In Ukraine located about 20% world reserves of iron ore — 80 industrial fields. Domestic mining sector consists of 26 companies. These companies produce the whole range of iron ore resources: an ore, a concentrate, ovoids and agglomerates. Ukraine is the sixth largest iron ore producer.
Kryvbas is one of the largest iron ore basin in the world. It includes a series of fields in length over 100 km through Dnipropetrovsk, Kirovohrad and Mykolayiv region. Iron ore with high metal content occur in Kremenchug (Poltava region) and Belozersk (Zaporizhia region) iron ore districts.
In the above areas there are six major mining and processing enterprises. They form the majority in Ukrainian production of concentrate, ovoids and agglomerate:
- Ferrexpo Poltava GOK;
- Northern Iron Ore Enrichment Works;
- Central Iron Ore Enrichment Works;
- Yuzhny Mining and Enrichment Plant;
- ArcelorMittal Kryvyi Rih;
- Ingulets Iron Ore Enrichment Works;
Ore milling happens in drum mills and steel grinding balls used as milling media. Each of the enterprises has its own specificity in grinding technology, depending on the physical chemical properties of the enriched ores in this enterprise.
All enterprises use a classic scheme of raw material grinding and it consists of 3 steps. We consider each of them in more detail:
The first grinding stage. Two drum mills used for grinding raw materials in the first grinding stage; they work in the waterfall operation mode. Mainly, mills use 100mm — 120mm grinding balls. In some cases, mills use the steel rods (it is round billet equal to length of the inner drum mill).
The second grinding stage. One drum mill involve in the second grinding stage. Mills use 60mm — 40mm grinding balls as grinding media. Mills operate in cascade operation mode or mixed operation mode. Thus, the ore ground due to the abrasive action of crushing and grinding media
The third grinding stage. One drum mill involve in the third grinding stage. Mills operate in cascade operation mode or mixed operation mode. Mills use 40 mm — 25mm grinding balls.
Some enterprises include «regrind» step in their grinding scheme. This step is implemented in order to improve the quality of the concentrate by re-grinding industrial product obtained due to the third grinding stage. The regrinding mills often use 30mm — 17mm steel grinding balls.
Specialists of «Energosteel» company constantly keep in touch with the technical experts of mining & processing enterprises mentioned above. On our specialists’ initiative, each of the enterprises carried out industrial tests. These industrial tests have changed the terms of the grinding process, namely:
- A diameter of the grinding balls in mill operation,
- Use of grinding balls with different groups of hardness,
- Reducing load mills by grinding balls,
- Replacing other grinding media on the grinding balls, etc.
The main aim of industrial tests was to reduce costs of one ton iron ore production due to changes grinding media physical and chemical properties without loss the quality and the quantity of concentrate.
As a result of industrial tests, mining & processing enterprises continue use the steel grinding balls of «Energosteel» production in their ore grinding technology. Thus, currently, «Energosteel» grinding balls used on the largest Ukrainian mining & processing enterprises in the iron ore production.
Technical specialists of «Energosteel» company constantly monitor the quality of grinding balls in the conditions of enterprises work and regularly introduce new solutions in the field of grinding minerals.