. Further work of to conduct experiments using chemical enrichment (as soon as the chemical enrichment, and in combination with the physical methods of enrichment) is planned.
The theoretical basis of the synthesis of calcium hydrocarboaluminates 4CaO×Al2O3×mCO2×11H2O based on the CaCO3 in the aluminate-base system. We construct the isotherm of metastable equilibria in the system CaCO3 – 4CaO×Al2O3×mCO2×11H2O – 3CaO×Al2O3×6H2O – NaAl(OH)4 – NaOH – H2O at 50, 70 and 90°C.
The results of laboratory studies on super deep desilication of alumina liquors based on hidrocarboalyuminat calcium supplements 4CaO×Al2O3×0,5CO2×11H2O in advance of entering into the process of working hydrogranat sludge. Obtained qualitatively new alumina liquors with a silicon module (weight ratio Al2O3 / SiO2) of 50000 units. Impact of type-ahead hydrogranat sludge to a desilication depth given from the viewpoint of heterogeneous catalysis. The results obtained can be used to solve the problem of diversification of production in the complex processing of phosphogypsum in the synthesis calcium hydrocarboaluminates on the basis of fosfomel.
Results of investigations of the conversion methods of processing of large-scale fertilizer production of waste – phosphogypsum to ammonium sulfate and calcium carbonate (phosphomel). It is shown that, based on fosfomel can be synthesized by an innovative product multi-purpose – hydrocarboaluminates calcium 4CaO×Al2O3×nCO2×11H2O; the ways of effective use of hydrocarboaluminates calcium in the various sectors of the economy.
Materials of calculation of solubility of aluminum hydroxide in the system Na2O – K2O – Al2O3 – H2O, by data of the solubility in the private sections of this system for a wide range of compositions aluminate solutions by the content of alkaline components are presented. It is shown that the solubility of aluminum hydroxide in the range of concentration of alkaline components from 1,29 mol/l to 1,94 mol/l is a linear function of the mol fraction of one of them. The results of experimental researches on decomposition of aluminate solutions are given. Significant increase of the degree of decomposition of aluminate solutions in per cents of the theoretical values with growth of mol fraction of K2O in a mixture of alkaline components has been established.
The materials of mass transfer kinetic analysis of complicated by the establishment of adsorption equilibrium, during alumina liquor precipitation of alumina production. It is shown that the presence of strongly adsorbing impurities is one of the determinants of the intensity of the aluminum hydroxide chemical precipitation. The results of experimental studies on the alumina liquor precipitation with the participation of adsorption active components.
The role of thermodynamic and kinetic factors in the formation of the real structure of chemical precipitation. On the example of gibbsite precipitation from alkaline aluminate solutions is set to take place in parallel crystallization processes in the formation of production (rheological) properties of the solid phase formed during the chemical interaction is presented.
The design of a concentrating hydrocyclone «Water-only» for coal preparation is developed and tested. The scheme of automatic control is developed by hydrocyclone work. Automatic control application has allowed raising technological indices of concentration.
The results of studies on sulphatization refinement of mattes, containing platinum metals, it. The perspective of technology concentration of platinum metals from the products of processing man-made waste on a scheme «smelting matte – sulphatization» are justify.
The problem of increase of overall performance of powerful aluminum reduction pots at indemnification of metal losses is discussed during of magnet-dynamic movements. The scheme of asymmetric busbar is developed for increase of electrolysis productivity at the expense of MGD-stability.
The materials of the pilot study, which establishes the dependence of the kinetics of mass crystallization of aluminum hydroxide on the extent of metastable alkaline aluminate solutions. Shown that changes in the level of metastability of the environment of crystallization is the lag in time from changes in state parameters of physico-chemical system. The theoretical a justification of the transition from one level of the metastable state to another due to time constraints, changing the structure of unstable solutions.
At present time high grade and free-milling ore reserves have been exhausted in our country as well as in nearly all other countries in consequence of intensive development of nonferrous metal deposits. Relatively low-grade crude ore, which is deaf and therefore rebellious, is involved into processing. Moreover, after the collapse of the Soviet Union the more free-milling ores turned out to be abroad and so sulphide copper-zinc complex ores which are dressed with lower grade became the major sources of copper and zinc concentrate production in Russia. At the same time the metallurgical production is making higher and higher requirements to concentrate quality every year, and it is possible to meet the requirements only by application of mixed dressing, chemical, hydro- and pyrometallurgical technologies.
