Michael Banks on tue 12 jan 99
You are probably wise to be wary of ground ilmenite that is too pale in
colour Peter.
Unlike rutile, ilmenite in nature does not vary enormously in chemical
composition, the Ti and Fe content only varying a few percent (less than
ten) between different sources. In rutile the same two elements vary by up
to 2 and 20 times respectively.
So different rutile batches can look quite different in colour, but ilmenite
should always look black. Unless it is contaminated with significant
dilutants such as light coloured silicates, or maybe it is not ilmenite at
all.
A useful test to differentiate between ilmenite and rutile is to do a streak
test. Smear out some grains on the surface of a piece of porcelain or
vitreous china tile. Ilmenite has a black streak, sometimes with a hint of
dark brown. Rutile has a pale brown to tan streak.
Another test is to use a strong hand lens or other magnifying device, such
as a microscope to have a look at the sample. Wetting the sample will help.
Ilmenite is always opaque black. There is not the slightest transparency.
Rutile is usually a translucent or transparent reddish to brownish colour.
Silicate contaminants are generally very light in colour when fine grained.
Something I would recommend to potters who are dependant on industrial
mineral colourants such as ilmenite being reliable, is to do fusion button
tests. These can be a standard mixture of the colourant and soda ash or
borax which can be fired in a depression in a small test tile. In many
cases these can be put in a bisc firing and kept as a file reference to
moniter variations in raw materials.
Michael Banks
Nelson,
New Zealand
mjbanks@clear.net.nz
-----Original Message-----
Abridged
...........there is a major difference in appearance
compared to the old stuff. The new is definitely a fine
dark gray powder and looks a lot like a very dark rutile.....
Michael Banks on wed 27 jan 99
Hello Cheryl,
You will need to find out if your local beach has any significant rutile
content, so I suggest you obtain a prospecters panning dish (the black
plastic ones are OK) and a shovel, go down the beach and pan youself a heavy
mineral sample. Your beach does not need to have a commercially economic
rutile deposit on it to be a useful source for you own consumption.
The best place to get this is to study the beach and observe where heavy
mineral strand lines have formed. These are visible as dark grey or black
bands parallel to the surf and the richest accumulation is usually at the
head of the beach at the point where storm waves stop at high tide. If sand
dunes are present, the richest strand line is just down slope of the base of
the dunes.
If the beach has a headland at one end (or other natural or man-made
obstacle), the richest heavy mineral strand deposit will be also in the
immediate lee of the headland. You will need to work out which way the sea
runs to identify the lee side. You may find that thick concentrated heavy
mineral deposits (minerals of density 4 or more) lie under a layer of
pale-coloured light mineral sand (density of 2.5). The best time to collect
heavy mineral concentrates is usually after storms which "cut" the beach.
The higher energy than normal waves deposit more heavy sands (zircon,
ilmenite, rutile etc) and wash away a lot of light minerals such as quartz
and feldspar.
When you have a bucket of heavy mineral sand from panning at the beach (you
will need to teach yourself or get help), take it home and pan it again,
this time carefully into fractions. With practice using a smaller panning
dish, you will be able to separate several different coloured sand
fractions. In New Zealand these normally consist of:
1. Light Heavies (dark green to red): consisting of epidote, hornblende,
garnet (fairly useless in ceramics but may be worth experimenting with).
2. Ironsand (black): consisting of ilmenite and magnetite plus or minus
rutile.
3. Zircon-monazite (silvery white to yellow): consisting of variable ratios
of amounts of zircon, monazite and rutile (and sometimes gold and
latinum - depending on where you are).
In Florida I have no knowledge of the heavy mineral suite, but since rutile
is mined there, fraction 3 should have a lot of rutile in it and possibly
fraction 2 also. Rutile sand is usually brownish in colour and with careful
and diligent panning and repanning of fraction 3 or 2, you should be able
separate a rutile concentrate by colour.
Fire small samples of all your mineral fractions along with a flux (such as
soda ash or feldspar) as experiments. Compare with your commercial rutile
etc. You may have to grind up your rutile con if you're used to fine mesh
material.
If you wish to separate ilmenite from the ironsand fraction, remove the
magnetite (black iron spangles) from the con with a magnet. Discard the
Light Heavy fraction and the zircon-monazite fraction after you've got the
rutile out. The monazite is radioactive and so is the zircon to a lesser
extent. Return it to the beach to help tan the tourists!
Let me know how you get on,
Michael Banks
Nelson,
New Zealand
mjbanks@clear.net.nz
>>----------------------------Original message----------------------------
>>Dear Edouard:
>>
>>I live in Florida close to the beach, and I also use rutile in my glazes
>and slips. How does one extract the rutile from the beach sand? I would
like
>to incorporate this natural material into my glazes.
Edouard Bastarache on mon 26 mar 01
Hello all,
I just had this morning a talk with an engineer working for QIT-Fer & =
Titane (QIT stands for Quebec Iron & Titanium), we have been friends =
since elementary school.
QIT owns an ilmenite mine in northeastern Quebec.The deposit is large =
enough to produce for the next 40 years; they extract 3,000,000 tons a =
year. 10% is shipped directly from the mine to the steel industry. Most =
of the ore is shipped to Sorel-Tracy where it is processed into titanium =
dioxide slags, iron pigs, iron and steel powders (their iron powder is =
added to cereals), steel billets and steel autoparts. One of their slags =
(UGS) is a synthetic rutile I use in my own glazes.
There are other deposits in other countries where ilmenite is gathered =
from beach sands as in South Africa and Madagascar (these stuffs have a =
finer particle size distribution compared to the ore mined by QIT).
We feel there is no ilmenite shortage. But since we use less than 1% of =
the raw materials prepared for the ceramics industry, the availability =
of it from raw materials distributors for potters may be determined by =
the needs of the industry. But the supply of unprocessed ilmenite ore is =
sufficient.
Later,
Edouard Bastarache
Irr=E9ductible Qu=E9becois
Sorel-Tracy
Dans / In "La Belle Province"
edouardb@sorel-tracy.qc.ca
http://www.sorel-tracy.qc.ca/~edouardb/
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