Casting of primary aluminum liquid into ingots; Degassing, deslagging, casting and cooling into ingots.; Production mix, at plant

Dataset description

This dataset describes material and energy use in the ingot casting stage inside aluminium smelters. The functional unit is a given mass of smelter grade aluminium ingots. The inventory is compiled from survey data for casthouses in several Chinese smelters reported in the paper and covers the main operations after liquid metal enters the casting shop, including degassing, deslagging, casting and cooling. Inputs include liquid aluminium from the electrolysis section, fuels such as natural gas for holding and heating, electricity for casting and handling equipment and small amounts of refining agents, mould release agents and packaging materials. Outputs consist of solidified ingots and metal losses in the form of dross and cropped ends. The inventory represents material flows and energy use from the point where liquid metal reaches the casthouse to ingot formation and packaging and does not include upstream electrolysis or downstream fabrication

Technology description

The system boundary of this unit process starts when liquid aluminium from the electrolysis section enters the casthouse and ends when ingots are solidified, cooled and packed. Liquid metal is transferred from the cells through launders or intermediate vessels to the casting station. In holding furnaces or troughs it is kept at the required temperature by fuel fired heating. At the refining stage suitable amounts of fluxes and mould release agents are added and the melt is stirred or treated with injected gas to remove dissolved gases and inclusions, which are separated as dross. The treated metal flows into ingot moulds or continuous casting equipment and solidifies under water or air cooling to form ingots of the required size. After stripping, ingots are inspected and sorted. Cropped ends and off specification ingots are collected and normally returned to the melting system for recycling. Acceptable ingots are bundled and stacked using asbestos rope, steel straps and clamps to facilitate storage and transport. Direct inputs to the system are a defined mass of liquid aluminium, fuels for holding and casting, electricity for casting lines and handling equipment and small amounts of fluxes, release agents and packaging materials. Direct outputs are smelter grade ingots, dross and metal losses in the form of cropped ends. Off site storage, transport and further processing are not included in this unit process.

Geographic context

The study builds a full chain model for the Chinese primary aluminum system. For the casting stage it uses survey data from casthouses in several smelters and constructs a national average inventory without distinguishing individual locations. This dataset therefore represents a weighted average of ingot casting workshops in the main aluminum producing regions of China and can be used as a generic description of the casting process under Chinese conditions.

Record

Classification

ILCD · C · Manufacturing; ILCD · 24 · Manufacture of basic metals; ILCD · 242 · Manufacture of basic precious and other non-ferrous metals; ILCD · 2420 · Manufacture of basic precious and other non-ferrous metals