Abstract: At least a percentage of iron ore pellets and the like for use in a direct reduction process for the production of sponge iron are coated with a thin porous coating of Portland cement to counteract tendency to aggregate. This is accomplished by method and apparatus that mixes water and cement powder at the point of delivery in a manner such that no pumps are subjected to a wet cement slurry. The slurry is mixed and maintained in suspension by air agitation in a bin and then flowed through a bin discharge pipe and sprayed therefrom onto a passing layer of pellets in a controlled manner by regulated air injection into the discharage pipe.

Abstract: Improved process and apparatus for the reduction of iron oxides employing a solid reducing agent. Particulate iron oxides are mixed with particles of the reducing agent and are subjected to high temperatures within a vessel made of refractory material which is externally heated in a furnace. The problem and drawbacks that have been found in the past, such as the fracture and high costs of the refractory vessels, are solved by means of the present invention which comprises laying a sheet made of tinplate or of other suitable material, between the vessel and solids to prevent them from sticking to the vessel because of the high temperature, thus providing an economic and advantageous process. In one of its embodiments, this process is particularly suitable for the production of high purity iron, that is with a low content of gangue and carbon. This high purity iron, once converted to powder with adequate particle size, has a number of diverse applications in industry.

Abstract: Sponge iron is carburized in the cooling zone of a vertical shaft iron ore reduction reactor by causing a carbon-containing gas to circulate in a closed loop including the cooling zone of the reactor and an external conduit containing a quench cooler and a pump. Improved control of the carburization of the sponge iron is achieved by measuring the specific gravity of the circulating gas and using the measured specific gravity value as a control variable effectively to regulate the flow of make-up carbon-containing gas to the cooling loop.