One of the crucial points in the G U T delivery program are the chromite sand separation plants.
In comparison with silica sand chromite sand features a higher temperature resistance and a better thermal conductivity. These attributes predestinate this kind of sand especially for no-bake moulding-lines with high material accumulation and for casting materials with high casting temperatures as they are for example in steel casting. On the one hand chromite sand guarantees a high quality for several casting products, on the other hand this kind of sand amounts the cost of moulding material, if there is no internal circuit. Chromite sand is around a multiple more expensive than silica sand.
The amalgamation of chromite sand and silica sand, which arises inevitably at the shake-out station, may lead to quality problems of the casting, in case of reuse of the reclaimed sand.
With G U T plants chrome ore sand can be separated sorted from silica sand and can easily be re-used in the sand circuit for cores and moulds. The separation of single grained and dust-free sands occurs in four steps by a combined technology, two magnet-steps and “density-separation”, as well as screening technology.
In the first separation step (I) silica sand is separated by a high power magnetic drum from the magnetic particles. The silica sand can be reused directly in the sand circuit. The magnetic particles pass through the next three steps (II – IV) of the plant, where the chromite sand is refined. During this process step subversive elements like exothermic riser material are eliminated to a large extent from the sand. This procedure makes an important contribution to the amelioration of the casting’s surface.