Serial classification

A new highly efficient process for sorting particles by shape

Definition of the particle dimensions

Black box scheme of “double serial classification”

Forces at the single particle and the resulting particle movement

Possible aperture geometries for use in “serial classification”

Single- and multi-particle model of “double serial classification“

Description of an ideal sorting by particle shape cubicity

Separation criterion distribution model for determining the ideal particle shape characteristic values

Example of a narrowly distributed particle shape number distribution (photooptical measurement)

Results of “double serial classification” of dispersed bulk solids (1/25 mm)

$Diagram of the cubic (a) and non-cubic fraction (b) of a sorted gravel fraction 4/8 mm$

Diagram of the cubic (a) and non-cubic fraction (b) of a sorted gravel fraction 4/8 mm

$Results of the sorting of a 4/8-mm gravel fraction by cubicity$

Results of the sorting of a 4/8-mm gravel fraction by cubicity

Summary: The macroshape of particles in material mixes or fractions has considerable influence on a wide range of product properties. For this reason, in numerous industries there are potential applications for particle shape sorting methods in order to improve product properties. One of these potential applications is the production of high-grade chippings, with cubic particles complying with the technical specifications (e.g. TL Gestein-STB 04 in Germany). At the Institute of Mineral Processing Machines at Freiberg University of Mining and Technology a sorting method was developed with which it is possible to sort particles by shape.

1 Motivation for particle shape sorting

In many production processes the particle shape has a significant influence on the quality of the products produced. Many material properties, for example conveying and flow behaviour, permeability or the reactivity, depend on the particle shape [2, 4, 7, 9]. For instance, in material recycling, with the various process stages (comminution, compaction), mixes of various material groups are formed, in which the individual material groups differ significantly in their particle shape. This is the case, for example, in the shredding of various types of waste,...

Issue 05/2023 Energy-efficient ejection module

Optimised XRT ore sorting solution for fine particles

TOMRA Mining has launched a new ejection module for its proven COM Tertiary XRT sorter specifically developed for sorting small particle sizes. The COM Tertiary XRT Fines sorter, featuring the new...

Issue 01-02/2021 Make one out of two

New freefall sorting installation for sorting waste materials

C?onstruction waste is produced when civil engineering structures are demolished and during the deconstruction of buildings. Even if a building is selectively deconstructed, mixes of building...

Issue 09/2012

Increased potential of recyclable materials

Optimization of the processing of NF metal concentrates from waste incineration ashes

1?Introduction In standard processes for processing WI bottom ashes, following coarse primary classification, usually at cut-points between 40-100 mm, magnetic separators are used to remove any...

Issue 01-02/2013

Universally applicable

Mineral sorting with multiple sensing features

Sensor-based sorting systems available on the market today must demonstrate sufficient flexibility to permit their application in a wide range of conditions. Typical challenges for the sorting systems...

Issue 05/2021 Tests on a freefall sorter

Sensor-based sorting of mineral waste and raw materials

1? Sorting systems in the recycling economy Concomitant with the rapid development of computer technology and significant advances in sensor engineering, the development of sensor-supported sorting...