Sinter plant

A sinter plant agglomerates iron-ore fines, coke breeze, fluxes, return fines, and other materials into porous sinter suitable for blast furnace burden. It turns fine materials that would restrict furnace gas flow into a stronger, permeable feed.

The mixture is granulated with water, charged onto a moving grate or strand, ignited at the top, and drawn downward by suction. The flame front moves through the bed, partially melting and bonding the particles. The fired sinter cake is then crushed, screened, cooled, and returned or sent to the blast furnace depending on size.

Off-gas and dust behaviour

Sintering produces a large, dusty off-gas stream with iron oxide, alkalis, chlorides, sulphur compounds, heavy metals, dioxins depending on feed and controls, and fine carbonaceous material. The windboxes, ducts, ESPs, baghouses, fans, and hoppers handle abrasive and sometimes sticky dust.

Deposits form where temperature drops, gas velocity changes, or sticky salts condense. Return fines and feed variability affect permeability, strand speed, fuel rate, and off-gas loading. Poor bed permeability can increase suction demand and disturb combustion.

Failure modes and controls

Common operating problems include strand leakage, windbox build-up, duct plugging, fan erosion, ESP performance loss, baghouse blinding, cooler dust, and unstable sinter quality. Environmental controls may include ESPs, baghouses, scrubbers, activated carbon injection, desulphurisation, and selective catalytic reduction depending on local requirements.

Operators track strand speed, bed height, ignition temperature, suction, burn-through point, return fines, basicity, tumbler strength, and emissions. Cleaning systems must keep dust moving without causing re-entrainment or excessive equipment wear.

Acoustic cleaning context

Sonic horns are used in sinter-plant off-gas equipment where dry dust builds on ESP internals, duct ledges, baghouse hoppers, or bins. They are useful for preventive cleaning of friable deposits. They are less effective against sticky condensed salts or hard sintered accretions, which need process-temperature control, material control, or outage cleaning.

Operating and emissions context

A sinter plant blends fine iron ore, fluxes, return fines, coke breeze, and recycled residues, then burns the bed on a moving strand to form porous sinter for the blast furnace. Operators track bed permeability, ignition temperature, strand speed, suction pressure, return fines rate, basicity, fuel rate, and product strength. Poor bed control increases fines, raises fuel use, and changes the dust and fume load sent to gas cleaning.

Environmental control is central because sinter off-gas can contain particulate, sulphur oxides, nitrogen oxides, heavy metals, acid gases, and organic compounds depending on feed. Gas paths include windboxes, main ducts, ESPs, bag filters, scrubbers, fans, and stacks. Maintenance concerns include windbox leakage, duct build-up, fan erosion, ESP hopper flow, and sticky deposits from chlorides or alkalis. Acoustic cleaning may be useful on dry dust build-up in ducts, hoppers, and collection equipment, but not on the hot sinter bed or fused deposits in the process itself.

Related terms

• Electrostatic precipitator
• Baghouse
• Sonic horn