Crude and Expanded Vermiculite
Crude and Expanded Vermiculite

VERMICULITE

Naturally Occuring, Safe, and Plentiful


Welcome to the Website About Vermiculite




This site was designed as a basic introductory page on some of the technical characteristics of vermiculite. We also have include a listing of many helpful web sites, and hope you will launch from here to find out how vermiculite is used, how it is mined and processed, and how it is incorporated into many products.

Essentially vermiculite is a member of the phyllosilicate group of minerals, resembling mica in appearance. It is found in various parts of the world, but currently the major mines are located in South Africa, China, Brazil, Zimbabwe, and the United States. The largest operating mines today are located in the Palabora region of North-Eastern Transvaal in South Africa, in the northwestern corners of China, and along the eastern Appalachian range in the United States (Virginia and South Carolina). The vermiculite ores from these mines are different forms of hydrated phlogopite or biotite mica which has the remarkable ability of being able to expand to many times its original volume when heated---a property known as exfoliation.

From a geological perspective, almost all of the commercial vermiculite mines operating today work in deposits which were formed in pre-Cambrian and Archean deposits (1.5-3.0 billion years old). These are quite different from the former Libby, Montana deposit which was Triassic in age (225 million years old).

The Palabora Vermiculite Mine

The Palabora Vermiculite Mine

Recently there has been a lot of confusion about vermiculite and asbestos. Recent newspaper articles, a 20/20 show, National Public Radio, McCall's magazine, and Newsweek, for instance, have addressed problems at the former Libby, Montana mine which has been closed since 1990. These problems were very real, and continue to be a great concern to everyone affected---especially to the many miners and their families who worked in Libby.

Current manufacturers of vermiculite have known about this problem for years, and have had their material checked for possible asbestos contamination.

At The Schundler Company in New Jersey, for instance, during an inspection in early 2000, the federal Environmental Protection Agency tested vermiculite samples from 12 random piles of South African vermiculite, and could not find any asbestos in any of the samples. Also during 2000, testing at the Dillon, Montana mine by MSHA found no asbestos fibers. The results of other testing will be posted as soon as the final reports are completed, but so far initial reports from the other operating mines in North America are looking very, very good!

For more information, look at some of these pages:


For information about the many uses of vermiculite in horticulture, construction, and industrial applications, there are a number of helpful and useful web sites which you might want to peruse.

Having been in the vermiculite business for three generations, we believe the most complete site about the many uses of vermiculite is our own 165 page web site at:

Good luck, and thank you for your interest in vermiculite!!


Pictures of Unexpanded and Expanded Vermiculite

Vermiculite: Unexpanded, Expanded and a Single Particle

TYPICAL CHEMICAL ANALYSIS
Element
Percent by Weight
SiO2
38-46
AL2O3
10-16
MgO
16-35
CaO
1-5
K2O
1-6
Fe2O3
6-13
TiO2
1-3
H2
8-16
Other
0.2-1.2


Typical Chemical Formula: (Mg,Ca,K,Fe11)3(Si,AL,Fe111)4O10(OH)2O4H2O




TYPICAL PHYSICAL PROPERTIES
Color
Free Moisture, Maximum
pH (of water slurry)
Specific Gravity
Expanded Bulk Density (normal)
Mesh Sizes (normal)
Fusion Point
Specific Heat
Thermal Conductivity

Gold-Brown
0.5%
7.0-9.5
2.5
4-10 lb/ft3
2-40 mesh and finer
2200-2400F
1.08 kJ/kg.K
.27-.41 BTU.in/h.ft2.F


TYPICAL SIZES, DENSITIES, AND NAMES
OF EXPANDED VERMICULITE
1

SIZESDENSITIESGRADES OR SIZES
MMINN/AKG/CU MLB/CU FTU.S. SYSTEMINTERNATIONAL
165/8DOWN56-723.5-4.5N/APremium (6)
85/16DOWN64-854.0-5.01Large (4)
45/32DOWN72-904.5-5.52Medium (3)
20.08DOWN75-1124.7-7.03Fine (2)
10.04DOWN80-1445.0-9.04Super Fine (1)
0.50.02DOWN90-1605.6-10.05Micron (0)
NOTES:

  1. These sizes and values are given for general information purposes only. All manufacturers do not necessarily produce all these grades, and many use grades which may not conform to these specifications at all times.




The Vermiculite Institute
c/o The Schundler Company
150 Whitman Avenue,
Edison, New Jersey 08817
(ph)732-287-2244 (fax) 732-287-4185
email: info@schundler.com