Abstract: The invention provides a processes of producing man-made vitreous fibres having a phosphorus content of at least 0.5%, measured as weight % p2o5, comprising providing a charge of mineral material which includes briquettes, melting the charge in a furnace to provide a melt and fiberising the melt to form fibres, wherein the briquettes. comprise a non-virgin rock material comprising at least 2% phosphorus, the non-virgin rock material being selected from the group consisting of sewage sludge ash, bone meal ash, granulated sewage sludge slag and mixtures thereof.

Abstract: The invention relates to a method for preparing a mineral melt for mineral fibres production, in particular rock wool used for thermal and/or acoustical insulation or for fire protection, stock culture substrates, reinforcement, and filtering fibres. The inventive method consists in breaking and compacting at least industrial residual materials and correction materials which are used for regulating the required composition and viscosity of the mineral melt with a bonding agent in such a way that moulded pieces can be formed and, afterwards transferred to a melting unit. The aim of said invention is to improve a method for the preparation of a mineral melt for producing rock wool in a low-cost manner optimizing properties of produced mineral fibre articles.