Dr. Beyhan Ozdemir, KUMAS Kutahya Manyezit Isletmeleri A.S.

Cryptocrystalline and macrocrystalline magnesite ores

1

CONTENTS

1. Objective

2. Types of natural magnesite deposits

3. Examination and evaluation of magnesite ore

4. Microstructures SEM, XRD and TG-DTA analysis results

5. Firing of samples and results

- Single firing results

- Double firing results

6. Conclusion

2

OBJECTIVE

In this study, brickmaking grades of high quality magnesite resources were compared.

two cryptocrystalline magnesite samples

FROM TURKEYKUMAS MINE

FROM AUSTRALIA

one macrocrystalline magnesite sample

FROM CHINA

COMPARISION OF MAGNESITE TYPE

&

3

TYPES OF NATURAL MAGNESITE DEPOSITS

4

1- Serpentine Alteration by Hydrothermal Process – CO2 rich waters alter magnesium-rich serpentinite

3- Sedimentary Type- Ultrabasic rock may be weathered, eroded and transported to lake to

precipitate magnesite

4- Replacement of Limestone and Dolomite - Magnesia rich fluids attack dolomite or limestone.

CRYPTOCRYSTALLINE / AMORPHOUS MAGNESITE Turkey, Greece, Australia, Albania, Egypt, Iran, Nepal

MACROCRYSTALLINE /SPARRY /BONE MAGNESITE Austria, Slovakia, Spain, Canada, Brazil, Southern India (Uttar Pradesh),

China, North Korea, Russia

2- Magnesite Formation by Infiltration- the weathering of serpentine by CO2-laden waters

5

Source: 1- “World Resources of Magnesite and Market Utilisation”, Ian Wilson, IM MagMin, Amsterdam, May 20092- “The Industrial Minerals Handy Book”, a guide to markets, Peter W. Harben3- “The Chemistry and Technology of Magnesia”, Mark A. Shand

CRYPTOCRYSTALLINE / AMORPHOUS

MAGNESITE

MACROCRYSTALLINE /SPARRY /BONE

MAGNESITE

Marble like crystallinity

Often of high quality with low CaO, Fe2O3 Higher Fe2O3 and impurities

Generally white color Various colors, but color doesn’t reflect grade.

Present in huge depositsTends to occur in smaller and shallow deposits

Present in veins and stockworks.

Fine crystal size 1-10 micron Large crystal size in cms.

Massive with a characteristic conchoidal fracture

6

Source: 1- “World Resources of Magnesite and Market Utilisation”, Ian Wilson, IM MagMin, Amsterdam, May 20092- “The Industrial Minerals Handy Book”, a guide to markets, Peter W. Harben3- “The Chemistry and Technology of Magnesia”, Mark A. Shand

TYPES OF NATURAL MAGNESITE DEPOSITS

Source: Ian Wilson, November 2-4th 2011 Hangzhou, China

7

Examination and evaluation of magnesite ore

8

Experimental procedure

Analysis on magnesite

ore samplesChemical analysis

XRF

Microstructures analysis

SEM

Porosity Bulk densityASTM C 830

Thermal decomposition

TG-DTA

Mineralogical analysis

XRD

Visiualappearance

9**All this studies was done at laboratory scale.

