Beneficiation of ferrous metal ores

Methods of enrichment of ferrous metal ores can be conditionally divided into several main stages.

At the first stage, the gross extraction of the rock mass of ferrous metal ores is carried out – this is the so-called input product.

The second stage includes crushing and grinding processes in order to improve the enrichment characteristics and “extractability” of useful components.

Then radiometric separation is used for preliminary enrichment of the lump product, therefore, two products are formed - a rich lump product and a poor one. The rich lump product is sent to the metallurgical stage. The obtained ore product is crushed and sent to the flotation or magnetic flotation enrichment process at the enrichment plant. The ratio of the number of free (open) particles to their total number in the enrichment of ferrous metal ores is called the degree of disclosure. After carrying out flotation enrichment processes, enriched (concentrate) and depleted (tailings) products are obtained. Scarce materials (starch, soda, oils, sulfite liquor stillage, crude sulfate soap, etc.) are used as flotation reagents at modern flotation plants. The resulting concentrate is sent to the metallurgical plant for subsequent casting of iron, etc.

Flotation is the most common, but not the only method for obtaining black concentrates.

Magnetic methods are widely used at the primary stages of enrichment. Magnetic methods are usually preparatory to flotation processes, but are sometimes used as full-fledged methods for obtaining concentrates. Magnetic enrichment is based on various characteristics of ore elements in a magnetic field, which allows separating the magnetic (iron) component of the ore from the non-magnetic (gangland), of course, with a certain degree of error. Therefore, the non-magnetic component should not be considered as a rock that does not contain valuable components. Separating forces arise in the magnetic field, which are used to separate the components. Machines that operate on this principle operate with high energy and water consumption, and with minimal labor costs, providing high productivity. This method is mainly used to enrich magnetite ores. The basic diagram of a magnetic separator is shown in the figure below.

There are also enrichment methods based on differences in the gravitational properties of the ore components. These methods are called gravity enrichment methods. The process of gravity enrichment can occur both in air and in liquid.

The most difficult to enrich are ores of quasi-colloidal and colloidal structure. Currently, ores of this type are either not mined or are lost in waste. This is due to the fact that in the currently operating grinding machines for this type of ore, the opening of intergrowths does not occur. Thus, one of the main requirements for the enriched product is the complete opening of the ore intergrowths.