Aluminum Plant Research Articles

Analysis and Countermeasures of Wind Power Accommodation by Aluminum Electrolysis Pot-Lines in China

The unit energy consumption and its price have become the main obstacles for the future development of the aluminum electrolysis industry in China. Meanwhile, wind power is widely being abandoned because of its instability. In this study, a novel idea for wind power accommodation is proposed to achieve a win-win situation: the idea is for nearby aluminum electrolysis plants to absorb the wind power. The features of the wind power distribution and aluminum electrolysis industry are first summarized, and the concept of wind power accommodation by the aluminum industry is introduced. Then, based on the characteristics of aluminum reduction cells, the key problems, including the bus-bar status, thermal balance, and magnetohydrodynamics instabilities, are analyzed. In addition, a whole accommodation implementation plan for wind power by aluminum reduction is introduced to explain the theoretical value of accommodation, evaluation of the reduction cells, and the industrial experiment scheme. A numerical simulation of a typical scenario proves that there is large accommodation potential for the aluminum reduction cells. Aluminum electrolysis can accommodate wind power and remain stable under the proper technique and accommodation scheme, which will provide promising benefits for the aluminum plant and the wind energy plant.

Use of moss biomonitors for turbulent transport coefficient estimation for industrial emissions

The important mechanism transporting substances in the surface layer of the atmosphere is turbulent diffusion. The intensity of turbulent transport is characterized by the turbulent diffusion coefficient. Calculation is a difficult task without a unique characterization. Distinguished turbulent models of atmospheric flow have been developed for particular atmospheric states and simple landscapes. These restrictions complicate the use of such models when assessing the distribution of industrial emissions in the atmosphere. The aims of the present work are to (i) develop a semi-empirical method for estimating the turbulent diffusion coefficient of the emissions of large industries, and (ii) study the turbulence intensity dependence of fundamental factors: the wind speed and landscape. The method relies on the distribution function of the concentration of contaminants measured along any direction of the altitude of a point source. Epiphytic mosses (Pylaisia polyantha, Sanionia uncinata) were used with an exposure time of 3 years. The chemical contents of the mosses were determined by neutron activation analysis and atomic emissive spectrometry. It is shown that in the territories of the coal-fired thermal power station and aluminum plant, the average values of the turbulent transport coefficient at heights above 1 m are k1¯=0.15 m2/s and k1¯=0.02 m2/s respectively. High turbulence within the location of the thermal power station is explained by obstacles of various heights and a higher wind speed. The proposed method is useful for the estimation and forecast of the spatial distribution of emissions from large industries and for determining the zones of their influence.

БИОХИМИЧЕСКАЯ ХАРАКТЕРИСТИКА ЭССЕНЦИАЛЬНЫХ НУТРИЕНТОВ КАК НАУЧНАЯ ОСНОВА ДЛЯ ОПРЕДЕЛЕНИЯ ФУНКЦИОНАЛЬНЫХ СВОЙСТВ СПЕЦИАЛИЗИРОВАННЫХ ПРОДУКТОВ И МЕХАНИЗМОВ ИХ ДЕЙСТВИЯ НА ОБМЕННЫЕ ПРОЦЕССЫ

Aim. To analyze biochemical functions and vitamins and their metabolites in order to provide scientific justification and determination of functionality of a new specialized product – fortified drink supplemented with beta-carotene and pectin for optimization of medical and preventive nutrition for iron and steel plant workers. The rationale of the study is associated with the necessity to optimize the diet of workers exposed to occupational health hazard in order to prevent occupational diseases, improve working capacity, and maintain health. Materials and Methods. We used theoretical analysis as well as data mining for analytical review of literature and our own studies. The work involved instrumental methods for assessment of quality, effectiveness, and functionality of the specialized products; the obtained data were statistically processed. Results and Discussion. The paper covers analytical review of materials dedicated to the role of essential nutrients – vitamins and their metabolites – in metabolic processes. The results of theoretical analysis became a basis of development of a formula of a new preventive drink considering biochemical characteristic of its agents and its effect on the body of a worker exposed to occupational health hazard. The regulated nutritional value indicators and consumption rates of the specialized products were determined. We obtained clinical evidence of effectiveness of the drink introduced into a diet of aluminum plant workers; clinical trials implied studies of lipid peroxidation products and activity of antioxidant protection enzymes. Dietary factor was proved to have a positive effect on the antioxidant potential and functional status of the body. The mechanisms of this effect were discussed. Conclusion. Supplementing the workers’ diet with the fortified drink containing beta-carotene and pectin effectively protects the body from the action of xenobiotics and contributes to health promotion and prevention of occupational diseases.

