Synthesis of Porous Material from Coal Gasification Fine Slag Residual Carbon and Its Application in Removal of Methylene Blue

A large amount of coal gasification slag is produced every year in China. However, most of the current disposal is into landfills, which causes serious harm to the environment. In this research, coal gasification fine slag residual carbon porous material (GFSA) was prepared using gasification fine slag foam flotation obtained carbon residue (GFSF) as raw material and an adsorbent to carry out an adsorption test on waste liquid containing methylene blue (MB). The effects of activation parameters (GFSF/KOH ratio mass ratio, activation temperature, and activation time) on the cation exchange capacity (CEC) of GFSA were investigated. The total specific surface area and pore volume of GSFA with the highest CEC were 574.02 m2/g and 0.467 cm3/g, respectively. The degree of pore formation had an important effect on CEC. The maximum adsorption capacity of GFSA on MB was 19.18 mg/g in the MB adsorption test. The effects of pH, adsorption time, amount of adsorbent, and initial MB concentration on adsorption efficiency were studied. Langmuir isotherm and quasi second-order kinetic model have a good fitting effect on the adsorption isotherm and kinetic model of MB.

Development of flotation machine impeller on the base of additive technologies

The constant increase in the consumption of ferrous, non-ferrous, precious and rare metals in the national economy requires an increase in the efficiency of minerals mining and processing. One of the main methods of enrichment used in the technological process of processing various ores is foam flotation. The authors provide a brief description of this process and analysis of various designs of flotation machines. The article is devoted to the modernization of the aeration unit of flotation machines with “RIF” design. It is noted that the design of such machines effectively uses the modular principle of assembly aggregates, which allows you to upgrade individual unit, increasing the efficiency of the machine as a whole. The main part of this unit is an impeller – the most complex and fast – wearing part. The paper analyzes various designs of impellers and their manufacturing technologies. It is noted that in the existing designs of flotation machines, the impellers are made of steel. It is proposed to replace this material with polyurethane, which has become widely used as a structural material due to the emergence of additive technologies in the production of various parts. This material has a relatively low cost and has an increased resistance to wear. The article formulates the main requirements for the most important operations of the technological process of impeller manufacturing. For this purpose, a 3D model of the upgraded impeller design was developed in the SolidWorks 3D computer-aided design system. The authors propose an additive technology for layer-by-layer production of an impeller on a 3D printer using the Ultimaker Cura slicer program. For the manufacture of the proposed design of the impeller made of polyurethane, the production technology was developed by the method of layer-by-layer deposition method of Fused Deposition Modeling (FDM).

DETERMINATION OF THE DEPENDENCE OF THE SIZE OF THE FLOATED PARTICLES ON THEIR PROPERTIES AND THE HYDRODYNAMICS OF THE FLOTATION CHAMBER

It is noted that medium-sized particles have the highest flotation rate. Grains of the boundary classes of the size range have a reduced floatability, and they account for more than 50% of all losses of extracted minerals during flotation. The stability conditions of the particle - bubble flotation unit in the chamber of the foam flotation machine are considered. The effect of perturbations of the bubble surface on the size of the floated particles is studied. The amplitude of the initial deformation of the surface and the amplitude of the initial deformation rate of the bubble surface were determined depending on the energy of the turbulent pulsations of the environmental liquid. It is established that the rate of energy dissipation in the chamber of the flotation machine has a moderate effect on the size of the extracted grains. The influence of the surface properties of mineral particles and their mass on the upper value of the particle size range is studied. It is shown that the hydrophobicity of the surface has a significant effect on the size of the mineral particles that remain in contact with the gas phase. The main parameter that characterizes the effect of the hydrophobicity of the surface of the floated particles on the value of the separation force can be the value of the advancing contact angle.

Hydrometallurgical processing of technogenic finely dispersed fluorocarbon-containing raw materials of primary aluminum production

The purpose of the paper is to determine the conditions for the maximum transition of fluorine from the technogenic raw materials of primary aluminum production (mature sludge) into solution under alkaline leaching. The object of research is the mature sludge, which is formed from technogenic finely dispersed materials of aluminum production in the baths with Soderberg anodes (tailings of coal foam flotation, gas cleaning sludge, electrostatic precipitator dust) and stored close to the enterprise. Analytical studies of the initial sample and leaching products have been carried out according to the certified methods using chemical, X-ray phase and titrimetric analysis methods. It is shown that, the main percentage of the three sludge components belongs to the dust of electrostatic precipitators (~ 79.7%) and coal foam flotation tailings (~ 15.8%). It has been determined that the gas cleaning sludge features the richest composition of useful components (in the sum of F, Na and Al ~ 63%). According to the data of X-ray phase analysis, the sludge sample from the sludge storage mainly contains cryolite (up to 78.7%), carbon (11.9%), calcium-magnesium carbonate from the dolomite series (4.44%), and trace amounts of corundum and fluorite. The results of the conducted experiments on fluorine leaching from the sludge sample by the caustic soda solution allow to estimate the main process parameters: temperature - 75–80°С, duration - 60 min, NaOH concentration - 3.0% (with the W:T ratio of 10:1 and a stirrer speed of ~ 1005– 1010 rpm). According to the analytical data on the chemical composition of leaching cake, the fluorine content in the solid phase reduces by 88.1%. The experiments carried out on alkaline leaching of fluorine from the sample of mature sludge formed under primary aluminum production by the electrolysis of cryolite-alumina melts in the baths with self-baking anodes allowed to find out that the maximum decrease of fluorine content in the sample is achieved under the conditions of maintaining the process parameters including temperature, duration, reagent concentration in optimal modes.

