Carrying molten aluminium from furnace to casting stations
The illustrated launder runs as a refractory channel at floor level with lifting covers along its length and a branch where the flow splits. Two things happen to the metal on its way: it loses heat into the refractory and to the air, and it has to arrive at each casting station at a level and temperature the caster can control. A smelter cast-house energy study, a TMS paper on launder heat conduction and a Wagstaff patent on distribution launders each take one side of that.
Covers launders that distribute molten aluminium from furnaces to casting stations: heat loss through the refractory and surface, preheating, covers and insulation, temperature control at the casting table, and the structural behaviour of launders spanning a row of DC or EM casting stations. Stopper-rod pouring valves are on 113; rotary degassing on 132; molten metal pumps on 3226; flow control nozzles for steel casting on 499; non-ferrous continuous casting lines and their saws and withdrawal drives on 586, 2839 and 3256.
CNFX editorial research · Sources checked October 13, 2026 · 3 sources
Where the metal's heat goes: into the refractory first
Pakanati and Tveito, presenting at the TMS 2022 cast shop symposium, start from the casting table: liquid metal temperature there has to be controlled to avoid defects and keep DC casting stable.
The transient part is what matters at the start of a cast: a cold refractory channel draws heat from the first metal much faster than a soaked one, which is the case for preheating the launder before metal arrives (editorial reading of the TMS point).
Covers like the ones in the illustration address the surface loss from the open channel, preheating and insulation the refractory loss (editorial reading).
Point
Source
Simple analytical models can show the temperature loss from furnace through the casting line and help regulate the metal temperature entering the casting table
TMS 2022
Part of the loss is conjugate heat transfer between the refractory launder and the liquid metal
TMS 2022
Predicting the transient temperature field in the refractory during casting is therefore critical to predicting the liquid's temperature loss; their analytical model was compared with casting-trial data and 1D and 2D simulations
TMS 2022
Preventing heat loss from metal in launders saves energy and helps casting quality
ICSOBA 2024 (Bechtel)
The TMS item is a conference abstract; the full paper is in Light Metals 2022.
02
What a cast house saves: launder preheating 139, covering 58, insulation 36 MJ/t
Pavitrakar and Mathew of Bechtel quantified energy potential and savings in an aluminium smelter cast house (ICSOBA 2024).
The three launder-related items add up to 233 MJ/t, about 8% of the stated waste (Editorial calculation). For a 0.6 Mt/a cast house, the paper's reference size, that is about 140,000 GJ a year (Editorial calculation).
The authors note that a 0.6 Mt/a smelter cast house wastes around 35 MJ/s, up to 135 MJ/s at peak, assuming 30% maximum thermal efficiency, and propose reusing that heat for launder preheating among other uses.
Item (ICSOBA 2024)
MJ per tonne Al
Energy potential from incoming hot metal and fuel
4,611
Energy waste or loss
2,892 (around 63% of the potential)
Savings from launder preheating
139
Savings from effective launder covering
58
Savings from effective thermal insulation
36
Savings from scrap or alloy preheating
23
Minimum cast-house operating requirement
885
Savings are the authors' estimates for a smelter cast house; foundries and remelt plants differ in metal route and launder length.
03
Launders over casting stations: why they bow and how one design stops it
Wagstaff's patent US 5,316,071 (1994) addresses a distribution launder spanning a row of DC or EM casting stations, from which metal levels in the moulds below are measured.
The principle is to separate the hot refractory channel from the cold structure that has to stay straight: the refractory moves freely, the beam stays cool and straight, and the level sensors on it keep a fixed datum (editorial summary of the patent).
For a floor launder like the one illustrated, the same expansion problem shows up as gaps and joints between refractory sections rather than bowing, which is why sections and covers are separate pieces.
Point
US 5,316,071
What casting control needs
Molten metal level, drop rate and cooling rate closely monitored and controlled
Support
Launder supported at both ends and built strong enough for its own weight and the metal it carries
Why it bows
Metal flows along the bottom, so heat builds up more in the lower structure than the upper, bowing the launder; in extreme cases accurate level measurement becomes impossible
What did not work
Earlier attempts with structural reinforcement and launder cooling did not give acceptable results; water cooling is undesirable because of reactions
The design
Structural beam carrying spaced U-shaped refractory holders, about 21 in long with expansion gaps, which expand and contract without loading the beam; air-cooled holder walls; beam on a roller at one end; level sensors mounted on the beam
The closing sentence is an editorial reading of the illustration, not a statement from the patent.
04
What to give a launder supplier
Paste it into your enquiry below or into an email to a maker, then replace every bracket.
Give the alloy, metal flow rate, furnace and casting-station layout and distances, required metal temperature at the casting table, number of branches and casting stations, whether metal levels are measured from the launder, preheating means available, and maintenance access. Ask for the refractory materials and thermal properties, section length and expansion arrangement, cover design, preheating method and time, predicted temperature loss along the run, and support structure.
Explore company information and manufacturing capabilities, then discuss the scope of your project with a relevant supplier.
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Compiled and source-reviewed by the CNFX editorial team.
Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review
· Page last updated 13 October 2026
Buyer questions
How much energy do launder measures save in a cast house?
Bechtel's ICSOBA 2024 paper gives 139 MJ/t for launder preheating, 58 MJ/t for effective covering and 36 MJ/t for insulation in a smelter cast house. [1]
Why does launder refractory matter for metal temperature?
Pakanati and Tveito (TMS 2022) attribute part of the heat loss to conjugate heat transfer between refractory launder and liquid metal, so the refractory's transient temperature field must be predicted. [2]
Why do distribution launders bow?
US 5,316,071 explains that metal flowing along the bottom heats the lower structure more than the upper, bowing a launder supported at its ends and spoiling level measurement over the moulds. [3]
Sources and what still needs a direct check
Sources checked 2026-10-13. A smelter cast-house energy paper from ICSOBA 2024, a TMS 2022 abstract on launder heat conduction, and a Wagstaff patent on distribution launders.
