MDMW Magnesite01

132 Mineral Processing Technology (MPT 2007)
Magnesite Processing in Turkey

D. Renda
Mining Engineer, Ph.D, Member of Steering Committee of Turkish Miners Association, Istanbul, Turkey.
Deputy Chairman of the Board (retired) of Magnesit AS, Istanbul, Turkey.
ABSTRACT: The cryrptocrystalline magnesite deposits in Turkey are associated with ultrabasic weathering
rocks-serpentine and located in the Midle, Southern and Eastern Anatolia.
In this paper, the processing methods applications: hand and photometric sorting, the heavy-medium and high
intensity permanent magnetic separation are elaborated.
All of these methods are currently applied in magnesite concentration plants belong to mining companies.
1. INTRODUCTION The magnesite which has 50–300 mm grain sizes,

to which the pre-sorting process has been applied,
Magnesite ore is generally with high iron content which has been crushed and screened is cleansed
and in crystalline formation throughout Europe. from its serpentine and other impurities by the use
However in Turkey, it is found with non-iron con- of light pick-hammers, whose weight does not
tent, white colored, in cryptocrystalline formation exceed 1 kg.
and amorphous. The fact that its color, its color’s For the hand picking, the ore-loss from
light diffraction, its specific gravity and its deposits is stored in the tailing area in significant
magnetic susceptibility are different from the host rates like 60–70% in gangue or stock work type
rock serpentine facilitates its distinction from the formations, in which selective production is
silica impurity holding serpentine. made. Therefore the ore benefit is at most
This character difference of magnesite and of 30–40%. Because the grains smaller than the
serpentine provides great facility concerning grasp of the palm of a man, which are smaller
either hand picking or other automatic ore sorting; than 50 mm, goes directly to the tailing area.
and prevents both humans and machines to Qualitative and quantitative deviations due to
commit picking-selecting and cleaning mistakes. human mistakes and omissions are always to be
expected as far as hand picking is concerned.
Yet there are criteria to be paid attention in
order to realize a non-mistake ore processing.
These are: 3. MAGNETIC ORE-SORTING
The selection of exact grain size and Perfect The run-of-mine magnesite grains, which are
Washing processes. crushed down to 5–300 mm grain sizes, screened
For this reason, there should be duly working and washed, shall provide a higher sorting
crushing-screening and washing plants in a efficiency through magnetic ore sorting method,
mining enterprise. which is to be applied after magnetic pre-sorting.
In order to reach the desired qualitative and The magnesite grains, by having fed with
quantitative results both in hand picking and in 40–50 t/h on the drum or belt magnetic separators
automatic ore sorting, a pre-sorting process under dry type 15–25 Tesla magnetic field
should be applied to the excavated run-of-mine intensity, the non-magnetic magnesite and
before final sorting process. magnetic serpentine are separated from one
2. HAND PICKING another. This separation is realized due to the fact
that the magnetic sensitivity of the serpentine is
133 Mineral Processing Technology (MPT 2007)
far more than magnesite. The serpentine recovery serpentines from magnesite concentration during
is over 75% with Magnetic ore-separator. How- the heavy medium plants’ work.
ever the separated non-magnetic material is nut The mineral, which provides the heavy
100% magnesite; 5–10% of it may be serpentine. medium to be selected according to the separation
These serpentines should be eliminated and curve is usually Ferro silicon, the bulk density of
disposed of. The serpentines which are attached to which is 2,70 g/cm3.
the magnesite should be cleansed by a pick
Ferro silicon may easily be recovered from
hammer. The magnetic ore sorting application on
the heavy medium drain water by magnetic
magnesit has started with superconductive ore-
separators, due to its magnetic feature.
sorters. This separation is actually continuing with
RE-Permanent magnetic separators and very fine In the hydro-cyclone, which operates in
separation results are taken. heavy medium liquid of 2,70 g/cm3 the magnesite
of 2,35–2,45 g/cm3 of density easily floats and
this floating material may be recovered from over
4. HEAVY MEDIUM SEPARATION the cyclone. The serpentine of 3,70 g/cm3 shall be
the sinking material and thus discarded.
The pre-sorted, washed, crushed and selected
magnesite of which the size is 5–40 mm is fed
with dense medium cyclone for the Sink and 5. PHOTOMETRIC ORE-SORTING
Float Process. Here, in order the separation of
serpentine and magnesite to be due, the washing This method is based on the colour difference
speed and washing period on the washing drum is between amorphous magnesite and the green to
important, besides the grain size of the fed dark green coloured altered serpentines as the