The task of the colour metallurgy is the complex utilization of the ore matirial and increase in volume of the production with fall of the material expenditures in parallel in unit of the production. During the sulphate ores refining and the nickel and copper ones they extract cobalt, pre- cious and the part of the rare metals, trying realize the very possible cobalts and small part of the ores raws transfer to the nickel product. However nickel can not be separated from copper completely with help of the flotation and that is why they get the sulphate nickel product which has the weight to 4 % of the copper and the copper sulphide concentration with weight 3-6 %. Together with nickel turn the part of the cobalt into the copper concentration. In the school and reference books there are little scientific well-founded and coordinated facts in phases compound of the stanes and finestanes and besides about formes of the presence of the cobalt in the called metallurgy products. It is necessary the deep experience in the study of the christall chemical nature of the finestanes phases for the improvement in extract of cobalt to the nickel product during the flotation process.
The method of automatic control over autogenous mill operation, allowing to raise productivity on an exit of a commodity class – 30 + 0,2 mm, and also to lower the expense of the electric power on ton of processed raw materials.
The article says about complex processing copper matte and copper-zinc materials are considered. The thermodynamic estimation this process is given. The new way of processing of copper-zinc materials and new metallurgical aggregate is offered.
Experimental results of thermal deposition of crystal hydrates of magnesium sulfate from a solution containing sulphates of alkali metals. Set of indicators as a function of the kinetically relevant factors. It was shown possible to describe the crystallization kinetics equation of magnesium sulphate topochemical processes and identify its characteristics.
Results of desalination siliceous minerals alkali-containing are presented by solutions. Testify that that decomposition kaolin occurs in thickness of the firm phase covered with crust hydroalumosilicate of sodium, without breaking its basic structure and without surplus of solvent. The dissolved surface remains to a constant that is one of conditions of applicability of the equation of Drozdova – Rotinjana.
A thermodynamic analysis of the system Se – H 2 O was prospect. Plotted dependences the concentrations of selenium oxyanions from the pH of the solution and polarization graphs for various materials of the anode. Draw conclusions about the regularities of selenium electroextraction from selenium solutions.
This work examined alloys which are belonged to trinary system Cu – Co – S. Macrostructural anaylysis of the above-referenced alloys was carried out. The impact of ferrum on this alloys was demonstrated.
The problem of the automated control of technological process of reduction aluminium process for superpower pots is discussed. The algorithm and system of optimum regulation of technological parameters by means of the alumina automated systems are developed. Offered computer neuron site model provides management efficiency.
A review of prospective industrial sources of platinum metals and modern technologies to process them has been done. The need for introducing new methods of involvement in the production of man-made platinum-containing materials has been substantiated.
Materials of the kinetic analysis of multistage mass-transfer process at decomposition of aluminate solutions in alumina production are presented. It is shown that in the mass-transfer equation concentration indicators which take into consideration distribution of reagents and products in a diffusive layer can play a role of effective concentration. Results of experimental researches of crystallization streams on a various fraction structure are resulted.
The results of studies on the intensification of the process of sorption extraction of iridium with highly basic anion exchanger AMP from sulfate solutions has been done. The effect of oxidant on the parameters of sorption of iridium has been described. Dependence of extraction of iridium in the sorbent from the temperature of the process and flowing anionite has been established. The perspective of the method of anionite sorption of platinum metals with highly basic sorbent AMP has been proved.
The scientific justification and development of the method for industrial synthesis of complex aluminates of alkaline earth metals is an innovative solution that determined several directions in the development of technology for complex processing of nepheline raw materials. It ensures the production of high-quality metallurgical alumina, the effective utilization of nepheline sludge and production of new types of multipurpose by-products. The modern development of these technical solutions is associated with ensuring the energy efficiency of the synthesis of hydrafed calcium carboaluminates (HCCA) and increasing the level of purification of aluminate solutions. The conditions for synthesizing HCCA with the use of calcareous materials of natural and technogenic origin have been experimentally determined, which makes it possible to isolate the average particle diameter as one of the determining factors of this process. The effect of the turnover of the hydrogarnet sludge on the removal of kinetic limitations in the process of deep desalination of aluminous solutions is theoretically justified. The conditions of a two-stage dosage of HCCA are experimentally determined. It is shown that the optimum ratio of the amount of the reagent supplied in the first and second stages is about 3: 2. At the same time, the maximum degree of precipitation of silica provides the production of aluminate solutions with a silicon module at the level of 95,000, which is achieved by using a HCCA synthesized based on chemically precipitated calcium carbonate in the processing of wastes from the production of mineral fertilizers.
