Methodological approach to characterizing pollution of natural water bodies using satellite data with account of aggregation of finely dispersed mineral processing waste

The level of the environmental impact of the mining industry specifies the urgency of ecological management of the natural resources based on the satellite monitoring data. The high content of the suspended mineral particles in the industrial waters and the requirement to reduce their access to the natural water reservoirs determine the need to characterize the mininginduced pollution that can be carried out correctly with due account of the aggregate stability of dispersions. In spite of the theoretical concepts, prediction of the particles aggregation is limited by a lack of data on their interaction parameters. In order to parametrize the interactions in the mineral-water-mineral system it is proposed to use experimental data on aggregation of finely dispersed particles, obtained by the laser diffraction method in the equilibrium conditions. For this purpose the procedure of the experimental appraisal of the effective Hamaker constants has been elaborated using ores of developed deposits of the Kola mining complex as an example. The authors have studied the conditions of the surface layer of natural water reservoirs in the most industrially developed central part of the Murmansk region and defined characteristics of pollution with finely dispersed by-products of the mineral raw material treatment, according to the satellite observation data of the spatial distribution of the normalized difference turbidity index. The authors have established that the least propagation of the pollution into the natural water reservoirs is observed in the case of the apatite-nepheline ores processing by-products, which is explained by the effective aggregation of the finely dispersed nepheline particles. The proposed approach to apply data on mineral particles aggregation for interpretation of the satellite observations does not require carrying out in-situ observations and makes it possible to identify the mining-induced pollution of natural water reservoirs in industrial territories using suspended particles.

Effect of filler additions on pilot-scale extrusion coating of paperboard with PLA-based blends

We study the incorporation of minerals (talc, kaolin and surface-treated calcium carbonate) in paperboard coatings based on PLA to improve their performance, often limited by the low crystallinity and moderate gas barrier of the polymer. Masterbatches of PLA-based blends mixed with the mineral fillers were melt-blended in a twin-screw extruder and applied as a coating on paperboard in a pilot-scale unit operating at velocities up to 140 m/min. Thermal imaging was used during the extrusion coating and the effect of the fillers was investigated as far as processability and their effect on the mechanical performance. A reduction of neck-in and improved adhesion between the coating and the substrate were achieved at intermediate mineral loadings. Excess filler and low coating weight generated pinholes, leading to a reduction of the integrity and mechanical properties of the coatings. Overall, we define the performance window for continuous, pilot-scale coating of paperboard with a biopolyester filled with mineral particles, opening the opportunity to realize operations in industrial settings.

Impact of Naturally Occurring Asbestos on Asbestos Ban: Regulations and Experience of the Republic of Korea

This review examined the main issues debated in Korea regarding the production and use of materials containing naturally occurring asbestos (NOA) as impurities, and investigated the impacts of these debates on the asbestos ban, as well as the future implications. In Korea, incidents associated with the production and use of NOA-contaminated talc powders, construction rocks, serpentinites, and dolomite rocks raised public concern and led to accelerating the ban on asbestos. The main controversies concern policies on appropriate asbestos content limits, whether materials containing a trace amount of NOA should be banned, and the control of materials with high human exposure risk. To address recurring controversies, the implementation of preventive measures to manage elongated mineral particles and the use of transmission electron microscopy for more sensitive analysis need to be discussed, along with reaching social agreement on the controversial policies. To minimize the potential exposure to asbestos that may occur during the production and use of industrial minerals in the future, it is necessary to apply occupational exposure control measures and monitor the health effects of the relevant population groups. These national policies on NOA should be prepared based on close collaboration and discussion with policymakers, industry stakeholders, and related academic experts.

ATTEMPT TO IMPROVE THE OPERATING AND TECHNOLOGICAL PROPERTIES OF THE COMBINED GRAIN WASHING MACHINE

Washing machines are used in the production lines of grain cleaning departments of flour mills for thorough cleaning of the grain surface, in particular, its grooves from the remnants of organic and mineral dust, microorganisms and mold. In addition, the grain mass during washing is cleaned of hydrodynamically light and heavy impurities - chaff, seeds of waste plants, straw fragments, mineral particles in the form of sand, small stones, lumps of earth, as well as spores and wormwood seeds. At the same time, foreign odors of grain disappear.Experience in the operation of Ж9-БМА machines shows that along with many advantages, they have some disadvantages. In particular, the productivity of the machine 10 t / h does not correspond to the productivity of the conjugated technological equipment of the production line, and the specific water consumption for washing grain is 1.8… 2.0 l / kg, which is too much in modern conditions of acute shortage of drinking water. Enterprises to abandon the use of washing machines. In addition, certain problems and inconveniences are caused by the design of the sieve shell of the impression column. Stamped sieves with scaly asymmetric holes have a low coefficient of living cross section, which complicates the process of dehydration of washed grain, quickly corrode and rub, require special attention during installation or replacement. Therefore, an attempt is made to eliminate these shortcomings.In particular, the reduction of water consumption is achieved due to the elimination of the grain hydraulic conveyor during its transfer from the washing bath to the pressure column. For this purpose, a device for mechanical overloading of grain by a rotary bucket device located within the alloy chamber is used. At the same time, attention was paid to the separation of light organic impurities from the grain. This decision needs further explanation.The functional diagram shows that the initial grain mixture enters the receiving device, which feeds it with a minimum vertical speed into the ascending water streams created by the screws of two grain augers rotating with the same frequency in the opposite direction. The augers pick up the grain and, keeping it afloat in a suspended state, mix it with the water of the washing bath. At the same time the grain is washed and particles are separated from it, which differ from it in terms of density: mineral impurities begin to sink, fall down and through the longitudinal slit in the auger trough fall into the area of the auger for mineral impurities. This auger transports the "stones" in the opposite direction to the funnel with the ejector of the hydrotransporter of mineral particles. Light impurities, during the transportation of grain by grain augers, float to the surface of the water, the level of which in the washing bath is maintained up to the axis of the augers. Together with grain and water, these impurities are pushed out of the bath into the alloy chamber.In the chamber, in the transverse direction, a pipe with a longitudinal absorption slot is installed, the lower edge of which is immersed in water so that the upper layer of water merges into this slot together with light impurities that have surfaced in the washing bath. The amount of water that fuses light impurities can be adjusted by the depth of immersion in water of the lower edge of the absorption hole. To do this, the pipe is rotated relative to its axis with a special handle with a clamp and a pointing scale. One end of the pipe is closed by a plug, and the other passes through a hole in the wall and drains the water with light impurities into the sink sump. The described device provides almost complete removal of light impurities and minimal consumption of floating water. This solution is in the invention according to the copyright certificate 701708404, developed by specialists of the department TOZV. In addition, certain problems and inconveniences are caused by the design of the sieve shell of the squeezing column. Dirt particles tend to stick to the outer surface of the sieve cylinder and block its holes. This can slow down and even stop the separation of water by centrifugation. Therefore, the upper outer surface of the cylinder is washed with water, which in automatic mode is periodically fed to the sieve by the control device and the solenoid valve. It also saves water.