Composition and processing of sulphide lead-zinc ores from Chaabet El-Hamra mine (Setif, Algeria)

Purpose. In order to fully exploit the metal and facilitate its method of processing, we need an accurate knowledge of its composition, granular distribution, and association with unimportant and penalizing elements that we would like to get rid of, compared to the distribution of the element to extract by flotation method. Methodology. The present experimental work proposes an approach to the mineralogical, chemical and particle size characterization, several analyzes have been carried out by Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM/EDS), X-ray Diffraction (XRD), Optical Microscopy (OM), Particle Size-Fraction Analysis (PSFA), and X-ray Fluorescence (XRF). These analyzes were submitted on samples of lead-zinc of different sizes as well as well-prepared fine powder of this ore; the zinc content of the raw material is about 5% Zn. Findings. The results obtained by the mineralogical characterization and the particle size analysis reveal a very varied and irregular texture of the ore, consisting mainly of sulphides (sphalerite, galena, pyrite, marcasite), associated with carbonate gangue, mainly dolomite and calcite. The theoretical dimensions of the particles found in the fine grain size classes [-1 +0.053] mm. In addition, the conditions of the pulp using the following reagents: CuSO4 activator, PAX collector, CaO regulator and the pine oil foamed, along with a pH modifier between 10.5 and 12 (11.8 optimal), improve the content of sulphide minerals, and increased the concentrate of sphalerite (ZnS) by foam Flotation with a maximum recovery and economically appropriate content (54% Zn concentrate). Originality. Depending on the results of the analysis performed and the complete collection of data obtained in the laboratory, we aim to optimize the process of treating lead-zinc sulphide ore and give a more detailed reference source to specialists, researchers and metallurgists in field of mining in general and in the treatment of polymetallic lead-zinc ore in the area studied in particular. Practical value. Benefit the values of beneficial minerals (concentrate of zinc and others sulphide), from different types of raw materials. The latter focuses on flotation as the main successful technique in the extraction of this type of lead-zinc minerals, but it requires constant research and careful examination of its elements and values in order to excel in this field of polymetallic-sulphide ore processing.

APPLICATION OF INORGANIC REAGENTS-MODIFIERS FOR THE EXTRACTION OF SULPHUR-CONTAINING IMPURITIES IN THE FLOTATION OF GAS COALS

The relevance of the research lies in the need to remove sulphur-containing compounds from coal raw materials at the lowest cost to reduce the environmental load in the areas of coal use. The object of the study is coals of the “G” brand of the Kuznetsk basin of the Kirov mine. The subject of the study is the petrographic and chemical composition of coals, the content of sulphur impurities. The aim of the study is to develop selective reagent flotation modes using inorganic reagents-modifiers. Research objectives: – to determine the petrographic and chemical composition of coals; – to conduct flotation studies using the foam flotation method; – to evaluate the effect of inorganic reagents-modifiers on the φ - potential and hydration of the coal surface; – to determine the mechanism of modifiers’ action on the depression of sulphur-containing impurities of coals. Methodology and methods of research. A complex of physical, chemical and physico-chemical research methods has been used in the work. The degree of scientific development of the topic. A promising direction for reducing sulphur-containing emissions is to increase the selectivity of the flotation process by modifying the coal surface. Results: petrographic analysis of the studied coals has showed that the main micro-component is vitrinite (85 %); chemical analysis indicates that the humidity of the coals is 2.27 %, the ash content is 17.82 %, the yield of volatile substances is 32.90 %, the mass fraction of inorganic sulphur is 0.38 %, organic sulphur is 0.43 %. A comparative analysis of qualitative and quantitative indicators of coal flotation shows that the use of non-organic reagents-modifiers can significantly increase the extraction of sulfur into flotation waste. The analysis of the kinetics of changes in the electrode potential of pyrite indicates an increase in the potential values in the presence of these reagents and a decrease in the hydration of the pyrite surface. The obtained results indicate the expediency of using inorganic salts as modifier reagents that contribute to reducing the sulfur content in coal concentrates due to the depression of pyrite-containing impurities due to an increase in the hydration of their surface