Effect of ore dressing on flotation of copper and arsenic minerals in sulphide ore processing

Monomineral flotation results showed that the use of a new reagent S-cyanoethyl N, N-diethyldithiocarbamate enhances the flotation activity of chalcopyrite, in contrast to flotation with butyl xanthate, and reduced the flotation ability of arsenopyrite, which makes this reagent promising for its use in the selective flotation of complex sulfide ores.

Modelling of the Chemical Halo of Dust Pollution Migration in Loparite Ore Tailings Storage Facilities

The article presents a study of the environmental impact of dusting tailing dumps of rare-metal ore dressing in the Murmansk region of Russia. The purpose of the study was to establish patterns in the atmochemical halo migration of the dust pollution of loparite ore dressing tailings. The geotechnical characteristics and material composition of the tailings material have been investigated. Potentially dusty areas identified. Models of dispersion of inorganic dust under different meteorological scenarios are constructed: at low wind load, normal and unfavorable meteorological conditions. The modeling of the spread of pollutants in the area exposed to dust at the storage site was carried out in the program for modeling atmospheric pollution Ecolog-4.60. Calculation of the dispersion of inorganic dust containing 20–70% SiO2 showed that the atmochemical halo of tailings dust pollution spreads over tens of kilometers, and already at a wind speed of about 8 m/s, the concentration of suspended solids at the border of the enterprise sanitary protection zone exceeds the maximum one-time maximum permissible concentration is 3–3.3 times, and under unfavorable meteorological conditions—Dusting reaches the boundaries of the residential area (inhabited locality Revda), located in the north-west of the enterprise, and exceeds the MPCm.o. 1.5 times.

MUNICIPAL WASTEWATER IN EXPERIMENTS ON RECLAMATION OF LOPARITE ORE DRESSING TAILINGS

Introduction. This paper discusses the effectiveness of using clarified municipal wastewater (CMW) and wastewater sludge (WS) to form stable phytocenoses at the waste storage facilities of the rare metal industry in Murmansk Region. The restoration of the vegetation cover at tailing dumps is limited by the low content of organic matter and associated nitrogen, and the low bioavailability of plant nutrients (K, Ca, Mg, P). The use of WS and other ameliorants of organic nature is a type of chemical amelioration aimed primarily at improving the edaphic properties of man-made soils. Methods. We examined the loparite ore dressing tailings sampled in the operating field of the tailing dump of a rare metal industry enterprise in the center of the Kola Peninsula. In the course of the study, we determined the suitability of the man-made soil for reclamation. To form seeded phytocenosis in a laboratory experiment, seeds of meadow fescue (Festuca pratensis Huds.) were used. The laboratory experiment involved the introduction of CMW, WS, a mixture of WS with silica clay into the soil, and a check. Analysis of the soil and plants was performed using inductively coupled plasma mass spectrometry. The quality of seeded cenosis was assessed according to the following parameters: green biomass, plant height, and projective cover. Results. The preliminary assessment of the man-made soil suitability for reclamation showed the following: the loparite ore dressing tailings have unfavorable characteristics both for the natural regeneration of the vegetation cover and biological reclamation. The introduction of ameliorants had a stimulating effect on the growth of terrestrial biomass during the formation of phytocenosis under laboratory conditions. The results of leaf analysis confirmed the effectiveness of the surface application of organic additives with regard to the loparite ore dressing tailings. Conclusion. In the laboratory experiment with the simulation of surface application, the stimulating effect of unconventional ameliorants (clarified municipal wastewater, wastewater sludge, and its mixture with silica clay) on the supply of nutrients to the reclaimed loparite ore dressing tailings was confirmed. The investigated ameliorants can be recognized as suitable for the biological reclamation of the dressing tailings of the rare metal industry, which does not require costly earthing and the application of protective polymer coatings.

