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B Clay

Alternate Names: 3B, PR#3 B

Description: Buff firing highly vitreous, medium plasticity, stoneware clay

Oxide Analysis Formula
Na2O 0.10% 0.01
Al2O3 17.70% 1.00
MgO 0.60% 0.09
SiO2 67.80% 6.50
K2O 2.70% 0.17
CaO 0.24% 0.02
P2O5 0.02% -
TiO2 0.70% 0.05
Fe2O3 1.30% 0.05
MnO 0.01% -
LOI 6.50%n/a
SO3 0.10%n/a
Oxide Weight 525.39
Formula Weight 562.51

Notes

High temperature clean buff firing stoneware clay mined at Ravenscrag, Sask. Analysis updated July 97.

There is some argument about whether the mineralogy should be muscovite or illite. Here is the comment of one technician: "With regards to illite or muscovite, the only way to categorically differentiate between the two is to determine the layer charge (most easily by electron microscopy) which I didn't do. In this sample, the mica component has no detectable expandability which suggests a high-charge mica with very little depotassification typical of muscovites. Also, the x-ray scattering domain size is quite large with minimal disorder which you seldom find in illite but expected for muscovite. However, the kaolinite in the sample is extremely fine as one would see in fireclays. 41% quartz in the sample is accurate. You can easily verify this from your chemistry by checking the contributions of muscovite, kaolinite, smectite and K-spar to the total SiO2, and constraining potassium to
muscovite and K-spar, and Mg to smectite. From my experience, a high plasticity and the apparent illitic properties that you see in the clay is most likely due to the discrete smectite content (8%). Note that the activity of smectite is several orders of magnitude (up to 10 times) greater than the finest kaolinite or illite."

Major trace elements:
424 Ba ppm
34 Sr pmm
24 Y ppm
10 Sc ppm
249 Zr ppm
1 Be ppm
65 V ppm

Related Information

Ravenscrag Saskatchewan clays fired at cone 10R


Glazeless (top) and with glaze (bottom): A1 (bentonitic), A2 (ball clay), A3 (stoneware), 3B (porcelains), 3C (lignitic ball clay), 3D (silt). The bottom row has also shows soluble salts (SOLU test).

Mel Noble at Plainsman Clay's Ravenscrag, Saskatchewan quarry


Whitemud formation layers

Plainsman Clays extracts 6 different sedimentary clays from this quarry (Mel knows where the layers separate). The dried test bars on the right show them (top to bottom). The range of properties exhibited is astounding. The top-most layer is the most plastic and has the most iron concretion particles (used in our most speckled reduction bodies). The bottom one is the least plastic and most silty (the base for Ravenscrag Slip). The middle two are complete buff stonewares made by mother nature (e.g. M340 and H550). A2, the second one down, is a ball clay (similar to commercial products like OM#4, Bell). A2 is refractory and the base for Plainsman Fireclay. The second from the bottom fires the whitest and is the most refractory (it is the base for H441G).

Mother Nature's porcelain - From a Cretaceous dust storm!


MNP pottery mug

During a 6 week of mining in 2018 in Ravenscrag, Saskatchewan we extracted marine sediment layers of the late Cretaceous period. The center portion of the "B layer", as we call it, is so fine that it may have been wind-transported (impossibly smooth, like a body that is pure terra sigillata)! The feldspar and silica are built-in, producing the glassiest body surface I have ever seen, starting at cone 4 and lasting to cone 8. Despite this, pieces are not warping in the firings! I have not glazed the outside of this mug for demo purposes. I got away with it this time because the Ravenscrag clear glaze GR6-A is very compatible (the thermal expansion is high enough to avoid glaze compression issues and low enough not to craze). With other less compatible glazes these mugs cracked when I poured in hot coffee. To make this body I am slurrying it up as a slip and processing it to 325 mesh (using a vibrating sieve).

Links

Minerals Quartz
Quartz is the most abundant mineral on earth, it is the main crystalline mineral form of silica (SiO
Minerals Kaolinite
The most fundamental clay mineral. This mineral is found in nature in its purest form as kaolin. How
Minerals Smectite
A highly plastic clay mineral related to montmorillonite (bentonite), more correctly, the name of th
Minerals Muscovite
A form of mica often found as micro-flakes in processed raw clays. It can often be found in the mine
Minerals Illite
A clay. A sedimentary weathered alteration of muscovite mica. Some stoneware clays contain illite. I
URLs https://plainsmanclays.com/data/index.php?product=12901
B Clay Data Sheet
Materials A3 Stoneware Clay
Typecodes Clay Other
Clays that are not kaolins, ball clays or bentonites. For example, stoneware clays are mixtures of all of the above plus quartz, feldspar, mica and other minerals. There are also many clays that have high plasticity like bentonite but are much different mineralogically.
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