The production process of reduced iron powder for powder metallurgy is to use carbon, that is, coke powder, as the reducing agent for primary reduction. What is produced is a semi-product sponge iron, which is then crushed and then reduced for a second time, using hydrogen. Reduction is performed as a reducing atmosphere. According to the analysis of the redox atmosphere phase diagram, the original raw material used for reducing iron powder is iron oxide scale, which exists in the state of ferric oxide. Simply using hydrogen for reduction is difficult, costly and low-efficiency. Therefore, a tunnel kiln is used to reduce the iron powder with carbon. The agent reduction efficiency is high and the cost is low, so carbon is used as the reducing agent for deoxidation treatment in the primary reduction;

The purpose of the secondary reduction is to remove impurity elements, including carbon and oxygen, and at the same time eliminate particle hardening , so hydrogen is used as the reducing atmosphere;

So the question you asked is the product produced by the first reduction and the second reduction in the production of reduced iron powder;

The so-called carbon Reduced iron powder is a one-time reduction, commonly known as primary powder. It contains low iron, high carbon and oxygen, and the particles are hardened. It cannot be used for product pressing and is generally only used for reactions such as chemical industry;

The so-called hydrogen reduction Iron powder is a secondary reduction, commonly known as secondary powder. It contains high iron purity, low impurity content, good product plasticity, and is easy to press. It is used for powder metallurgy pressing. Of course, the sales price is also high due to multiple production processes.