Why sinter and pellet handling combines the two hardest wear cases

Sinter and pellets arrive coarse and irregular. At the charging point the burden strikes with enough energy to crack a rigid face; a few metres downstream the same material slides along a wall and removes it steadily. These are not degrees of the same problem, they are two different failure modes that reward opposite properties — toughness at the strike, hardness along the slide.

Lining the whole asset for the worst zone is the usual response, and it is expensive twice over: you pay a premium across surfaces that never needed it, and the impact zone is still often under-specified because a single compromise construction satisfies neither demand fully.

Engineers often ask what temperature a ceramic will take. In a bonded construction that is rarely the binding constraint: the adhesive, the grout and the differential expansion between ceramic and steel reach their limits earlier. A specification that records only the ceramic's capability has documented the least critical element of the assembly.

Thermal cycling matters more than a single peak value. A surface that heats and cools through every campaign loads the joint repeatedly, and the failure appears at the joints and edges long before the ceramic face shows wear. Record the normal temperature, the upset temperature and how often the transition happens.

Steel plants are already organised around welding, and a hot-work permit is normally less of an obstacle than in a chemical or grain facility. That changes the retention calculus: weldable or mechanically keyed formats become realistic where a purely bonded installation would be exposed to the temperature and cycling described above.

Confirm the shell first. Welding needs sound steel of adequate thickness, and a shell already thinned by years of service may not accept the heat input. Measure before assuming the option is available.

Material temperature measured at the contact surface rather than in the process stream; lump size distribution including the largest credible piece; drop height and trajectory at the charging point; whether the shell moves or vibrates under load; and the realistic outage duration with the applicable hot-work rules.

Photographs of the failed area are worth more than any of these on their own. A dated image with an object for scale shows whether the loss is uniform thinning, localised cracking or a detachment — three findings that lead to three different specifications.

Establish a baseline at commissioning: dated photographs, marked reference locations and thickness readings wherever the shell allows access. After one campaign the comparison is factual, and the next specification rests on your own service data instead of a supplier's estimate.

Where no history exists for a construction in this duty, a controlled trial area is cheaper than a full reline. Instrument one zone, keep the rest as it is, and let the difference decide the next campaign.