ANALYSIS AND FORECAST OF ACCIDENT RATE OF 6 – 10 KV DISTRIBUTION GRIDS AND POWER CONSUMERS IN THE MINING SECTOR

The main types of accidents in 6–10 kV power supply systems of mining enterprises are considered, such as short circuits, single-phase earth faults, phase failures, with their percentage relationships established. Mining enterprises are divided into three groups: open-cut mining enterprises (quarries and open coal pits); enterprises for extraction of minerals by underground method (underground coal and ore mines); mining & processing enterprises (concentrating factories, alumina plants, fertilizer production enterprises). The analysis of the accident rate of power supply systems of mining enterprises carried out for the period from 1995 to 2015 makes it possible to trace the dynamics of the above types of accidents and determine their most common form — single-phase earth fault. Over the above period, in the 6 – 10 kV power supply systems of quarries and open coal pits, underground coal and ore mines, and mining & processing enterprises, the share of single-phase earth faults was found to be within the following ranges: 65 – 76%; 60 – 69%; 58 – 67%, respectively. The greatest increase in accidents during the period under review was observed in 6 –10 kV power supply systems of quarries and open coal pits; with the total accident rate having risen with a factor of 3.21 from 1995 to 2015. The accident rate growth factor for underground coal and ore mines, and mining & processing enterprises amounted to 2.06 and 2.72, respectively. The changes are shown in specifi c types of accidents and general accident rate in the systems of electricity supply to quarries and open pits, underground coal and ore mines, and mining & processing enterprises. It is established that in the 6 – 10 kV power supply systems of the above-mentioned mining enterprises, the changes in single-phase earth faults and general accident rate are described by linear equations. On the basis of established patterns, a forecast is made of the change in the accident rates in power supply systems of the mining enterprises under consideration up to the years 2020 ÷ 2025.

Assessing the effectiveness of a corporate environmental education program for primary aluminium industry workers in Brazil

The material of this research was developed from a study done in a production unit, denominated reduction III, of a primary aluminium industry, in the city of Ouro Preto, situated in the State of Minas Gerais, Brazil. The exploratory study evaluated the influence that environmental education training could exercise in controlling the pollution caused by the enterprise. The purpose of the project being that of training the workers of this unit, in a short time, on the subject of environmental protection. The pro-environmental training, in practice, benefits the technological monitoring system of pollution control in that aluminium plant. The methodological approach employed was a case study, with the registered data and documentation, of a specific project in furnace rooms 3 and 4 of reduction III. After the environmental training program, there was a definitive positive alteration in the environmental performance indicator graph, called 'open-door-time' of the furnaces. It showed more coherent figures. Although the ideal daily open-door-target time of 40 minutes was not achieved, the graph showed figures which closely approximated this ideal time. If there are continued investments in this environmental education program, the ideal target time is sure to be reached.

Assessing the effectiveness of a corporate environmental education program for primary aluminium industry workers in Brazil

The material of this research was developed from a study done in a production unit, denominated reduction III, of a primary aluminium industry, in the city of Ouro Preto, situated in the State of Minas Gerais, Brazil. The exploratory study evaluated the influence that environmental education training could exercise in controlling the pollution caused by the enterprise. The purpose of the project being that of training the workers of this unit, in a short time, on the subject of environmental protection. The pro-environmental training, in practice, benefits the technological monitoring system of pollution control in that aluminium plant. The methodological approach employed was a case study, with the registered data and documentation, of a specific project in furnace rooms 3 and 4 of reduction III. After the environmental training program, there was a definitive positive alteration in the environmental performance indicator graph, called 'open-door-time' of the furnaces. It showed more coherent figures. Although the ideal daily open-door-target time of 40 minutes was not achieved, the graph showed figures which closely approximated this ideal time. If there are continued investments in this environmental education program, the ideal target time is sure to be reached.

