Machines and robots that remove slag and dross from molten metal · Hot-metal ladle skimmers after desulfurization, boom and rake kinematics, refractory-coated paddles, rail-guided aluminium furnace skimmers with cameras, robotic crucible stations, cycle time and in-furnace dross pressing
A slag skimming machine is a powered boom or robot that draws a refractory-protected paddle or rake across the surface of molten metal in a ladle, crucible or furnace to pull floating slag or dross over the lip into a slag pot or dross pan, keeping operators away from the hot face. Ask three things first: which vessel, metal and slag or dross the machine must clear and how the vessel is presented (tilted ladle, crucible, furnace door), what reach, motion and tool the boom or robot needs, and how far the cycle should be automated with lasers, cameras or level measurement.
Skimming machines and robots for removing slag from hot metal and steel ladles and dross from aluminium crucibles and furnaces: slewing and telescopic rake booms, rail-guided furnace skimmers, robotic skimming stations and their tools and guidance. Desulfurization reactors (see molten metal desulfurization reactor), manual hand skimmers, dross processing presses away from the furnace and slag pots are outside this page except where compared.
CNFX editorial research · Sources checked October 11, 2026 · 6 sources
US EPA AP-42 describes hot metal desulfurization in which reagents injected into the iron react with sulfur to form a floating slag that is skimmed off, in the torpedo car or ladle at a station in the BOF shop, with fumes collected by a hood over the ladle. US4526352A describes the conventional deslagging rake: an extendable boom on a column that slews about a vertical axis, with a downward skimming blade that can pivot at the boom end; the boom is run out over a tilted ladle and slag is removed by extending, retracting and tilting the boom or blade. It adds an auxiliary boom section and a rake pivoting on a second axis so slag can also be scraped from the ladle walls. [1][2]
US10132567B2 describes steel-ladle skimming with a hoe-type paddle that pulls slag into the slag pot, the use of a separate gas bubbling lance to drive remaining slag towards the paddle, and an improved paddle with a gas port: a welded steel framework of about 3/4–1 in plate coated in reinforced refractory, needed to stop it melting into the metal, and comparable in weight to the 3/4 in plate paddle it replaces so an existing machine can carry it while moving back and forth and side to side. [3]
Give the supplier the vessel types and sizes (ladle, torpedo, crucible, furnace), rim height and tilt, the metal and slag or dross, skimming per heat, reach and stroke needed from the machine position, slag pot position, tool type and changeover, and fume hood interfaces.
02
Decide the level of automation and the cycle time
A 2020 ICSOBA paper by GPS Global Solutions describes RIA's rail-guided aluminium furnace skimming machines: a base frame on driven wheels with an operator cabin for manual cleaning, an electrically driven carriage carrying the electrics and hydraulic unit that runs the skim boom into the furnace on rack and pinion, and a boom pivoted by a hydraulic cylinder, with quick-change skimming, cleaning and alloying tools. The standard machines are laser-guided and programmed with the furnace geometry, with cycle times of 8–12 minutes; the AI version uses air-cooled cameras whose images are processed in real time and passed to the PLC so dross is removed only where it sits and the tool is set at the right depth. The paper states automation can save up to 25% of in-furnace cycle time by shortening door-open periods. [4]
The same paper describes in-furnace dross processing, in which the skim blade squeezes hot dross against a cold plate on the furnace sill so liquid aluminium drains back, adding 1–2 minutes to the cycle; the author reports up to 2–3% more of the charge cast into product and dross generation and processing costs down by as much as 45%. These are the supplier's own figures. [4]
Befesa Aluminio's EP3165618B1 describes a crucible station in which an articulated robot moves interchangeable skimming, stirring and sampling tools in X, Y and Z, position detectors locate the crucible so it need not be placed accurately, a laser can measure the distance to the dross and the metal height, a dosing system adds reagents such as aluminium fluoride, and dross is thrown into a collecting box; it notes that existing crucible skimmers use a scissor-type double paddle suited to one crucible shape and size. [5]
Dynamic Concept and EPIQ Machinery's 2022 ICSOBA paper describes a custom battery-powered robot for skimming, stirring and dry cleaning of aluminium furnaces, designed because standard robots favour high speed and small payload while furnace tending needs slow motion with large payloads; it uses artificial vision and force control intended to avoid refractory breakage. [6]
State manual, semi-automatic or autonomous operation, guidance (laser, cameras, level measurement), tool force limits, cycle time target, interlocks with furnace doors and cranes, and the data the machine must report.
03
Column, boom, refractory paddle, robot arm and guidance sensors
Part
Role
Fix in the order
Column or base frame
Carries and slews the boom, or runs on rails. [2][4]
Mounting, travel, rails.
Boom and carriage
Extends into the vessel; pivots by hydraulic cylinder. [2][4]
Reach, stroke, drive.
Paddle, rake or blade
Pulls slag or dross over the lip; refractory-coated steel. [3][2]
Reach, skimming depth, cycle time and hydraulic pressure for a skimmer order
Reach and positioning accuracy have no published value in the reviewed sources, and the cycle time quoted is for one furnace design, so these rows depend on measurements from your own vessels. [4]
3 companies list this product among what they make. Company figures are quoted from each
company's own website; every card states where the relationship came from.
Fujian SOCMA Machinery Manufacture Co., Ltd.
Manufacturing site to be confirmed for the order
Lists a furnace tending machine for dross skimming and charging at aluminium smelting furnaces.
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.
The 8–12 minute cycles and dross-recovery figures above come from a supplier's own conference paper; ask each maker for plant references that confirm the cycle on vessels like yours. How we source and review
· Page last updated 13 October 2026
Buyer questions
Why is slag skimmed from hot metal after desulfurization?
The sulfur reacts with injected reagents and floats as slag, which is skimmed off before steelmaking. [1]
Why are skimmer paddles coated in refractory?
The steel thickness and refractory coating keep the paddle from melting into the hot metal. [3]
How long does an automated furnace skim take?
One supplier's laser-guided aluminium furnace skimmers run 8–12 minute cycles. [4]
Can a robot skim crucibles of different shapes?
One patented station uses a robot with crucible position detection and interchangeable tools for any crucible shape. [5]
Sources and what still needs a direct check
Sources checked 2026-10-11. AP-42 is a US government reference; the ICSOBA papers are written by equipment suppliers about their own machines; the patents describe designs, not current products. Values for your plant must come from the supplier offered.
