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Recycling of industrial wastes

Processing of dust fractions of aluminium skimmings and salt slags

Description of the technological line:

The process equipment operated by KVS Ekodivize, a.s. Horní Benešov applies the following procedure to process dust fractions of aluminium skimmings and salt slags.

Skimmings are transported in large-capacity bags onto the premises of the plant and stored in a closed indoor store. From there the bags are transported to the technological line proper. The treatment of the input material consists in catalytic decomposition at higher temperature and pressure by water in stirred heated multi-stage reactors. Gaseous products that are generated and contain hydrogen, methane and ammonia are drawn off into a combustion chamber and the heat generated from this process is used for the additional heating of the decomposition process or for the vaporisation of water from brines. Brine is obtained from the separation of the solid and liquid phases of slurry produced from decomposition reactors. Further, the solid phase is washed multiple times, thereby getting rid of residual water-soluble substances to obtain the required value. The decomposition of the input material and additional washing result in an inert product free from dangerous properties containing aluminium oxides, aluminium hydroxides, aluminium oxyhydroxides and oxides of accompanying elements (silicon, magnesium, calcium, iron). The inert material is mixed with binding material and additional raw materials and it is pelletised. The pellets are dried up to the required minimum moisture content, dust fractions are selected out and the resultant product is despatched. The liquid phase containing water-soluble salts is evaporated. Cooling of the waste vapour that is being exhausted is used to obtain water for washing, and the final wash water is employed for decomposition water into the reactors. Thickened brine solutions are subjected to crystallisation. Crystals that have formed are dried up, mixed with necessary components and they result in cover or refining salts used in aluminium metallurgy.

The technology focuses on utilising all waste substances in order that it is waste-free. The solid phase is utilised for an ALCATEN product, which is used as a replacement of fluorspar for iron metallurgy. The liquid phase is utilised to obtain a secondary raw material – ECOSAL products, which are used in aluminium metallurgy. The gaseous phase is burnt and used to generate heat.

KVS EKODIVIZE a. s. has all the legislative prerequisites for operating the technology concerned, imposed on it by the laws of the Czech Republic, including a licence to import hazardous wastes of the given category from abroad.


Technical information

We process dust fractions of Al skimmings produced in aluminium works.

1. Origin:

Industrial waste from the processing of aluminium.

2. Composition:

Metallic Al 0-10%
Al2O3 at least 20%
NaCl + KCl 10-60%
SiO2 5% at most
Fe2O3 + MgO 10% at most
Cu 0.5% at most
As, Sb 0.2% at most
Cd 0.1% at most
Pb, Zn 0.2% at most
Co 0.1% at most
Ca 10% at most
organic substances 0.1% at most
H2O 0.2% at most

3. Grain size:

0-0.2 mm 90%
0.2-2 mm 10%
over 2 mm 0%

4. Packing:

BIG BAG with a bottom outlet for ca. 1300 kg

5. Transport:


6. Classification:

Company standard: RST - 02 - 01<
Waste designation: Wastes from aluminium thermal metallurgy
Waste type code: 10 03 xx

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