Recovery of Solid Carbonaceous Wastes at an Aluminium Plant Equipped with Electrolyte Tanks with Self-Baking Anode with an Upper Current Lead

In the article is discussed that in the production of aluminum by electrolytic method carbonaceous wastes are formed. Currently some of the waste is recycled for subsequent use in related industries. To a certain extent, the full processing is limited by a low price with the high cost of processing. It was suggested to consider the creation of a closed cycle for solid carbon by using solid carbonaceous wastes in the production of anode paste. There were presented the material balance, as well as the results of granulometric and chemical analyzes confirming the principal possibility of this approach.

ОБЗОР И СОСТОЯНИЕ ГОРНОЙ ОТРАСЛИ АЛЮМИНИЯ В МИРЕ И В РЕСПУБЛИКЕ ГВИНЕЕ

Aluminum is one of the most common metals in the earth’s crust. The mass concentration of aluminum in the earth’s crust according to various researchers is from 7,45 to 8,14%. Today, aluminum ranks is second in the world in terms of consumption among all metals, second only to steel, and the demand for it is constantly increasing. The main raw materials for processing aluminum plants are bauxites and nephelines. According to preliminary data of the International Institute of Aluminum, the world production of primary aluminum increased by 0,5% in 2016 and reached 58,167 million tons. The growth of the world’s population, the economic recovery, and the active urbanization of developing countries provide a stable demand for aluminum. Aluminum is widely used in construction, automotive, packaging and other areas. The growth in aluminum consumption is closely related to the growth in aluminum production. China is the leader of this metal producer. The company by the aluminum producer is Hongqiao. The pricing of metals on the world market is the London Metal Exchange LME, and aluminum prices will rise. The localization of the bauxite deposit on land is unevenly distributed; huge resources are concentrated in the tropical and subtropical areas. Among lateritic deposits, objects of the bowal type are of greatest industrial importance, and are widely distributed in Guinea, India. Brazil. In perspective, the Republic of Guinea can become a leader in the production of the world market. Bauxite in the territory of Guinea was first discovered by the A.Lacroix islands of the Loos archipelago at the beginning of the 20th century. Guinea has a very high quality inventory of bauxite more than half of the world’s resources. Given the pace of exploitation of bauxite in other countries, and in the coming decades, Guinea will become the main center for the production of alumina and even aluminum.

Atmospheric occurrence and health risks of PCDD/Fs, polychlorinated biphenyls, and polychlorinated naphthalenes by air inhalation in metallurgical plants.

Metallurgical plants are important sources of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs) and polychlorinated naphthalenes (PCNs). It is significant to evaluate the air levels and human risks of PCDD/Fs, PCBs and PCNs in metallurgical plants considering their adverse effects on human health and thousands of metallurgical plants being in operation in China. The estimated inhalation intakes of PCDD/Fs, PCBs, and PCNs together in eight iron ore sintering plants, three secondary copper plants, four secondary aluminum plants, and one secondary lead plant were 4.9-213.4, 21.4-4026.4, 28.7-630, and 11.7fgTEQkg-1day-1, respectively, and the corresponding cancer risks were estimated to be 8.7×10-7 to 3.8×10-5, 5.1×10-6 to 1.1×10-4, 3.8×10-6 to 7.1×10-4, and 2.1×10-6, respectively. The estimated cancer risk were higher than 100 per million people for three secondary aluminum and copper smelters among the sixteen metallurgical plants, indicating high cancer risks. Stack gas samples from metallurgical plants were also collected and analyzed for comparing their emission profiles with that of air samples. The comparison of PCDD/F, PCB and PCN profiles between air samples and stack gas samples by similarity calculation and principal component analysis suggested the influence of stack gas emissions from metallurgical plants on surrounding air. These results are helpful for understanding the exposure risk to PCDD/Fs, PCBs and PCNs in numerous metallurgical plants being operation in China.

