Mechanical mixing of desulfurizing reagent in a hot-metal ladle
A KR desulfurization reactor uses a submerged rotating impeller to mix hot metal with the desulfurizing reagent. The reaction unit is the treatment ladle and its mechanical stirring arrangement. Its vessel geometry, filling level and impeller position must be defined together.
Mechanically stirred KR hot-metal desulfurization reaction units: the treatment ladle and submerged impeller arrangement. Page 152 covers reagent-lance injection stations and explicitly excludes KR mechanical stirring. Molten-steel ladles (990), foundry magnesium-treatment ladles (1000), gas-injection systems, dephosphorization converters and complete integrated slag-treatment plants are outside this KR reaction-unit type.
CNFX editorial research · Sources checked October 18, 2026 · 3 sources
Combine the treatment ladle with the specified submerged impeller
Nippon Steel Engineering defines KR as a mechanical mixer-type hot-metal desulfurization facility, using immersion and rotation of an impeller to mix the hot metal and reagent. This differs from delivering reagent through a gas-injection lance. [1]
Nippon Steel’s technical report describes KR using ladles as reaction vessels with a molten-metal stirring mechanism. Its process discussion separates hot-metal desulfurization from dephosphorization because their required reaction conditions differ. A generic refining vessel description therefore does not establish the duty or configuration of the ordered KR unit. [2]
The ISIJ impeller study compares different blade structures in a defined vessel, with model assumptions excluding chemical-reaction and mass-transfer effects. Its mixing results support reviewing impeller geometry and vessel conditions together; they do not establish a delivered sulfur-removal guarantee. [3]
02
Keep the facility speed separate from a model-specific recommendation
Nippon Steel Engineering’s KR product overview describes an impeller speed of approximately 120 rpm. The ISIJ study instead recommends 80 rpm within its investigated arrangement. Its parameter table specifies a 4 m bath-mouth diameter, 3.3 m molten-iron surface height and 1.3 m impeller immersion depth, with rotation speeds studied from 60 to 90 rpm. These are separate source contexts, not interchangeable ratings for an unidentified reactor. [1][3]
The paper discusses overflow risk at its higher investigated speed and selects its recommendation for the studied configuration. Confirm the operating envelope against the ordered ladle, bath level, freeboard, impeller profile and immersion. The source values do not establish a universal minimum or maximum speed, nor a sulfur-removal percentage for another reactor. [3]
03
Provide the ladle drawing and impeller operating envelope
Paste it into your enquiry below or into an email to a maker, then replace every bracket.
Duty: [hot-metal desulfurization route; incoming metal and required treatment]
Vessel: [treatment-ladle drawing; lining; bath level/freeboard; handling interfaces]
Stirrer: [impeller profile and material; immersion; shaft and drive; withdrawal clearance]
Operation: [manufacturer-approved speed envelope; reagent addition; sampling and slag removal]
Plant interfaces: [hood; ladle transport; skimming; access and maintenance]
Acceptance: [mechanical checks; commissioning trial; process guarantee with stated inlet conditions]
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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 18 October 2026
Buyer questions
Is a KR reaction unit the same as a reagent-lance injection station?
Nippon Steel Engineering describes KR as submerged-impeller mechanical mixing. Nippon Steel’s process report treats KR and flux injection as separate hot-metal desulfurization routes. [1][2]
Does the impeller study supply a universal reactor speed rating?
The study concerns its defined vessel, impeller structures and model assumptions. The facility overview describes a different context. Obtain the operating envelope for the ordered geometry and bath conditions. [3][1]
Sources and evidence scope
Sources checked 2026-10-18. Nippon Steel Engineering describes the KR facility, Nippon Steel’s technical report places the ladle-based route within steel refining, and the ISIJ paper studies impeller mixing under stated assumptions. Model results and product-overview values are kept separate.
