DD253951A1 - METHOD FOR SORTING COMBINED MIXTURES OF COMPONENTS OF DIFFERENT DENSITY AND WITH A WIDE CORROSPECTIVE - Google Patents

Abstract

The method is used in particular for the separation of koernigen mixtures whose sievability is problematic. After the process, the coarse mixture is fed to an air classifier, the remaining mixture is comminuted and fed to an air classifier. The number of individual work steps can be extended up to the required sorting effect.

Description

Field of application of the invention

The inventive solution relates to the sorting of granular mixtures in which the mechanical treatment makes it possible to use or reuse the individual components. The solution is thus applicable in the processing technology and in the secondary raw material economy.

Characteristic of the known technical solutions

For the separation of granular mixtures whose individual components have a different density, a variety of methods and devices are known.

For example, sorting stoves are known that work with the medium water and air. The disadvantage of these methods is the large water requirement, the low selectivity and the low flow rates.

Furthermore, sorting methods are known which separate granular mixtures with components of different densities with the aid of specifically heavy liquids or else with magnetic liquids. The processes have the disadvantage, in particular with a small particle size, that the mixture to be sorted is wetted by the liquids and thus contaminated, and the defect that the sorting effect is diminished by the influence of the surface tension of the liquid on small particles.

There are also known air separation methods which have been used successfully in the sorting of granular mixtures whose density differences are large. This air separation method adheres to the defect that they lead to complete sorting in the two components only if the grain size spectrum is narrowly limited.

Since granular mixtures often cover a wide range of grain sizes, the air classification method does not succeed in these cases.

Methods are also known which include both air sifting and sifting in combination. These devices are known, for example, in the processing of agricultural products and in the treatment of mineral raw materials.

A known method, DE-PS 2842259 C2, envisages, by successive sieving, the material to be sorted into sieve size classes to fan out and sort by air sifting each sieve size class separately. The same procedure also provides for sequential air classification to break down the material into different rates of descent and then separate the components by sieving.

This method has the disadvantage that the materials whose screening is difficult due to their material-specific characteristics, are difficult to separate into the individual components.

Object of the invention

The aim of the invention is to allow the dry sorting of granular mixtures whose individual components have a different specific density and a particle size spectrum of a certain width and whose sievability is problematic.

Explanation of the essence of the invention

It is the object of the invention to provide a method which enables the separation of granular mixtures of different densities as well as with a grain size of large width and difficult to be sieved.

According to the invention, the mixture to be sorted is supplied to a wind sifter to solve the problem, where initially the larger particles of the specific heavy component are separated from the rest of the mixture. The remaining mixture is comminuted to such an extent that the coarse grain fraction contained in it corresponds to the specific lighter component of the coarser remaining grain fraction of the specific heavier component. For comminution, such aggregates are suitable which allow a comminution of the materials to a defined grain size.

The further comminuted granulate mixture is in turn fed to an air classifier, where the now coarser grain fraction of the specific heavier component is separated from the remaining mixture. By further shredding and air-viewing operations, the degree of sorting can be arbitrarily improved.

The process achieves by comminution of each specific lighter component, a relatively fine granules of this component, which may be desirable in certain applications.

embodiment

It is necessary to sort a copper-plastic granulate mixture as a secondary raw material into the components copper and plastic in order to enable the reuse of both components.

This mixture was ground by grinding on a Schlagnasenmühle with sieve insert to a defined grain size of max.

1 mm crushed.

The mixture to be sorted is first fed to an air classifier. Here, with a wind speed of 4m / s, all copper components of size> 0.5mm are sorted out as sinking material. The remaining residual granulate, which is obtained as climbing material, is then comminuted to a particle size of <0.5 mm by means of a further defined comminution on a hammer mill with sieve insert.

The subsequent air classification takes place at a wind speed of 2.5 m / s. At this wind speed, the copper particles> 0.3 mm are sorted out as dew. On further stages of work is omitted due to the already achieved sorting grade and the achieved grain size.

The fact that only the specific lighter component is crushed, resulting in a very fine-grained granules for this component. This expands the range of possible uses for most secondary materials.

Claims (3)

1. A method for sorting granular mixtures of components of different density and with a broad grain spectrum, characterized in that the granular mixture to be separated is first fed to an air classifier, where the coarser grain fraction of specific heavier components is separated from the rest of the mixture and then the remaining Mixture is comminuted to the extent that the coarse grain fraction contained in it corresponds to the specific lighter component of the coarser remaining grain fraction of the specific heavier component to be fed again to an air classifier, where the now coarser grain fraction of specific heavier component is separated from the rest of the mixture. 2. The method according to claim 1, characterized in that the wind sifter to be set in each case wind speed is selected so that as little as possible get into the sinking of the specific lighter component, but get as many shares in the sinker from the specific heavier component. 3. The method according to claim 1 and 2, characterized in that the number of stages air classification and crushing in any number to improve the degree of sorting can be increased.