Surface Activation of Industrial Aluminum Hydroxide for Preparing Sandy Alumina

The effect of chemical treatment of industrially produced aluminum hydroxide on its seed activity during decomposition and capacity for agglomeration is studied with the aim of preparing sandy alumina in Ural aluminum plants. It is shown that the most suitable reagent for activating aluminum hydroxide is aluminate solution. After two hours of treatment of seed aluminum hydroxide in an alkaline solution at 90°C, the degree of aluminate solution decomposition increases by 4–5%. It is revealed that with the use of production aluminum hydroxide activated in aluminate solution during agglomeration it is possible to reduce the content within it of fraction –45 μm from 25 to 5%.

Residual Fuel Oil Cracking Using Alumium Plant Sludges as Catalysts

Cracking residual fuel oil separated from a mixture of Azerbaijanian crude oils using catalysts based on aluminum plant sludges containing up to 50-70% Fe2O3 was investigated. It is shown that the yield of liquid products, including motor fuels, upon residual fuel oil cracking at 550 °C rises to 80 and 70 wt. %, respectively. Steam gasification of carbonized and partially reduced catalyst allows production of gas with hydrogen content of up to 72.84 vol. %.

High-Performance Concrete Incorporating Locally Available Industrial By-Products

AbstractThis paper presents the concept of industrial symbiosis in which four industries available locally (steel plant, thermal power plant, aluminum plant, and stone quarry) are connected with the concrete industry. By-products generated by these industries (slag, fly ash, red mud, and quarry dust) were activated with a small amount of clinker to form four concrete mixes. The heat of hydration and the autogenous shrinkage were monitored on the fresh concrete mixes. The chloride migration and electrical resistivity of the concrete were measured at different concrete ages over 91 days. Drying shrinkage was monitored for 56 days, and compressive strength was tested after 28 and 91 days. The concrete prepared with a high volume of fly ash, slag, red mud, and quarry dust had very low chloride migration coefficients and less drying shrinkage compared to concrete prepared with ordinary cement. The synergetic beneficial effect of these by-products is explained by their complementary chemistry and particle-size ...

Effective removal of emulsified oil from oily wastewater using in-situ generated metallic hydroxides from leaching solution of white mud

Leaching solution of white mud (LSWM), a form of industrial waste from alumina plants, was added to alkaline oily wastewater, and metallic hydroxides were in-situ generated (IGMHs). We evaluated the removal efficiency of emulsified oil by IGMHs from simulated alkali/surfactant/polymer flooding produced water. The influence of various factors, such as LSWM dosage, initial pH, temperature, and contact time on oil removal efficiency was investigated. It was found that approximately 95–99% of emulsified oil was successfully removed by the co-precipitation/adsorption process. In addition, highly basic conditions and lower temperatures were preferred for IGMHs to remove emulsified oil. Thermodynamic analysis showed that the co-precipitation/adsorption process was spontaneous, exothermic and physical in nature, involving weak interactions, such as electrostatic attraction, hydrogen bonding, and adhesive force between the emulsified oil droplets and the binding sites on the surface of IGMHs. It was observed that IGMHs lost approximately 18.9% adsorption capacity for emulsified oil after more than four cycles. Therefore, IGMHs could be used effectively for at least four cycles. Moreover, recovery of oil from oily wastewater could improve the economic viability of this treatment process.

A comparison of an audiometric screening survey with an in-depth research questionnaire for hearing loss and hearing loss risk factors

Objective: We assessed the reliability of a hearing risk factor screening survey used by hearing conservation programmes for noise-exposed workers. Design: We compared workers’ answers from the screening survey to their answers to a confidential research questionnaire regarding hearing loss risk factors. We calculated kappa statistics to test the correlation between yes/no questions in the research questionnaire compared to answers from 1 and 5 years of screening surveys. Study sample: We compared the screening survey and research questionnaire answers of 274 aluminum plant workers. Results: Most of the questions in the in-company screening survey showed fair to moderate agreement with the research questionnaire (kappa range: −0.02, 0.57). Workers’ answers to the screening survey had better correlation with the research questionnaire when we compared 5 years of screening answers. For nearly all questions, workers were more likely to respond affirmatively on the research questionnaire than the screening survey. Conclusions: Hearing conservation programmes should be aware that workers may underreport hearing loss risk factors and functional hearing status on an audiometric screening survey. Validating company screening tools could help provide more accurate information on hearing loss and risk factors.

