Abstract: Feeders for use in the foundry industry comprising (a) rice husk ash containing, based on the total amount of the constituents detectable in the rice husk ash by quantitative phase analysis by means of x-ray diffractometry (i) crystalline modifications of silicon dioxide, (ii) monoclinic feldspar and (iii) amorphous silicon dioxide, a total content of at least 70 wt. %, preferably more than 75 wt. % of (i) crystalline modifications of silicon dioxide and (ii) monoclinic feldspar, wherein, based on the total weight of the shapeable composition of the feeder, the amount of this rice husk ash is in the range of from 5 to 50 wt. %, preferably 5 to 25 wt. %, (b) cured binder, (c) optionally fiber material, (d) optionally one or more further fillers, and (e) optionally an oxidizable metal and an oxidizing agent for the oxidizable metal are described.

Abstract: The present invention relates to a core-sheath particle for use as filler for feeder compositions for the production of feeders, comprising (a) a carrier core which has a size within a range of from 30 ?m to 500 ?m and consists of a material which is maximally resistant up to a temperature of 1400° C. and does not contain any polystyrene, (b) a sheath which encloses the core and consists of or comprises (b1) particles having a D 50 value for the particle size of at most 15 ?m, which are resistant up to a temperature of at least 1500° C., and (b2) a binder which binds the particles to one another and to the carrier core, the core-sheath particle being resistant up to a temperature of at least 1450° C.

Abstract: Feeders for use in the foundry industry comprising (a) rice husk ash containing, based on the total amount of the constituents detectable in the rice husk ash by quantitative phase analysis by means of x-ray diffractometry (i) crystalline modifications of silicon dioxide, (ii) monoclinic feldspar and (iii) amorphous silicon dioxide, a total content of at least 70 wt. %, preferably more than 75 wt. % of (i) crystalline modifications of silicon dioxide and (ii) monoclinic feldspar, wherein, based on the total weight of the shapeable composition of the feeder, the amount of this rice husk ash is in the range of from 5 to 50 wt. %, preferably 5 to 25 wt. %, (b) cured binder, (c) optionally fibre material, (d) optionally one or more further fillers, and (e) optionally an oxidizable metal and an oxidizing agent for the oxidizable metal are described.

Abstract: The present invention relates to a core-sheath particle for use as a filler for feeder masses for the production of feeders, comprising (a) a carrier core having a size of 30 ?m to 500 ?m and composed of a material, which is resistant up to a maximum temperature of 1400° C. and contains no polystyrene, (b) a sheath surrounding the core composed of or comprising (b1) particles having a maximum D 50 value for grain size of 15 ?m and resistant up to a temperature of at least 1500° C., and (b2) a binding agent binding the particles to one another and to the carrier core, wherein the core-sheath particle is resistant to temperatures up to 1450° C.