Disclosed herein is a mud material comprising a refractory raw material, an organic binder, and a curing agent, wherein part or all of the organic binder is a novolac-type phenol resin, part or all of the curing agent is a methylene donor, and wherein the methylene donor is at least one selected from the group consisting of hexa(methoxymethyl)melamine and hexamethoxymethylolmelamine.

A method of sealing a slag drain in a direct smelting vessel is disclosed. Also disclosed are a method of maintaining a slag drain channel and a direct smelting vessel with a slag drain channel that extends through a sleeve of refractory material installed in the direct smelting vessel. The method for sealing the slag drain includes locating a pre-formed refractory material at an inlet end of the slag drain channel so that it is exposed to a molten bath contained within the direct smelting vessel and sealing the slag drain channel with sealing material downstream of the pre-formed refractory material.

Exemplary embodiments of mud gun caps are disclosed herein. An exemplary mud gun cap includes a flame-resistant body that has a tap hole contacting surface. The flame-resistant body has side wall; a first bore and a second bore located within the flame-resistant body. The first bore has a first diameter and second bore has a second diameter. The first diameter is smaller than the second diameter and the second bore is located farther away from the tap hole contacting surface than the first bore.

A method of sealing a slag drain in a direct smelting vessel is disclosed. Also disclosed are a method of maintaining a slag drain channel and a direct smelting vessel with a slag drain channel that extends through a sleeve of refractory material installed in the direct smelting vessel. The method for sealing the slag drain includes locating a pre-formed refractory material at an inlet end of the slag drain channel so that it is exposed to a molten bath contained within the direct smelting vessel and sealing the slag drain channel with sealing material downstream of the pre-formed refractory material.

Exemplary embodiments of mud gun caps are disclosed herein. An exemplary mud gun cap includes a flame-resistant body that has a tap hole contacting surface. The flame-resistant body has side wall; a first bore and a second bore located within the flame-resistant body. The first bore has a first diameter and second bore has a second diameter. The first diameter is smaller than the second diameter and the second bore is located farther away from the tap hole contacting surface than the first bore.

A drill bit for improving performance of a drilling machine is provided. The drill bit includes a drill bit body with a rear end adapted to be connected to a drilling machine, and a leading end with a flat face perpendicular to a longitudinal axis (X-X) of the drill bit body. The drill bit body includes a first tapered portion with diameters increasing from the flat face of the leading end to a maximum diameter (Dmax), a second tapered portion with diameters decreasing from the maximum diameter (Dmax) to the rear end of the drill body, at least three partly-circular recesses formed in the drill bit body thus delimitating as many tapered drilling faces, each of them extending from the flat face of the leading end to the maximum diameter (Dmax). The flat face and the tapered drilling faces have a plurality of protruding teeth and the teeth are cylindrical and have a longitudinal axis (Y-Y) forming an angle with the face supporting the teeth which is less than or equal to 90.

A method of heating up a furnace bottom and a burner lance used in the method are proposed. The method of heating up the furnace bottom includes a step of opening, in the tap hole, a burner lance insertion hole having a diameter larger than a diameter of the burner lance so as to penetrate into the furnace, a step of installing the burner lance in the opened burner lance insertion hole, a step of filling a gap between the installed burner lance and a furnace exterior side of the tap hole with a refractory, and a step of blowing in gas for heating into the furnace from the burner lance to heat up the furnace bottom.