APPEARANCE TO THE NAKED EYE

Cryptocrystalline1

Macrocrystalline From China

Cryptocrystalline2

10

Cryptocrystalline 1

11

Cryptocrystalline 2

12

Macrocrystalline From China

13

Results on Chemical Composition

Cryptocrystalline 1

Cryptocrystalline 2

Macrocrystalline From China

SiO2 0.22 0.14 0.41

CaO 0.73 0.62 0.65

Fe2O3 0.27 0.08 0.51

Al2O3 0.04 0.02 0.02

MgO 47.51 47.62 47.13

Na2O 0.125 0.098 0.154

MnO 0.002 0.047 0.013

LOI 51.11 51.38 51.13

14

Physical Properties

Cryptocrystalline 1

Cryptocrystalline 2

Macrocrystalline From China

Porosity (%) 10.62 10.31 0.73

Bulk Density (gr/cm3) 2.62 2.62 2.98

Water Absorption (%) 4.06 3.96 0.34

15

MICROSTRUCTURES

BY SEM EXAMINATION

16

Cryptocrystalline 2

Cryptocrystalline 1

Macrocrystalline From China

100 X

17

4400 micron

1000 X

Cryptocrystalline 2

Cryptocrystalline 1

Macrocrystalline From China 18

380 micron

5 000 X

Cryptocrystalline 2

Cryptocrystalline 1

Macrocrystalline From China 19

80 micron

10 000 X

Cryptocrystalline 2

Cryptocrystalline 1

Macrocrystalline From China 20

35 micron

20 000 X

Cryptocrystalline 2

Cryptocrystalline 1

Macrocrystalline From China 21

18 micron

30 000 X

Cryptocrystalline 2

Cryptocrystalline 1

Macrocrystalline From China 22

10 micron

Mineralogical Structures by XRD

Macrocrystalline From China

Cryptocrystalline 1

Cryptocrystalline 2

23

Thermal Analysis Results TG-DTA

Macrocrystalline – 6780C

Cryptocrystalline 1- 6400C

Cryptocrystalline 2 – 6520C

24

FIRING OF SAMPLES AND

RESULTS

25

Experimental procedure

A- SINGLE FIRING

Calcinationat 7000C

Calcinationat 10000C

Firing at 17000C

26

Calcination at 7000C

Cryptocrystalline2

Macrocrystalline From China

Cryptocrystalline1

27

Calcination at 10000C

Cryptocrystalline2

Macrocrystalline From China

Cryptocrystalline1

28

20 000 X

Cryptocrystalline 2

Cryptocrystalline 1

Macrocrystalline From China 29

18 micron

Firing at 17000C

Cryptocrystalline2

Macrocrystalline From China

Cryptocrystalline1

30

BULK DENSITY VALUES after calcination (gr/cm3)

31

POROSITY VALUES after calcination(%)

32

BULK DENSITY VALUES after single firing (gr/cm3)

33

Experimental procedure

A- DOUBLE FIRING

Calcinationat 10000C

Grinding

Briqueting Firing at 17000C

34

FIRING TESTS RESULTS after double firing

Cryptocrystalline1

35

2000 X

FIRING TESTS RESULTS after double firing

Cryptocrystalline2

36

2000 X

FIRING TESTS RESULTS after double firing

Macrocrystalline From China

37

2000 X

MgO 29.13

SiO2 40.03

CaO 30.85

Grain Boundry Phase

FIRING TESTS RESULTS after double firing

38

CONCLUSION

1. Macrocrystalline magnesite ore structure has very low porosity amounting to 0,7% whereas cryptocrystalline has 10,3% and 10,6%. Accordingly, same tendency was observed in the bulk density results . Macrocrystalline magnesite structure has 2.98 gr/cm3 bulk density, but cryptocrystalline is lighter with a density of 2.62 gr/cm3.

2. According to TG-DTA analysis cryptocrystalline magnesite has lower decomposition temperature than macrocrystalline magnesite

3. The super fine crystal structure of the cryptocrystalline magnesite results in the formation of high levels of porosity during the calcination process. Most probably it will have higher SSA.

4. High bulk density values were determined after single firing of cryptocrystalline magnesite samples. In contrast,disintegration took place after single firing of macrocrystalline magnesite . Therefore, macrocrystalline magnesite is not suitable for use in the single firing DBM production process because of its very high crystal size. Higher DBM densities can be reached by using double firing production process for macrocrystalline magnesite .

5. Double firing test results showed that cryptocrystalline magnesite ore samples had higher bulk density values than macrocrystalline magnesite ores under similar firing conditions.

39

Thanks for your kind attention

40