Processing plant

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View of the screening machine in a rock processing plant.

A processing plant is used to process raw materials such as water , coal , ore and natural stone in order to change their material composition and properties in such a way that they can be used in industry. For example, hard coal or iron ore are separated from undesired, co-extracted components.

The processing step is between the extraction or extraction of the raw material and its further processing. In order to reduce transport costs, the volume to be transported is greatly reduced by processing close to the mining areas.

application areas

water

Water treatment plants are process engineering facilities that adapt water to the specific requirements of the consumer / user.

ore

Former ore processing in the San Fernando mine in Herdorf

Ores contain large proportions (up to 70%) of so-called gangue , that is, dead rock such as silica , clay , limestone . There are also undesirable accompanying elements and impurities that cause metallurgical problems during smelting and must be disposed of in the form of hazardous waste.

The processing of the ores includes the following steps:

  1. Crushing , the crushing of the mined ore up to a required particle size takes place in crushers.
  2. Grinding takes place in mills. In wet mechanical processes, the ground ore is turned into a pumpable suspension.
  3. Classification , by classifying (sieving) the ores that have already been crushed are divided into different grain classes.
  4. Floating , in the physico-chemical process, substances dispersed or suspended in the water are transported to the surface of the water by adhering gas bubbles and skimmed off there. The ore concentrate is the product.
  5. Thickening , due to the action of gravity, the solids are concentrated in radial, paste or high-performance thickeners
  6. Filtration , the concentrate is put into filters, e.g. B. vacuum belt filters, cleaned and drained.
  7. Drying, the pure concentrate is dried, mostly in rotary ovens.
  8. Storage, depending on the further use, the dried concentrate is stored as a powder or as pellets .

coal

Raw coal is by promoting surrounding rock as sandstone and clay slate (as well as of mineral inclusions oil shale , fire shale , pyrite , calcite , siderite interspersed etc.), not usable in this state and must be treated.

Natural stone, gravel and sand

simple separation system for the extraction of gravel

The raw materials gravel and sand as well as natural stones (such as lime and gypsum) occur naturally contaminated or in undesired composition ratios and must therefore be processed. Further use, for example in concrete production, requires the aggregate to be divided into different fraction groups.

Procedure

  1. The materials are crushed in crushers .
  2. In flow channels , Sinkscheidern or joining machines, the components due to the different specific weight separated (are coal washing ).
  3. In screening machines a classification by size.
  4. In hydrocyclones , gravity is separated with the addition of flotation reagents in the flotation .

Third-party products can also be added in the course of processing. In ore processing, for example, secondary raw materials such as metal-containing filter dust or smelter circulation products are combined with the primary raw materials. In this way, for example, metal-containing steelworks dust is reintegrated into the blast furnace process.

Complex procedural measures are necessary for the variety of secondary raw materials in the waste and scrap sector. For an industrialized country, the existing, circulating, secondary metal-containing raw material is extremely important - accordingly, the shredding (e.g. the shredding of old cars), sorting and return (recycling of components such as plastic, copper-containing electrical cables, window pane glass and lead from old batteries) is special Issue of processing.

literature

  • Specialized committee for ore processing of the Society of German Metalworks and Miners eV (Ed.): Ore processing plants in West Germany. Springer Verlag, Heidelberg 1955.
  • Georg Maybaum, Petra Mieth, Wolfgang Oltmanns, Rainer Vahland: Process engineering and construction operations in foundation engineering and special civil engineering. 2nd edition, Vieweg + Teubner Verlag, Wiesbaden 2011, ISBN 978-3-8348-1416-6 .

Web links

Remarks

  1. ↑ As a brand shale refers mixed with thin carbon layers shales . The coal and the shale can also appear in alternating layers. Fire slate has a high ash content. (Source: Walter Bischoff , Heinz Bramann, Westfälische Berggewerkschaftskasse Bochum: Das kleine Bergbaulexikon .)