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pearl ash [caustic koh solubles?]

updated sat 6 may 06


Jim Murphy on tue 2 may 06

I'm looking for a source of Caustic Potash [KOH].

Pearl Ash allegedly is a crude form of potassium carbonate (K2CO3) leached
from wood ashes, purified by partial crystallization and then dried by

If water is then percolated through dry Pearl Ash, will Caustic Potash (KOH)
form ?


Jim Murphy

Ivor and Olive Lewis on thu 4 may 06

Dear Jim Murphy,=20

Refined Potassium Carbonate is the product of a strong base and a weak =
acid. It hydrolyses in water to give a strongly alkaline solution. But =
its solid form can be recovered by evaporating the water, so it does not =
decompose to give Potassium Hydroxide or evolve Carbon Dioxide. =
Potassium Carbonate adsorbs Carbon dioxide from the air and being =
deliquescent, water vapour. It will readily react with strong acids.

Unlike the Alkali Earth Carbonates Potassium Carbonate does not =
decompose when heated and evolve Carbon Dioxide. It melts at 891 deg =
Celsius and is then a strong solvent for silicate minerals. This gives =
it value as a ceramic flux.

I suggest you search second hand book stalls for a copy of P.J. Durrant, =
"General and Inorganic Chemistry". Though dated, this is an excellent =
text which describes the chemistry of many common substances used by =

Best regards,

Ivor Lewis.
South Australia.

Connie Knudtson on fri 5 may 06

If you want some potassium hydroxide (KOH), call a local chemical =
company. Tell them you do not need reagent grade, which is much more =
expensive. Shipping it may involve hazardous material fees, so if you =
can get some locally, it will be less expensive.

You can also try They sell to =
soap-makers who use potassium hydroxide to make liquid soaps.

Connie Knudtson