The present invention relates to inorganic fibres having a composition comprising: 65.7 to 70.8 wt % SiO.sub.2; 27.0 to 34.2 wt % CaO; 0.10 to 2.0 wt % MgO; and optional other components providing the balance up to 100 wt %,
wherein the sum of SiO.sub.2 and CaO is greater than or equal to 97.8 wt %; and the other components, when present, comprise no more than 0.80 wt % Al.sub.2O.sub.3; and wherein the amount of MgO and other components are configured to inhibit the formation of surface crystallite grains upon heat treatment at 1100° C. for 24 hours, wherein said surface crystallite grains comprise an average crystallite size in a range of from 0.0 to 0.90 μm.

A process for the manufacture of inorganic fibres comprises: (a) selecting a composition and proportion of: (i) silica sand; (ii) lime comprising at least 0.10 wt % magnesia; and (iii) optional additives comprising a source of oxides or non-oxides of one or more of the lanthanides series of elements, or combinations thereof; (b) mixing the silica sand; lime; and optional additives to form a mixture; (c) melting the mixture in a furnace; and (d) shaping the molten mixture into inorganic fibres. The raw materials selection comprises composition selection and proportion selection of the raw materials to obtain an inorganic fibre composition comprising a range of from 61.0 wt % and 70.8 wt % silica; less than 2.0 wt % magnesia; less than 2.0% incidental impurities; and no more than 2.0 wt % of metal oxides and/or metal non-oxides derived from said optional additives; with calcia providing the balance up to 100 wt %; and wherein the inorganic fibre composition comprises no more than 0.80 wt % Al.sub.20.sub.3 derived from the incidental impurities and/or the optional additives.

A blast furnace for ironmaking production wherein iron ore is at least partly reduced by a reducing gas which is injected in the stack of the blast furnace. The blast furnace includes an external and an internal wall, having a thickness T.sub.int, in contact with matters charged into the blast furnace. The thickness T.sub.int of the internal wall is substantially constant above and below the injection area of a reducing gas.

This invention refers to a technically and economically viable process for recovery of relevant metallic and non-metallic contents from mining residues, particularly the bauxite residue, using it in its integral form. Such a process route uses energy from microwaves, assisted leaching and logic sequencing of steps that allow a technically and economically viable removal of components from the bauxite residue, particularly the residue from the Bayer process. The invention also refers to a microwave reactor that is appropriate for performing the above-mentioned process, as well as to a method for heating a mining product.

The present invention relates to inorganic fibres having a composition comprising: 61.0 to 70.8 wt % SiO.sub.2; 28.0 to 39.0 wt % CaO; 0.10 to 0.85 wt % MgO other components, if any, providing the balance up to 100 wt %, The sum of SiO.sub.2 and CaO is greater than or equal to 98.8 wt % and the other components comprise less than 0.70 wt % Al.sub.2O.sub.3, if any.

The present invention relates to inorganic fibres having a composition comprising: 61.0 to 70.8 wt% SiO.sub.2; 28.0 to 39.0 wt% CaO; 0.10 to 0.85 wt% MgO other components, if any, providing the balance up to 100 wt %,

The sum of SiO.sub.2 and CaO is greater than or equal to 98.8 wt % and the other components comprise less than 0.70 wt % Al.sub.2O.sub.3, if any.

A system for conditioning stucco particulate material includes a vessel having separation chamber in communication with a holding chamber having a holding volume therein. The conditioning system includes the holding volume sufficient to condition the stucco particulate material therein and/or a control system configured to delay discharge of the stucco particulate material from the holding chamber. The system for conditioning stucco particulate material is configured to increase residence time of the stucco particulate material in the holding chamber to promote calcining conditioning therein.

A method for protecting an inner wall (12) of a shaft furnace, the method comprising the steps of: providing at least one injection device (28) through the inner wall (12) of the shaft furnace, the injection device (28) being configured to inject protective material into the shaft furnace; and injecting on demand the protective material into the shaft furnace through the injection device (28), in such a manner that the protective material builds up to form a protection wall between the interior of the shaft furnace and the furnace wall (12).

Taper plate assemblies are disclosed that may be installed on the top of steel casting ladles to restrain and maintain refractory lining materials in compression during casting operations. The taper plate assemblies include a generally conical taper plate supported by a ring-shaped support flange and a support collar. The taper plate is located at least partially above a refractory top ring that may comprise a castable refractory material, and is designed to maintain the refractory top ring in compression during multiple casting operations.

A lining structure for a refractory vessel contains a first layer containing refractory material; a second layer, in communication with and parallel to the first layer, containing a metal layer or component; and a third layer, in communication with and parallel to the second layer, containing refractory material. The metal component in the second layer contains filled transverse passages, between the surface of the second layer in contact with the first layer and the surface of the second layer in contact with the third layer, producing support structures to maintain the structural integrity of the refractory vessel in use.