The possibility of thickening and filtration for separation of heterogeneous disperse systems formed during the chemical conditioning of bauxite was investigated. It is shown that with increasing the ratio between liquid and solid phases of bauxite pulp thickening process indicators are improving. A similar influence provides of temperature increase of the process and the use of flocculants. The obtained results are compared with the indicators of condensation of red mud. The filter cloth was chosen for slurry concentrate bauxite, which provides the most rational regime filtration with the accumulation of sediment.
Complex mineral raw material, as alkali aluminum silicates, is an interest for aluminum industry, chemical industry and for the production of constructional materials. They are well represented in the earth's crust, characterized by the complexity of material composition and variable content of the main components such as alumina, silica and alkalies. They often occur where due to the geological conditions there is no bauxite, for instance, in the United States, Canada, Venezuela, Mexico, Iran, Egypt, Portugal, Spain, Bulgaria and other countries. At the present time for the Russian economy the nephelines from this list are the most valuable and have the great concern for the raw materials balance of the national aluminum industry. Because of limited reserves the bauxites proportion of alumina produced from nephelines by sintering is 40 % and in time this proportion will increase due to the involvement in the production of new deposits of alkali aluminum silicates. Many of foreign companies have also shown interest to the complex processing of ores. The investigation of technology is based on the method of sintering ore with limestone. As a result, the after-sintering mixture consists of alkali metal aluminates and dicalcium silicate; after-sintering mixture is leached by circulating alkaline aluminate solution, alumina, soda and potash are thrown out from the solution. Dicalcium silicate (nepheline sludge) is processed to Portland. For the investigated after-sintering mixture the tendency shows the increasing of optimum sintering temperature with the lowering Al 2 O 3 content. With the increasing of silicate module (SiO 2 / Al 3 O 3 ) of the initial alkali aluminum silicates charges the temperature of after-sintering mixture formation increases. After-sintering mixtures that are on base of alkali aluminum silicates have different microstructure and the degree of crystallization in which b-С 2 S and sodium aluminate is improved with a decrease of the aluminate phase amount. Results of investigations show a very limited solubility of aluminate phase in dicalcium silicate, which theoretically justifies a sufficiently high level of useful components chemical extraction in the processing of different types of alkali aluminum silicates by sintering.
The work reveals the ability of the Yakovlevskiy mine sinter ore to improve pelletizing of a sinter mix, to reduce its flow resistance in 4-5 times, to increase capacity of a sinter machine, to improve the sintering uniformity and sinter quality, to reduce consumption of agglomeration solid fuels and coke. Application of the Yakovlevskiy sinter ore moves sintering process to a modern technical level of charge in the sintering bed 500-600 mm in height without the use of expensive high-vacuum exhausters.
One of the problems to be solved in the course of exsolution of crystal sediments is to re-ceive products with desired technological properties. Two fundamentally different approaches can be applied for its resolution depending on method of supersaturation and requirements to the crystal sediments quality. In case of high supersaturation growth centers arise spontaneously and their number determines the properties of the final product to a large degree. The crystallization in the metastable region of solutions prevents spontaneous crystal nucleation and an introduc-tion of the seed phase becomes inevitable in this case. The nature of this phase determines the properties of the final product to some extent. During the real process there are mechanisms that disrupt the normal growth of crystals, causing distortion, leading to heterogeneous nucleation and recrystallization with degradation of seed material even. The line between these trends is the limiting supersaturation value, attrib-uted to the unit of phase interface. In this case the development of appropriate growth mecha-nisms is proportional to the deviation of the specific supersaturation of the solution from its value limit. The traditional source of heterogeneous nucleation is the mechanical interaction of the particles. The interaction probability is proportional to their concentration. Particles’ mass and their size becomes the most significant heterogeneous nucleation factor for seed particles of the same nature and morphology at the conditions of reproducible stream turbulence. Mathe-matical description of these trends has allowed to establish the dependence of the final particles’ size on the seed concentration in the feed pulp and to show the existence of a minimum number of particles of the final product. Experimental study of the of chemical sediments’ properties that depend on the seed amount, was carried out in relation to the breaking-up of aluminate solutions of alumina production. The process of selection of aluminum hydroxide has allowed to establish the amount of the seed aluminum hydrox-ide, resulting in a product of maximum size, and thus to confirm the theoretical conclusions.
