As UC Rusal’s largest aluminum facility, the Krasnoyarsk (KRAZ) aluminum smelter in Krasnoyarsk, Russia, has become a significant site for innovation within the company with improvements ongoing. In 2018, the company commissioned a new casting complex there for the production of large diameter billet. The company invested US$40 million in the construction of the casthouse and the purchase and installation of new equipment. Adjustments and startup activities are still in process, but in the short term, the casting complex will achieve a capacity of 120,000 tonnes of aluminum billet per year.
Smelter Profile
KRAZ has an annual primary aluminum production rate exceeding 1 million tonnes, with final product goods totaling 1,011,098 tpy. It produces 24% of Russian aluminum and 2.4% of aluminum globally. The smelter includes: 25 potrooms (including one potroom producing high purity aluminum), three casthouses, anode paste and coke calcination areas, and a fluoride production area. Currently the range of products includes small ingots (15 kg), T-bars, slab (in 1xxx, 3xxx, and 8xxx series), and now billet with the installation of the new casting area. The main source of energy for KRAZ is the Krasnoyarsk hydroelectric power plant.
The majority (about 70%) of the potlines at KRAZ implement EcoSøderberg technology, which was developed at Rusal’s Krasnoyarsk-based Engineering and Technology Centre. The EcoSøderberg technology allows for the upgrade of Søderburg top-worked cells with modifications to the structural design and improvements to the gas manifold and afterburner systems. The switch to the upgraded cell technology has allowed Rusal to reduce emissions of fluorinated compounds and tars.
As a whole, Rusal pays significant attention to setting high environmental and safety standards, with all of its facilities, complying with legal and regulatory requirements for occupational health, industrial, and fire safety. For example, KRAZ is certified for ISO 14001:2004 (international standard of environmental management system), ISO 9001 and ISO/TS 16949 (international standard of quality system), and OHSAS 18001 (international standard of health and safety system).
Billet Casting Line
The new casting complex was installed in casthouse No. 1 at KRAZ, the layout of which was modified to accommodate the new equipment. Installation and calibration of this equipment took two years. The casting area includes two 70 tonne tilting furnaces, an in-line degasser and filtration system, a casting mold assembly area, a new casting pit, continuous homogenization furnaces, and an automatic packaging system.
Molten metal from the potroom is fed directly into one of the two holding furnaces supplied by the Russian company, Research and Production Centre of Magnetic Hydrodynamics (MHD). Alloying elements are added to the melt (such as Cu, Cr, Mg, Si, and Mn) and then mixed using a MHD stirring system to achieve a homogeneous chemical composition. Finally, the alloy is refined with flux agents and argon, and a special furnace tending machine removes slag from the melt surface. After this, the same furnace is used for casting.
The casting pit features a 16 m hydraulic cylinder immersed at a depth of 27 m (equivalent to a nine story building). The Wagstaff casting machine has a lifting power of over 85 tons with a maximum casting length of 7,800 mm (276 inches). It is capable of producing 120,000 tons of billet per year. The casting pit is designed primarily for hard alloys of the 6xxx series in billet diameters ranging from 8 to 18 inches. The ability to produce 18 inch billet is a record for the Russian aluminum industry. The target applications for this new capacity include forging stock and the building and construction markets.
Special ultrasonic equipment is used for quality inspection and to study whether there are any cracks, pinholes, or extraneous deposits in the billet. Apart from that, a chemical and spectrometric analysis of the alloy is undertaken by the quality audit system of the company’s central industrial laboratory (audit samples show the content of metals and other elements in the alloy).
The complex also includes a homogenizing line from SECO/Warwick consisting of a homogenizing furnace, cooling station, sawing system, and packaging line. The homogenization furnace can simultaneously accommodate 61 billets, with a maximum tonnage of 120 tons. Total homogenizing capacity is 160,000 tons per year.
According to Rusal, all the equipment chosen for the new casting line was carefully selected before the purchase. The suppliers were picked for their high-quality and productivity standards. The companies provided not only delivery of equipment along with technology and associated devices, assembly, and startup, but also service support, technical training, testing, research in industrial and laboratory conditions, and analysis.
With the launch of the new casting complex and its increased billet size, Rusal is committed to meeting the growing billet demand globally. This includes demand for larger diameter billet for the growing transportation market along with increasing development of applications (such as automotive body-in-white, high speed trains, etc.).
Training: All the equipment purchased for the billet casting line was completely new for the casting personnel at KRAZ. In order to ensure the efficient and safe operation of the equipment, Rusal recognized the importance of all personnel being thoroughly trained before the launch of the casting complex. Therefore, 20 of the casting pit operators and production managers traveled to Wagstaff’s facility in Spokane Valley, WA, for training, as well as further training at the Novokuznetsk aluminum smelter (which already produces billet, though in smaller sizes). The participants were taught about equipment operations, safety rules, troubleshooting, cast analysis, and documentation procedure of the new casting equipment. In addition, Wagstaff personnel continue to work at the KRAZ site in order to verify that the equipment meets operational expectations.
Value-Added Products
One of Rusal’s main goals is to increase the sale of value-added products to 60% of its product mix by 2021, from its current 47% share. In order to achieve this, Rusal has implemented a number of projects throughout its facilities. In 2017, the company commissioned a new Properzi wire rod mill and four convection furnaces for the hardening of wire rods at the Kandalaksha aluminum smelter and completed the modernization of the Befesa-2 line for standard alloyed ingot production at the Irkutsk aluminum smelter.
The installation of the new billet casting complex at KRAZ continues Rusal’s path toward this goal. The complex has not increased capacity at the site (the KRAZ smelter has remained at the level of 1 million tons of capacity for the last ten years). Instead, it is enhancing the share of products with added value. The casting complex redistributes capacities, helping the smelter to increase its share of value-added products to 55% of its total output. In addition, the ratio between prime aluminum and alloyed aluminum will change. According to production targets for casthouse No. 1, alloyed aluminum products will make up 60% of the total output, with the remaining 40% left for prime aluminum. This notable increase in value-added production provides a corresponding increase in quality.
Editor’s Note: This article first appeared in the October 2018 issue of Light Metal Age. To receive the current issue, please subscribe.