Questions about coir and slag

Pat Colville
Tue, 15 Jul 2003 15:26:16 PDT
Arnold-  Slag is not pure iron, it is the light molten fraction that floats
above the dense pure iron in the blast furnace refining process.  It is high
in calcium, silica, with magnesium, alkalis, iron and many other trace
elements that are present in iron ore or added to make specialty steels.
Elements like manganese, cobalt, chromium and maybe sulfur.
Most slags that I have used in industrial applications are rather alkaline
and I would expect the leachate to be alkaline.  I can't imagine using it on
or around growing plants unless they are alkali loving types. At a steel
mill near here there were large slag heaps over twenty years old with still
nothing but a few grasses growing on them. This makes me think slag could be
used along gravelly garden paths to keep grass and weeds out. Could that be
what this "Black Beauty" stuff is meant for?

However, fast quenched slag can be frothy like lightweight aggregate or
similar to pumice.  In that case, I would recommend using it in Hypertufa
trough construction but not as a soil component.

Pat Colville

2. I picked up some slag ( Black Beauty)  and would like to use it to 
dress some potted tender bulbs that I place outdoors for the summer.  I 
know it is basically pure iron, any down sides to using it like leaching 
poisons in to the soil..


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