Recycling of Electrolyzer Spent Carbon-Graphite Lining with Aluminum Fluoride Regeneration

The spent lining of aluminum electrolyzer is one of the most environmentally hazardous wastes of the aluminum industry due to its content of up to 0.2 wt.% cyanide and up to 40 wt.% fluorides. The majority of spent lining is accumulated near aluminum plants in specially equipped landfills, where it can interact with water and air, with formation of toxic compounds and alkaline solutions that could lead to ground water contamination. At the same time, spent lining is of specific value due to presence of fluoride and up to 30 wt.% carbon. Known technology for processing spent lining with preparation of cryolite in operation at some aluminum plants has lost its importance after introduction of dry gas cleaning and a change-over to electrolysis technology using acidic electrolytes. This has led to a substantial reduction of cryolite requirement. Therefore, at present more attention is devoted to technology for producing aluminium fluoride, including from spent lining. This article provides a brief review of known technology for processing aluminum electrolyzer spent lining. Technology is provided for preparing aluminium fluoride product containing fluorine of 55–59 wt.%; thus, there is a reduction in fresh AlF3 consumption of about 4–6 kg/ton Al. Laboratory test results are provided.

A new non-electrolytic aluminum extraction method

A new method of primary aluminum extraction from alumina was proposed. The method is based on the new reaction AlI3+(3/2)Zn=Al+(3/2)ZnI2. In its turn, the exchange reaction AlCl3+CaI2→AlI3+CaCl2 is used to get aluminum iodide from aluminum chloride—the product of alumina carbochlorination. These reactions were studied in laboratory experiments as well as additional reactions, which were needed for the main chemicals recycling: Cl2, ZnI2→Zn, CaCl2→CaI2. XRD and SEM methods were used to investigate the phases and morphology of the reaction's solid products. The global free energy minimization method was used for the chemical equation's calculations. It was shown that aluminum can be effectively extracted from alumina without electrolysis, extreme high temperature and expended chemicals. The estimated specific carbon consumption and CO2 atmospheric pollution rate have to be halves of such values for the contemporary aluminum plant powered by the coal power station.

Numerical simulation of flash vaporisation in alumina production

Flash vaporisation is one of the key processes in the production of alumina during which the saturated dissolution liquid with high temperature and pressure entered into the flash vaporisation vessel (FVV). The periodic vibration was existed in the 10th stage FVV of an alumina plant and the vibration amplitude could be reach 7–8 mm which is adverse for FVV. In this study, a self-compiled UDF programme on FLUENT was used to study the 3D simulations of flow, mass transfer and heat transfer of gas–liquid phases in the flash evaporator. We simulated the pressure field distribution, distributions of gas–liquid concentration, and flow state inside the evaporator. The aims are to deeply analyse the causes for the vibration inside the flash evaporator, to improve the multi-phase transport inside FVV from the perspective of engineering and fluid mechanics, and to eliminate the effect of vibration.

Occupational exposure to polycyclic aromatic hydrocarbons and lymphatic and hematopoietic neoplasms: a systematic review and meta-analysis of cohort studies.

