Andrew Reitemeyer, Facebook asked:
Waste is often burnt to produce energy. Could we use the ash from that and reclaim useful trace elements?
Yes. There are two types of ash that come from thermal treatment – one is known as incinerated bottom ash and that's the majority of it which is the clinker that drops out of the bottom of the furnace if you like. That can be safely recycled and used as good quality aggregate and that happens already. They take the metals out, any metals that are left in it, and again those various metals are recycled. The bottom ash itself is used as aggregate for road building, for block making, et cetera.
Increasingly, we’re looking to re-use that particular type of ash in the manufacture of gypsum or the replacement of gypsum for gypsum board and such like. So, science is being applied to look at new ways of recycling that because everything about both thermal treatment and energy recovery as well as the rest of the waste and recycling industry these days is all about getting the most resource efficiency that we can out of all the materials we use as a society.
As plasterboard is now banned from landfill (acidified gypsum evolves hydrogen sulphide) and the volumes of desulphogypsum from cleaning flue gasses from coal fired power stations, the volume of virgin gypsum mined in the UK has decreased drastically. (although for a long time much of the gypsum used in the UK was opencasted at Los Lesares (near Almeria) in SE Spain - europes largest gytpsum quarry)
i heard that due to prior nukebomb testings, the ash may have cesium? or whatever radioactives CZARCAR, Sat, 10th Mar 2012