The article analyses the research results of preliminary biological treatment by silicate bacteria influence on roasting process of refractory off-balance copper-molybdenum ore.
It is well known that lime is an effective additive which allows to increase the depth and speed of the extraction of alumina from bauxite by the Bayer process. The firing is one of the operations in thermochemical conditioning of bauxite, it is rational to enter directly on the lime-stone at firing of bauxite, eliminating the special operation of firing limestone and calcined material damping. In order to test this were carried out research on the firing of bauxite in the presence of calcium oxide, subsequent desiliconization of calcined bauxite and autoclave leaching bauxite concentrate.
In Russia and some other countries proposed various ways to the chemical enrichment of bauxite, which usually does not affect the question of regeneration of an alkaline solution of silica, or reduce it to the release of silica in the form of calcium silicate. While the technological circuits of the chemical enrichment of the return should include an alkaline solution, after regeneration, the following parties desiliconization bauxite. It is known that the chemical enrichment is accompanied by a secondary process – the formation of hydroaluminosilicates sodium, the rate of which depends on the concentration in the alkaline solution as aluminum oxide and silicon dioxide. This paper presents data a two-stage osazhdniya silica from an alkaline solution. In the first stage in the form of sodium hydro-aluminosilicates and second in the form of calcium silicate.
The results of laboratory studies on super deep desilication of alumina liquors based on hidrocarboalyuminat calcium supplements 4CaO×Al2O3×0,5CO2×11H2O in advance of entering into the process of working hydrogranat sludge. Obtained qualitatively new alumina liquors with a silicon module (weight ratio Al2O3/SiO2) of 50 000 units. Impact of type-ahead hydrogranat sludge to a desilication depth given from the viewpoint of heterogeneous catalysis.
The result of industrial tests of the technology super deep desiliconization of alumina liquors with fractional dose hydrocarboaluminate of calcium 4CaO×Al2O3×0,5CO2×11H2O. Due to this technology solution alumina liquors with higher silicon module (relative weight Al2O3/SiO2) without increasing lime carbonate expenditure.
The thermodynamic analysis of aluminium hydroxide dehydration during calcination process at alumina production is carried out. The calcination of aluminium hydroxide is possible at ordinary pressure and temperature value more than 600 K. Diaspor dehydration process is possible by way of freezeout of water as an ice, water rendering or heating till decomposition temperature.
Are considered the advantages and disadvantages of complex processing red mud to produce alumina, iron (cast iron) and cement on the area of alumina refineries and way of getting on them only transportable red mud – for shipping and recycling of new marketable products at operating enterprises.
The statistical analysis has allowed to reveal the additives essentially influencing process of formation of corundum. So, fluoric connections of sodium, calcium, aluminum, oxide of iron and chrome promote formation. Opposite influence is rendered oxide of sodium, by connections of lithium and a dioxide of the titan. Besides, influence of a dioxide of the titan and oxide of chrome is estimated.
The paper presents theoretically based requirements for the activation of synthetic gibbsite for maximum solubility of the activated product. The article describes the methodological foundations of gibbsite thermal activation and its effectiveness evaluation in terms of aluminate solutions decomposition. It is shown that to obtain high-saturation aluminate solutions, activation should provide generation of the reagent with highly-developed surface area, which is not identical to the structure of the deposited gibbsite. As a result of high-gradient thermal activation of synthetic gibbsite, it has been found that the targeted product develops predominantly an amorphous structure with a specific surface area up to 256 m2/ g, preserving its primary particle size. Activation products were investigated using modern methods of physical and chemical analysis. The experimental results confirmed the possibility of the activated product dissolution in the aluminate solution with a metastable compound and their spontaneous decomposition with aluminum hydroxide formation, characterized by high dispersion ability. It is shown, that a significant difference in kinetics and decomposition rates of solutions is connected with the use of a seed material with different particle size composition, which leads to the development of competing mechanisms, resulting in seed recrystallization, homogeneous and heterogeneous nucleation.
