For its carbon department, the company is seeking to appoint three suitable vendors to provide services for induction furnaces, strategic anode baking furnaces refractory repairs, anode baking furnaces routine maintenance and anode baking furnaces building and the replacement of flue walls.
The carbon department manufacturers about 432 000 carbon anode blocks a year for the reduction process. It is made up of three main sections, namely the anode paste plant, the anode bake furnace and the anode rodding shop.
The anode bake furnace is made up of three baking furnaces with 136 sections and is used to bake the anodes. The anode rodding shop has three 5 t cast iron induction furnaces, which are used to mate the anode to a stem.
For the casthouse, Hillside Aluminium is seeking to appoint two suitable vendors to provide services to relining of launders and repairs, and relining of ladles and repairs.
"Molten liquid aluminium from the reduction pot rooms is transported about 2 km through the casthouse in 10 t ladles at around 750 °C to weighbridges and then into the holding furnaces. Each ladle is lined with refractories, which need to be replaced after 1 400 cycles of use. There are currently 20 ladles in circulation," the company says.
Tilt launders are used to transfer the molten aluminium from the ladles into the furnaces. These are movable and can be repaired and relined off-site. The furnace launders transfer the molten aluminium from the furnaces to the casting chains. These launder pieces are not movable and have to be repaired and/or relined on site, in situ, the company says.
"The request is to have a dedicated refractory casthouse service provider that will offer a turnkey solution for refractory services, which will include everything from ad hoc repairs, emergency repairs, scheduled and unscheduled relining, measuring, quality inspections, as well as ensuring constant and ready supply to the casthouse as the process is a continuous 24-hour operation."
Further, for the reduction department, Hillside Aluminium has called for two suitable vendors to provide services for pot relining, including producing relined shells, and cathode sealing, including producing sealed cathode blocks.
"The objective of the reduction department is to produce liquid aluminium. The plant consists of three pot lines with a total of 720 pots that produce liquid aluminium. Each reduction pot is used to produce liquid aluminium for a lifecycle of five to six years.
"The refractory pot relining workshop in the reduction department consists of six relining bays, with a seventh storage bay to ensure continuity of work. Pot shells are typically relined during the day shift within seven days, with the refractories left to cure overnight.
“During peak periods, the inclusion of a night shift team can reduce completion to five days, which will result in a maximum of one relined shell a day or seven shells a week.," Hillside Aluminium says.
The company adds that about 86 pots are planned to be relined during the 2022/23 financial year, to be followed by about 168 pots in the 2023/24 financial year.
Further, the cathode sealing workshop uses cast iron to join cathode blocks and cathode bars, working a 12-hour day shift, and 14 to 16 cathodes can be sealed a day. A night shift team will further increase this number. This facility can, therefore, provide sealed cathode blocks for more than seven pots a week.
The Hillside Aluminium smelter uses Aluminium Pechiney 30 (AP30) technology and produces 720 000 t/y of high-quality, primary aluminium for export markets.
"To be successfully considered for progression of this expression of interest, companies must meet various requirements, including that preference will be given to companies that have previous experience in rendering refractory services, such as furnace and induction furnace relining, ladle relining and related services."
Further, preference will be given to exempt microenterprises or qualifying small enterprises, in terms of the 2007 Codes of Good Practice and the company must employ South African personnel, preferably from the King Cetshwayo district municipality, for these services.
"The contractor must be in a position to work shifts as necessary and must adhere to in-house quality management and safety standards. Companies must also comply with all Covid-19 regulations and controls and must have valid company registration documentation," Hillside Aluminium says.