From LouisKatz

Soluble: AluminumSalts

Soluble Aluminum Salts

Aluminum Sulphate, Alum is used as a coagulant in water treatment. It brings together large flocs which then drop out of solution and/or are filtered out. This is not intuitive to clayers. We add flocculants to thicker suspensions to keep them from settling out. In thicker suspensions with clay colloids this creates light flocs full of water. While the don't always completely stay in suspension, if there is enough clay then a large house of cards structure is formed from the clay that seems to physically prevent materials from settling to the bottom as a hard pan. It would be a disaster in a glaze bucket if you don't need it so make sure it is only used after a glaze. It produces a dull white scum that looks like scumming on bisque but holds up to cone ten. I like it, but its use is limited. I do not know how thick it can be used.

I wonder if it would be helpful on top of flashing slips but have seen no highly promising results. I have not done careful testing with it. This chemical is available in garden nurseries. I wonder about its use with Iron Sulphate to form orange surfaces. It likely reacts with other soluble materials. I do not know which ones.

It is available in some Asian Grocery stores in small quantities. It maintains color and crispness in canned and maybe cooked vegetables. It is used in very small quantities. I have not used it in food or clay. Like alumina sulfate above I wonder if its use with Copperas (iron sulfate) would result in orange iron aluminates on the surface.

Aluminium hydroxide is mostly insoluble in water but is soluble in acids such as the one formed when aluminum chloride is mixed with water.

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Page last modified on May 10, 2018, at 01:27 PM