Chemistry of Old Pottery

[RBlack]

Not sure if this is where to ask these questions but...What chemical changes occur when you fire clay? Is ancient pottery considered earthenware? When pottery shreds are buried in the ground do they decompose or effect the soil chemestry with ion exchange, trace elements, or any other interactions? Would pottery with glaze be any different than just fired clay?

Thanks, RB

[Tormod]

I have no clue, but maybe this may help?

Firing: What Happens to Ceramic Ware in a Firing Kiln

[Michaelangelica]

I have some info on Zeolite a clay like stuff that has properties similar to char
Email me your address and I will send them.
Hold on, I think they are advertising brochures so I may be able to post them.

[Michaelangelica]

Don'tseem to be able to post as attachments
Hope this is OK

An open mix with high air porosity and good drainage is important to
stimulate root growth and prevent many root diseases but it also leads to
rapid leaching of nutrients away from the root zones of plants.

Escott Zeolite prevents this by attracting and holding the nutrients preventing them washing through the container.

The typical approach to growing crops has been to apply high rates of fertiliser to overcome the losses due to leaching.
environmentally damaging in terms of high nutrient run off.

Escott Zeolite works as a fertiliser battery, charging when free nutrients are
available, holding them from leaching and releasing them to plant demand
as required.

Escott Zeolite is not effected by temperature and buffers the
dumping of nutrients by coated fertilisers under hot conditions holding
them for use by the plant instead of driving your dams’ E.C. through the
roof!
Use of Escott Zeolite will soak up excess ammonium and other cations in
mixes often released under hot conditions, preventing root burning.

Escott Zeolite is marginally alkaline and a source of available calcium so its use with fertilisers can help buffer pH levels thus reducing the need for lime
applications.

Zeolite carries a negative ionic charge which naturally attracts positive
charged cations like ammonium, potassium, magnesium and calcium.

The open crystalline structure of zeolite has many storage sites for these ions
which hold naturally through a loose chemical bond.

These fertiliser ions are available to plants. Zeolite has a very high cation exchange capacity and thus increases the mixes ability to hold and release nutrients. As cations are water soluble they escape from mixes by leaching.

Escott Zeolite is also an excellent capillary distributor of water due its
highly porous properties, assisting infiltration, holding water higher in the
pot and distributing water and nutrients more evenly through the mix
which is important especially under drip irrigation.

You get better value from your fertiliser dollar, improved plant growth and
reduce the nutrient load in your runoff and collected water, reducing the. . .

Sorry bit of a mess, contact these people for more info.
MA
Z e o l i t e A u s t r a l i a P t y L t d .
Escott Rd. PO Box 6 Werris Creek NSW 2341
Phone: 02 6768 7080 Fax: 02 6768 7764 Zeolite Australia - ZEL