The question of magnesium oxide application for purification of aluminate liquors of aluminous production is in a complex considered. The two-phasic process is offered for providing of magnesium hydrocarbo- and sulfuraluminates formation by interaction of magnesium oxide with aluminate liquors under conditions, corresponding to parameters of aluminous production. High sorption activity of received compounds is defined with reference to organic substances of aluminate liquors.
Modern metallurgy pays more attention to chemical processes safety of staff and nature environment. One of the most hazardous branches in metallurgy is gold ores cyanidation. Researches on possibility to avoid cyanide leaching are carrying out during last thirty years. Cyanide competitors are thiosulphate and thiourea solvers. Within international cooperation between National Mineral Resources University and Lappeenranta University of Technology researches are devoted to tiosulphate leaching improvement. Main efforts are forwarded on process chemistry, however mass transfer processes of heterogenic systems are important as well. Therefore their optimization is planned to achieve by means of computer modeling based on particle image velocimetry.
More and more attention is paying to research of feasible cyanide alternative leaching techniques due to increasingly growing concern to Mother Nature. After some serious cyanide accidents some countries have campaigned to ban cyanide in gold mining industry. Political alignments and concern about environmental have been reasons to find good and less-toxic alternatives to cyanide. One of the most promising leach reagents is stated to be thiosulphate because of its benign properties. Moreover it is suitable for sulphide and carbonaceous ores which present a problem for cyanidation. In the present paper number of experiments on research of thiosulphate leaching kinetic study as well as pretreatment of gold concentrate by wet oxidation with following leaching tests is presented.
Sharp selectivity of hydrocarboaluminates of caustic-earth metals and magnesium oxide in relation to the most dangerous classes of the organic substances playing defining role in decrease in extent of decomposition level and deterioration of produced alumina properties– humic, carboxylic acids and high-molecular organic compounds are defined. Soda is good for humic acids sorption (about 40 %) also is inefficient for removal of carboxylic acids and high-molecular compounds. Harmful groups of organic substances generally provide chromaticity of aluminate liquors. The photometric analysis states an objective assessment of the content of the painted organic substances in relation to their initial quantity in aluminates liquors.
The behavior of impurities – colored organic compounds (COC) in aluminate liquors of Bayer process during electrolysis treatment was investigated. Experimental data for the impact of various technological parameters and conditions are found to reduce the content of COC to 50-80 %.
The results of synthesis hydrocarboalyuminates of calcium (GKAK) using carbonate reagents of different nature and size distribution. A high activity of the lime sludge from causticising soda and food processing conversion of phosphogypsum, which allows us to recommend them for use in the process of obtaining GKAK. Installed limiting stage of interaction of internal diffusion of the reactants.
The materials physical and chemical analysis of the reasons of instability particle size distribution of productional of aluminum hydroxide in the processing of bauxite by Bayer process. Shown that the frequency of changes in the properties precipitate Al(OH)3, formed during the precipitation of aluminate solutions determined by the dependence of the growth processes on the relative supersaturation of the system per unit area of the seed. Found determines the influence of concentration injected seed aluminum hydroxide and its active surface (which varies under the influence of impurities in the aluminate solution) on the parameters of the periodic changes in the properties of sediment.
Simmetry transformation crystalline structure proceeds by symmetry reactions. Unlike the chemical reactions that proceed in the liquids and the gases where ions or atoms move freely symmetry reactions proceed in solid bodies where structural units are set orderly.
In the article the basic principles of energy conservation and efficiency of the enterprises of metallurgy. The analysis of the energy saving potential in the metallurgical complex. We describe the stages of implementation of energy management, energy analysis of the structure of the enterprise.
Incidental concentrating of valuable elements in processing sulphide-copper ores yields supplementary semi-products enriched with osmium, rhenium, and selenium. Peculiar features of processing properties of rhenium, radiogenic osmium, and selenium are shown in this paper, as well as concentrators for rare microelements and ways of their extraction.
Dump slag dust products of man-made deposits of Norilsk region are a promising source of precious metals. Methods for concentrating precious and base metals in sediment cores of multiponds slag products are studied.