The effect of dispersants on the properties of low-cement concrete for the furnace of smelting of jewelry waste

Melting in ceramic crucible is one of the stages of recycling jewelry production. Conceptivity of concrete mass plays an important role in molding a large-scale refractory crucible to vibration. The impact of a number of commercially available dispersants (CASTAment FS 10, MELFLUX 1641 F, peramin al 200, FF7 SPEZIAL and PC-1701) on the rheology of the low-cement concrete mass of corundo-mullite-zirconium composition and the physico-mechanical properties of the material are considered. The best results were obtained using the PC-1701 dispersant.

The optical determination of high metallurgical temperatures - The melting point of iron

The present investigation has been carried out in the Metallurgical Department of the National Physical Laboratory in order to adapt the optical pyrometer to the estimation of the fusion temperatures of materials of high purity and high melting point and of substances of corrosive or volatile nature. Melting points and thermal changes in the solid state at high temperatures are generally determined by means of platinum thermocouples which are protected from the molten metal or its vapour by insertion in a refractory sheath. Contamination of the molten metal is frequently occasioned by chemical attack which takes place between the metal and the refractory crucible or couple sheath. This is particularly marked when the refractories contain siliceous material.