Data on the risk of lymphatic and hematopoietic neoplasms among workers whose jobs entail high exposure to polycyclic aromatic hydrocarbons (PAH) are sparse, and mainly based on small-size studies. We carried out a systematic review of occupational cohort studies that reported results on incidence or mortality from Hodgkin lymphoma (HL), non-Hodgkin lymphoma (NHL), leukemia or multiple myeloma (MM) among workers exposed to PAH. We computed meta-analytic estimates using a random effect model. Meta-relative risk (meta-RR) was computed separately by each type of neoplasm, job or industry. We identified 41 studies (12 in iron and steel foundries, 11 in aluminum plant, 6 in cokeries, 6 in carbon electrode manufacturing, 2 on asphalt workers, 2 on creosote-exposed workers, 1 on tar distillery workers and 1 evaluating both tar distillery workers and roofers). No significant excess risk of any lymphatic and hematopoietic neoplasms was found among workers employed in jobs or industries entailing high PAH exposure. Among 18 meta-analytic estimates by job or industry and type of neoplasm, 16 were close to unit, i.e., between 0.72 and 1.27, whereas the meta-RR was 1.38 [95% confidence interval (CI) 0.95-2.01] for HL in foundry workers and 2.01 (95% CI 0.96-4.22) for NHL in workers exposed to creosote. There was no association between occupation entailing high PAH exposure and risk of MM or leukemia.

Extraction of vanadium and synthesis of vanadium pentaoxide from Bayer’s sludge

Wastes generated from the Bayer’s process serve as valuable resources for aluminum, vanadium, gallium, etc. This work aims to develop a environmentally acceptable and low-cost chemical leaching-cumpurification method for the recovery of vanadium sludge of Indian alumina plant (10–12% V2O5) and synthesize vanadium pentaoxide. The efficiency of leaching was evaluated by various lixiviants like acidified water, H2SO4, soda and NaOH against variation in pulp density and temperature. Maximum extraction (96%) vanadium was achieved using acidified water leaching at above ambient temperature in 1 h with 200 g/L pulp density following diffusion control model. Finally, the vanadium rich leach liquor was purified by steps of adsorption/precipitation etc., to remove with iron and silica to get vanadium pentaoxide. A high purity product of 99% V2O5 was obtained by allowing the adsorption at acidic pH followed by desorption and precipitation at 90°C.

Into the Wild: Oryza Species as Sources for Enhanced Nutrient Accumulation and Metal Tolerance in Rice.

Rice (Oryza sativa L.) is one of the most important crops in the world (Elert, 2014). However, rice grain production can be affected by nutritional status, depending on the cultivationmethod and soil type: high levels of metals such as aluminum (Al) and iron (Fe) decrease plant growth and yield, especially in acidic soils (Ricachenevsky et al., 2010; Kochian et al., 2015), while low nutrient use efficiency leads to increased fertilization needs (Koutroubas and Ntanos, 2003). Rice grains, which are key staple food for more than half of the world’s population, can accumulate toxic elements such as arsenic (As), or show low concentration of key nutrients to human nutrition, such as Fe and zinc (Zn) (Sperotto et al., 2012; Ricachenevsky et al., 2015; Clemens and Ma, 2016). Thus, attempts to improve metal tolerance, nutrient use efficiency, and nutrient accumulation in grains are likely to have an impact on both agriculture and rice grains nutritional value for consumption. Cultivated rice (O. sativa) is part of the Oryza genus, which is composed of 23 species, including the cultivated African rice Oryza glaberrima, plus 21 wild relatives (Jacquemin et al., 2013). These species show 11 different genome types (AA, BB, CC, BBCC, CCDD, EE, FF, GG, KKLL, HHJJ, HHKK; Lu et al., 2009; Jacquemin et al., 2013; Atwell et al., 2014), and have a pan-tropical distribution, growing in a broad range of environments (Atwell et al., 2014). Since O. sativa was domesticated from a limited number of O. rufipogon genotypes, its closest wild relative, it is estimated that only 10–20% of the genetic diversity found in wild species is present in cultivated rice germplasm (Zhu et al., 2007; Palmgren et al., 2014). Although many efforts were made to find natural variation within the rice germplasm that could improve nutrition-related traits in cultivated rice, the narrow genetic diversity can be a limiting factor (Li et al., 2014; Yan et al., 2016). Considering the diversity of rice wild species and their distinct growing environments (Atwell et al., 2014), we can expect that they will be adapted to different nutrient availabilities. Thus, wild relatives are a potential source of interesting alleles or even new mechanisms of metal and metalloid accumulation control. However, these genetic resources are almost unexplored, with very few studies screening these species for interesting phenotypes, especially for metal-related traits.