External exposure levels and fluoride content in the urine of workers at aluminium electrolysis

Introduction. In the context of large-scale modernization and intensification of aluminium production, it becomes relevant to assess the actual fluoride loads and the main factors that determine the occupational exposure of workers to fluorides for health risk analysis. Materials and methods. Monitoring studies of the content of hydrofluoride and aerosols of fluoride salts in the air of electrolysis shops were carried out with traditional and modernized technologies for producing aluminium and fluorine in urine in 108 workers of the primary professions and 35 people in the control group. Determination of the concentration of fluorides was carried out by photometric methods, and fluorine in urine - by ionometric methods. Results. The total concentration of fluoride compounds in the air of the modernized shops was 1.4-2.1 times lower than the values in traditional shops. The fluoride content in the urine of workers in these workshops ranged from 0.8 to 4.7 mg/l, 1.1-6.7 times higher than the level of the control group and 1.1-2.3 times the limit value of the biological exposure index. The highest external and internal fluoride loads and associated health risks are found in workers who maintain electrolyzers and anodes. A closer, noticeable (r = 0.644) correlation was found between the content of fluoride in urine and the levels of gaseous hydrofluoride in the air, indicating its predominant effect on workers compared to other determinants (total concentration of fluorides, seniority and age). Conclusion. The studies’ results indicate a high additional informative value and reliability of biomonitoring of fluoride in urine, which, combined with analysis of air pollution with fluorides, provides a completely objective assessment of the risk of exposure to workers. The presence of high levels of hydrofluoride in the air of electrolysis shops creates a higher occupational health risk for workers.

Increasing Resource Efficiency of Bauxites Using LIBS

The EU aluminium production from, e.g., bauxite is one of the backbones to support Europe’s green and digital transition. In support of sustainable bauxite exploration and mining, Laser Induced Breakdown Spectroscopy (LIBS) was used on the major facies of the karst bauxite deposits of SODICAPEI (Southern France). Our results showed that LIBS is a very promising technology to define the bottom and top layer of bauxite ores and to access critical parameters crucial for bauxite mining and processing. First LIBS tests were made on scandium standards to find appropriate Sc emission lines for future applications.

Industrial Production Technology for Aluminium Paste

Today, the development of aluminium industry is highly dynamic. Aluminium production rightly takes top positions in the global metal market. Unique properties of aluminium mean that it is widely used in various industries. The construction industry is no exception – here, aluminium is actively used as a gassing agent for production of steam-cured aerated concrete, which is produced by mixing Portland cement, sand, water and aluminium fine powder or aluminium paste. The main disadvantage of aluminium fine powder is its high degree of dusting: at certain air concentration levels, this becomes fire-and explosion-prone. This is the reason the producers add complex organic additives into their aluminium fine powder: to ensure lower dusting levels and produce an aluminium paste, which is safer to use. This work focuses on obtaining an aluminium paste with sufficient share of organic additives to ensure the efficient performance of aluminium paste as a gassing agent in the production of steam-cured aerated concrete. A number of tests were carried out on mixing aluminium fine powder with various organic additives (fatty additive; wetting agent and gassing kinetics stabiliser; dedusting agent) in different ratios. The paper analyses the quality of distribution of organic additives inside the finished product and studies the relevant gassing kinetics.

Comparative assessment of fluorine, sodium, and lithium distributions in snow cover in Siberia

Based on field studies of the snow cover and systematization and analysis of scientific data and technical literature data, the distributions of fluorine, sodium, and lithium, as elements included in the raw materials used for aluminum production, in the snow cover in areas proximal to Siberian aluminum smelters were considered. The results showed that the changes in concentrations of fluorine, sodium, and lithium in the snow cover near various plants have the same dispersion pattern, which can be described by an exponential relationship. Exponential relationships of diminishing concentration with distance from the emission source had high correlation coefficients. From the examples established by these relationships, an assumption was made that the behavior of these aerosols in the atmosphere is determined by the general physical and chemical properties, irrespective of the technologies and natural climatic regions of the plant locations. It is suggested that deposition of aerosols from industrial aluminium production can be achieved at a minimum distance from the plants or within the plant area through particle enlargement by various technological methods in aluminium production or by changing the atmospheric scattering capacity.