Integrated steel mill

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An integrated smelting works is a combination of several production stages at one location in order to manufacture steel products from the raw materials . Usually the work consists of:

  1. Blast furnaces that make raw iron from ore ,
  2. mostly a coking plant to produce the metallurgical coke required in the blast furnace ,
  3. a steel mill that produces fresh steel from pig iron ,
  4. a foundry to produce semi-finished products from the liquid steel, and
  5. a rolling mill that produces the finished product from the semi-finished product,
  6. as well as ancillary systems such as power plants , systems for process gas generation , utilization of by-products (especially slag ) and maintenance companies.

Use means of an integrated steel mill are ore , coke and limestone . The end products of an integrated steelworks are flat steel , steel profiles and slabs .

Historical development

Many of the iron and steel works of the coal and steel industry in the Saar and Ruhr areas (e.g. Krupp in Essen, the August-Thyssen-Hütte, the Bochumer Verein , Phoenix in Dortmund) represent historically grown, integrated ironworks, some of them even mined coal or ore at the smelter site - i.e. they were even more vertically integrated than today's plants.

These smelting works started the vertical and horizontal integration mostly from steel production with puddle and crucible furnaces, to which a foundry and forge were assigned. The next step in the forward integration consisted of the connection of rolling mills , then turning shops and mechanical workshops to mechanical engineering. The backward integration consisted in the construction of blast furnaces, which agglomerating plants, coking plants and collieries / mines were connected upstream and pig iron mixers.

In Lorraine and in the Peine-Salzgitter area, iron ore was often mined directly at the site of the smelter, and hard coal in the Ruhr area. In the course of increasing efficiency, by-products such as coke oven and blast furnace gas were used to generate heat and later electricity, i.e. all parts of the plant were operated in an energy network. The smelter coking plants were mostly given up in favor of large coking plants close to the collieries, which had more space for the by-product plants. The puddle and crucible steel process was replaced in the 19th century by the Bessemer / Thomasstahl process, then the Siemens-Martin process and at the beginning of the 20th century by electrical steel and finally the LD process in the middle of the 20th century. The extraction of raw materials at the smelter site was mostly given up in the 1960s due to the exhaustion of stocks or the lack of profitability at all locations in Germany.

Situation today

Practically all steelworks that have been newly established in the industrialized countries since 1985 are integrated steelworks in order to guarantee the most efficient production possible and to survive in the tough international competition of steel production. In Korea and Japan in particular, there are plants that are located directly next to steel processing companies.

The integrated smelters are usually located in such a way that they can be supplied inexpensively with the raw materials that are shipped by ship. That is why newly built plants usually have efficient ports.

Since the integrated works have a very large capital requirement, there is an alternative concept for steel production at one location with so-called mini mills ( electric steelworks ).

Examples

See also