Safety Data sheet

Vermiculite - material safety

Technical Specification: Crude & Exfoliated Vermiculite

Crude vermiculite from the Palabora mine consists of golden/brown flakes which are carefully classified into different grades each with a specified range of particle sizes, as detailed in the table below. Vermiculite is most widely used in its exfoliated form. The concertina-shaped granules of exfoliated vermiculite are non-combustible as well as being insoluble in water and all organic solvents. Completely safe and easy to handle, exfoliated vermiculite is available in different grades.

Palabora Vermiculite: Typical Specification
Vermiculite Crude Vermiculite Exfoliated Vermiculite
No Grade (1) Size (mm) (2) Density (kg/m3) (3) Yield (m3) (4) Density (kg/m3)
4 Large - 8.0 + 2.8 700 - 850 12.0 - 14.5 60 - 75
3 Medium - 4.0 + 1.4 800 - 950 10.0 - 13.0 70 - 85
2 Fine - 2.0 + 0.71 850 - 1050 8.0 - 11.5 75 - 85
1 Superfine - 1.0 + 0.355 850 - 1050 7.0 - 10.0 85 - 100
0 Micron - 0.71 + 0.25 850 - 1050 6.0 - 9.0 105 - 135
Supermicro 1.0 + 0.25 850 - 1050 6.2 - 9.0 90 - 135
RSU - 0.5 + 0.18 850 - 1050 3.0 - 5.0 115 - 150
DDM - 0.1 + 0.0 1250 - 1550 2.0 - 2.5 350 - 400
Notes:
(1) Particle size distribution minimum 80% retained (mm).
(2) Loose bulk density of product (kg/m3).
(3) Typical volume yields (cubic metres of exfoliated vermiculite) per tonne of crude vermiculite processed (m3).
(4) Typical loose bulk density of product (kg/m3).


The typical loose bulk densities and volume yields for exfoliated vermiculite produced in the table above are values obtained by commercial operation of an S.S.T. Rotary Exfoliator. These values may vary slightly depending on the type of furnace used, the efficiency of the production system and on the feed rate of the crude vermiculite into the furnace.

Chemical Analysis: Crude & Exfoliated Vermiculite

When analysed chemically, crude and exfoliated vermiculite give the same values. Because vermiculite is a naturally occurring substance its exact composition may vary from sample to sample.

Typical Ranges for Major Components
SiO2 Silicon Dioxide 35 - 41%
Al2O3 Aluminium Oxide 6.0 - 9.5%
Fe2O3 Iron Oxide 6.0 - 9.5%
MgO Magnesium Oxide 21.5 - 25.5%
K2O Potassium Oxide 3 - 6%


Typical Ranges for Minor Components
CaO Calcium Oxide 2.0 - 6.0%
CO2 Carbon Dioxide 0.6 - 2.5%
TiO2 Titanium Dioxide 0.6 - 1.4%
F Fluorine 0.2 - 0.8%
Cr2O3 Chrome Oxide 0.01 - 0.15%
P2O5 Phosphorus Pentoxide 0.2 - 2.0%
Cl Chlorine 0 - 0.5%

Specific Surface Area: Exfoliated Vermiculite

The specific surface area for exfoliated vermiculite, as measured by the nitrogen absorption technique, is typically:

Exfoliated vermiculite
No Grade M2/g No Name M2/g>
4 Large 3.4 Supermicro 6.0 *
3 Medium 4.0 RSU 7.2
2 Fine 4.4 DDM 7.5
1 Superfine 5.4
0 Micron 6.4

* Not determined by nitrogen absorption but calculated from Superfine and Micron values.

Absorption Capacity: Exfoliated Vermiculite

All grades of exfoliated vermiculite will retain liquids within the inter-laminar voids of the individual particles as well as between the particles themselves.

This table gives an indication of the quantity of liquid which can be retained using Superfine grade vermiculite before drainage of the liquid occurs.

Liquid Volume of Liquid Absorbed in 1 Litre of Vermiculite (ml)
DDM RSU Micron Superfine Fine Medium Large
Water 517 457 406 310 280
Diesel Oil 454 335 273 213 183
Heavy Gear Oil 488 411 353 268 174
15/40 Multigrade Oil 543 356 350 262 193
Note:
(a) Diesel oil used in the test is 35 second gas oil, which is very similar to paraffin.
(b) 15/40 Multigrade oil is oil that meets certain low-temperature and high-temperature requirements simultaneously and is commonly used as engine oil.
(c) Absorption is related to surface area of the particle and the finer grades have, on a volume basis, more surface area than the coarser grades (i.e. Large Grade).

Other supporting technical data: Crude Vermiculite



Angle of Repose This varies from 38 to 26 according to grade
Melting Point Collapse and coalescence of the individual flakes begins at 1330C
Specific Heat 1.03 kJ/kg.K. at 20C
1.05 kJ/kg.K. at 30C
Specific Gravity 2.5 to 2.6 depending on grade
Mohs Hardness Between 1 & 2
pH Value Crude Vermiculite: 8.5 to 10
Weight Loss At 105C - 4.5 to 6.5%
At 950C - 8.0 to 10.0%

Note: (a) At the lower temperature all the weight loss will be water. (b) At the higher temperature most of the weight loss will be water but some will be volatile components such as carbon dioxide.
Aspect Ratio: Ratio of flake diameter to flake thickness As received, this varies from 7:1 to 30:1 depending on grade.
Mechanical processing can produce aspect ratios of 50:1.
Chemical and mechanical processing can produce ratios of 200:1.

Note: The higher the aspect ratio the thinner the vermiculite flake.
Cation Exchange The exchangeable cation normally present in vermiculite is Magnesium. The cation exchange capacity of Palabora Vermiculite is up to 600 milliequivalents per kg. The rate of cation exchange will depend on exposed surface area; therefore, the best results are obtained using exfoliated vermiculite.


Disclaimer: The details contained in this document are provided as a source of information and for guidance only. Whilst every effort is made to ensure the content is accurate and up to date, use of the information contained in this document is solely at the discretion, risk and liability of the recipients.

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PALABORA COPPER (PTY) LIMITED
Phalaborwa, Limpopo , South Africa
T: +27 (0)15 780 2911
PO Box 65, 1 Copper Road, 1389
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