material. Forasmuch as the magnesite reserve for country rock. Photometric sorting has become
every mineral deposit has a specific separation very popular in magnesite beneficiation due to
curve and separation character, and making of the high selectivity and low maintenance cost.
optimum separation takes place as a result of The pre sorted magnesite is fed on belt
many experiments to be realized in lab. The conveyor with a slow run. The photometric ore
specific gravity of the magnesite in Turkey differs sorter has laser rays to the material and scanned
from 2,35–2,45 g/cm3. The host rock (mullock) the running material and each particle reflected
serpentine’s specific gravity is approximately oneself back to ore sorter.
3,70 g/cm3. This difference shall cause to no The measurement of reflectivity from each
difficulties in the separation of the magnesit from particle is evaluated in the compurized mechanism
well washed serpentine, the pore spaces of which and selected material is compressed air actuated
is full of water. The optimum separation curve, pneumatic force lifts upwards from the belt
which is to be deduced through heavy medium
conveyor.
density experiments and washing period
experiments held in the lab, takes its last The big disadvantage for this process is the
condition according to the impurities of the uneven distribution grade and the mixing the light
magnesite. coloureted serpentine in the concentrate too.
Although the specific gravities of the This uneven distribution grade makes
serpentine and the magnesite are so different from difficulty in quality control at the concentrate. To
one another, the optimum washing period and solve this problem secondary hand sorting for the
heavy medium density which are to be fixed in coloured particles must be followed.
the lab, because of the variations of the pores’
structures, makes the wished separation quality
6. FLOTATION
difficult to achieve and additionally compels to
the hand picking process in the separation of
Magnesite Processing in Turkey 134
The flotation that is to be applied in order to win Turkey’s magnesite mineral deposits, which
and to regenerate the fine-grain magnesite, which are an industrial mineral, have become more
is of 2–3 mm of grain size, should be utilized as important after the year 1960.
some kind of mineral processing method. From then on, many companies that have
The material of this size is prepared for its been established basing upon the found mineral
using with no cost in the tailing area. Because in deposits, through their productions in modern
Turkey, only 30–35% of the production of open and underground mines, produce the world’s
0–300 mm grain size is drawn benefit from, the cleanest and most natural raw magnesite.
remaining 65–70% of discarded material has been The caustic magnesite and sinter magnesite
transferred to the tailing area for the last 40 years, manufactory by applying the modern ore
although it contains 10–15% of magnesite. preparing methods explained here above.
Accordingly; it may be possible that approxi-
In Turkey magnesite ore being an important
mately 10–15 millions of tones of clean magnesit
industrial raw material with a good quality and
in 2–3 mm grain size to be regenerated through
big ore reserves in World and Europa markets.
flotation process.
With respect to withe colour, relative light
The regenerated fine-grain clean magnesite
density and very low magnetic susceptibility
mineral which contains 96% MgCO3 can be used
made possible to produce high quality magnesite
in the caustic or sinter magnesite production kilns.
ore and concentrate.
7. CONCLUSIONS
REFERENCES
As a result of the chromite and sepiolite resources
[1] Atak, S., Flotasyon Ilkeleri ve Uygulamaları,
in Middle Anatolia around Eskişehir known since 1990, Istanbul Teknik Universitesi Vakfı,
the 19th century. Istanbul, Turkey.
The mineralogists have come to the region [2] Gaudin, A.M., Principles of Mineral Dressing,
and have also been interested in magnesite 1939, Mc.Graw-Hill Book Company, New York,
minerals around the sepiolite reserves. USA.
Magnesite produced and caustic magnesite [3] Önal, G. and Ateşok, G., Editors, Cevher
manufactoring process was in the shaft kilns that Hazırlama El Kitabı, 1994, Yurt Madenciligini
used wood fire and that were built near the Gelistirme Vakfı, Istanbul, Turkey.
resources. [4] Petrascheck, W.E., Lagerstaettenlehre, 1961,
Springer Verlag, Wien, Austria.

MDMW Magnesite01

Uploaded by

Copyright:

Available Formats

MDMW Magnesite01

Uploaded by

Document Information

Original Description:

Original Title

Copyright

Available Formats

Share this document

Share or Embed Document

Sharing Options

Did you find this document useful?

Is this content inappropriate?

Copyright:

Available Formats

MDMW Magnesite01

Uploaded by

Copyright:

Available Formats

132 Mineral Processing Technology (MPT 2007)

Magnesite Processing in Turkey

1. INTRODUCTION The magnesite which has 50–300 mm grain sizes,

You might also like