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What one faces in the world nowadays is the stable trend in growing prices for raw materials reserve depletion of rich mineral resources. At the same time, the amount of hard-cleaning and mixed ores is increasing in the process of reserve development. Also, energy-saving production is becoming more and more important which is getting one of the main priorities in the mining field. All the factors mentioned lead us to search for alternative methods of benefication. This is why a new class called special technologies appears. Development of special technologies, as well as electronic methods of feedstock processing, is urged by the need to get new quality of technical and economic results of production which are impossible to achieve with the traditional technologies.
The traditional methods of lump benefication (magnetic, gravitation ones) refer to mechanic processing. These methods could be positioned as integral ones because they do not produce individual separation effect on each lump of the rock.
The sorters of the MLS model range are best positioned in comparison with their closer prototype the separator "Kammann Optosort".
The separators "Optosort" identify useful/dry lump of the rock based on analysis of the image of the material surface. The analysis is performed by the following operations: classification of color with expansion of the three-dimensional color RGB-space, morphological processing of the image of the objects, classification if the square, from, symmetry of separate lumps, ect.
But real effectiveness is only possible with technological means for water cleaning of the whole material of dust and other surface dirt. The presence of water cleaning in the technological process narrows the field of its application significantly because of geographic and climatic conditions.
Since analysis is performed for the surface but not for the volume of the separate lump, the accuracy of detection of the useful component in the lump is lower. This is the reason why the separators "Optosort" are mostly used for preliminary benefication. That is, they are placed at the entrance of the production string.
The MLS separators are free from these disadvantages since they do not require water resource and the analysis of the volume of the lump allows their use not only as preliminary benefication stage but also as finishing facility.
Operations
The control of the useful component in MLS is performed by defining physical properties of the feed material. Depending on how contract the properties of the useful component are against the enclosing rock, there are two basic arrangements of the equipment:
- for feedstock with well-distinguished properties
- for feedstock with low distinguished properties
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MLS is a mini-plant performing 7 main and 5 additional operation. As
per
Technical Requirement: "TY Y 29.5-13449523:2007 Module of Lamp
Separation of mineral feedstock and technogenic wastes". The process
flowsheet of the lump separation looks as follows (pic.1).
Main Operations:
1-receiving feedstock; 2-dosing: 3-laying; 4-transporting; 5
energetic effect; 6-control, fixation and analysis of useful
properties;
7-sorting.
Additional operations:
I-providing with compressed air; II-aspiration of dust-forming points;
III-boosting ventilation; IV-preparing parameters of feedstock, belt;
V-dispatching.
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The operation in the given sheet are know and quite informative.
Additional information is required for the operation: #5 - energetic
effect; #6 - control, fixation and analysis of useful
properties
Operation #5. Energetic effect is applied for feedstock with low distinction properties and is designed for activation of useful properties of the minerals and other indirect parameters correlated
with the useful properties. The idea of the operation is best at the example where a microwave resource is used as the activator. The effect of the high-frequency field leads to different hearting of the useful component and the enclosing rock. Thus, further analysis is done for the indirect parameter - temperature which is correlated with the concentration of the useful component in the lump. The level and the
manner of the minerals account for identification of the "useful/dry" lump.
Please see below the variants of images of
ore samples in the visible light (on the left) and infra-red radiation
(on the right).
Variant 1. Manganese ore, Ghana, Africa.
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Sample 1 - Mn=32,1%, Fe=0,8%;
Sample 2 - Mn=32,4%, Fe=8,1%;
Sample 3 - Mn=26,3%, Fe=13,5%;
Problem: highly ferriferous manganese ores Fe>10% limit
volumes of feedstock appropriate for production of ferroalloys with
permissible ratio Mn:Fe=6:1. Due to low contrast of the separated
materials for density C~1,15 (Mn: pyrolusite, psilomelane, vernadite;
Fe: hematite, goethite, magnetic) complex gravitational and magnetic
concentration technologies are traditionally applied.
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Variant 2. Low grade magnetite ores of Kaz deposit, Russia.
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Sample 1 - content of sulphur S1=1,7%.
Sample 2,3 - higher content of pyrite, correspondingly: S2=5,3%,
S3=8,8%.
Problem: high content of sulphur in iron ores is a negative
factor in production of ferrous metals. The contrast for density in
the
given group of ores is ~ 1. The selective recovery of lumps
containing pyrite is impossible by traditional methods of mechanic
processing. On the other hand, with selective recovery of lumps with
high content of pyrite there may be recovered minerals containing
gold,
which accompany pyrite.
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The special feature of the method is that the feedstock does not need
cleaning off dust and dirt since it is not the surface but the
volume of the lump that is analyzed.
Operation #6. Control, fixation and analysis of physical
properties of feedstock is done by means of modern control tools and
special information technologies and eventually represents the
software
product which is 90% of the cost of the MLS separator.
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How it works
For how it works please see the following three dimensional scheme:
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