OPTIMIZATION OF CONCRETE COMPOSITIONS WITH SECONDARY INDUSTRIAL PRODUCTS

Purpose. Analyze scientific publications on the existing problems of environmental pollution by secondary industrial products. Search for ways to solve these issues through the rational use of concrete in construction with additives of secondary industrial products, especially fine-grained ones. Determination of rational compositions of medium-strength concrete with the minimum required consumption of cement and filler from iron ore dressing wastes of mining and processing plants. Methodology. To achieve this goal, the experience of improving the structure and properties of concrete by introducing complex additives based on secondary industrial products into its composition is analyzed. The following materials were used for the research: Portland cement CEM 41.7 from Krivoy Rog; as a large aggregate – crushed granite with a maximum grain size of 20 mm; fine aggregate – river quartz sand; mineral additives – products of concentration of iron ores of the Southern Mining and Processing Plant. The experiment was carried out on certified equipment. Control specimens with a side of 10 cm were formed. The compressive strength of concrete was determined according to a standard procedure. Based on the results of the mathematical analysis, graphical dependences of the change in the optimized characteristics on the variable parameters – the consumption of cement, the products of concentration of iron ores and the plasticizer – were built. Findings. Based on the results of testing the samples, the calculation of mathematical models of the experiment was carried out and polynomials of the third degree were obtained for the optimized parameters – the average strength of the samples and the coefficient of efficiency of using cement. The following patterns can be distinguished. The strength of concrete depends to the greatest extent on the consumption of cement in the composition of the concrete mixture and increases significantly with an increase in its content within the studied limits. With an increase in the filler content in the studied range, the strength of concrete, and, accordingly, the coefficient of efficiency of using cement increases with a decrease in the content of cement in the composition of the concrete mixture. Originality. The studies carried out make it possible to determine the main regularities of increasing the efficiency of cement use when utilizing local secondary industrial products in concrete, namely, the introduction of iron ore dressing waste from mining and processing plants as a fine-grained additive in concrete. It was found that it is possible to obtain the required low concrete strength with a significantly lower cement consumption by ensuring a rational grain size composition of the concrete mixture components. Practical value. When designing concrete compositions with a high coefficient of cement utilization, it is necessary to use the obtained research results, providing cement savings and utilizing a significant amount of fine-grained secondary industrial products.

A Method of Ore Blending Based on the Quality of Beneficiation and Its Application in a Concentrator

Ore blending is an essential part of daily work in the concentrator. Qualified ore dressing products can make the ore dressing more smoothly. The existing ore blending modeling usually only considers the quality of ore blending products and ignores the effect of ore blending on ore dressing. This research proposes an ore blending modeling method based on the quality of the beneficiation concentrate. The relationship between the properties of ore blending products and the total concentrate recovery is fitted by the ABC-BP neural network algorithm, taken as the optimization goal to guarantee the quality of ore dressing products at the source. The ore blending system was developed and operated stably on the production site. The industrial test and actual production results have proved the effectiveness and reliability of this method.

Investigation of the solubility of dust particles in soil solution at different temperatures (on the example of the tailings of the loparite ores' concentration)

A number of large mining enterprises are located on the territory of the Murmansk region. Dusting overburden dumps and tailings storage sites leads to a complex of long-term consequences for the environment. The output of the silty fraction (-0.071 mm) of "stale" tailings of loparite ore dressing (the first field of the tailing dump) is about 22 %. The investigated material is represented by nepheline, microcline, aegirine; loparite, analcime are diagnosed in impurity quantities; the average content of cerium, lanthanum, neodymium - rare earth elements of the light group - 0.18, 0.03 and 0.015 %, respectively. In laboratory conditions, a simulation of the ingress of a fine fraction of loparite ore dressing tailings into the soil has been carried out; the interaction of tailings material with distilled water and water extract from conditionally background soil at different temperatures has been studied. In the course of the study, it has been found that the introduction of dissolved organic matter intensifies the processes of destruction and partial dissolution of the aluminosilicate matrix of rock-forming minerals; an intensive transition of rare earth elements and heavy metals into soluble forms has been recorded. The research results indicate the ecological danger of the finely dispersed material of "stale" tailings of loparite ore dressing due to the ingress of dust particles into the soil and their interaction with soil waters.