US 6,630,099 B2 · Continuous metal melting apparatus

Abstract

A rotary furnace apparatus is provided for rapid melting of a variety of virgin and recycled ferrous and non-ferrous metals, which distributes the introduction of the unmelted charge materials and hence the melting heat requirements along an elongate gas-solid-liquid reaction zone within the furnace, according to the distribution of heat available to effect melting. In the case of fine-sized metal charge materials, fluxes and additive reagents, a longitudinally traversing solids injection lance projecting into the furnace is provided with nozzle directed to project a jet of charge down into the bath as it traverses successively backwards and forwards. A traversing oscillating conveyor is provided for coarse-sized scrap metals and the like. A preferred embodiment includes longitudinal extension of the furnace to include a gas-liquid reaction zone adapted for conducting refining reactions and adjusting metal temperature prior to discharging, as heated by a burner generating hot furnace gases which flow countercurrent to the general metal movement. The discharge of liquid metal and slag can be via tap hole, vacuum siphon or overflowing the annular lip of the discharge opening. Burner and lance apparatus adapted for direct introduction of heat along the gas-solid-liquid reaction zone and also oxygen for effecting combustion of furnace gases to CO2 and H2O before exhausting from the furnace are preferred features. A duct system adapted for recirculating a major portion of the exhaust gases into the furnace is optionally included.

Claims18

Dependent claims

An apparatus for conducting the process of continuous melting of solid charge materials comprising an elongate rotary fu ace having horizontal longitudinal disposition and annular end openings adapted for containing a partially melted bath of charge materials in a gas-solid-liquid reaction zone heated by a hot gas stream passing over said bath, characterized by the combination of:

means for maintaining a gas-solid liquid reaction zone within said furnace adapted for containing a partially melted bath heated by a hot gas stream passing over said bath;
means for conveying solid charge materials through at least one of said end openings into said hot gas stream and along said gas solid-liquid reaction zone and downwardly projecting said charge materials directly into said bath;
means for continually traversing aid means for said conveying and downwardly projecting said charge materials successively backwards and forwards adapted for longitudinally distributing the entry location of aid charge materials directly into said bath along a longitudinal traverse span of said gas-solid-liquid reaction zone;
and
means for liquid metal exit allowing liquid metal to flow out of said gas-solid-liquid reaction zone adapted to provide for replenishing said bath by said solid charge materials.

2 more elements

at least one pneumatic solids injection lance cantilevered longitudinally into said hot gas stream along said gas-solid-liquid reaction zone with an exit nozzle of said lance directed downwardly adapted for injecting said solid charge materials into said partially melted metal bath;
means for stroking said lance successively backwards and forwards, adapted for continually distributing the entry location of aid solid charge materials along a longitudinal traverse span of said gas-solid-liquid reaction zone;
and
means for exit allowing liquid charge materials to flow out of said gas-solid-liquid reaction zone adapted to provide for replenishing said bath by said solid charge materials.

1 more element

An apparatus for conducting he process of continuous melting of solid charge materials comprising an elongate rotary furnace having horizontal longitudinal disposition and annular end openings adapted for containing a partially melted bath of charge materials in a gas-solid-liquid reaction zone heated by a hot gas stream passing over said bath, characterized by the combination of:

at least one pneumatic solids injection lance cantilevered longitudinally into said hot gas stream along said gas-solid-liquid reaction zone with an exit nozzle of said lance directed downwardly adapted for injection a portion of said solid charge materials into said partially melted metal bath;
a reversing lance drive adapted f r stroking said lance successively backwards and forwards along a lance-fed portion of a longitudinal traverse span within said gas-solid-liquid reaction zone;
an oscillating conveyor cantilever d longitudinally into said hot gas stream along said gas-solid-liquid reaction zone with a discharge lip of said conveyor adapted for dropping another portion of said solid charge materials downwards into said partially melted metal bath;
a reversing conveyor drive adapted for stroking said oscillating conveyor successively backwards and forwards along a conveyor-fed portion of said longitudinal traverse span within said gas-solid-liquid reaction zone;
and
means for exit allowing liquid charge materials to flow out of said gas-solid-liquid reaction zone adapted to provide for replenishing said bath by said solid charge materials.

3 more elements

An apparatus for conducting the process of continuous melting of charge materials comprising an elongate rotary furnace having horizontal longitudinal disposition and annular end openings adapted for containing a partially melted bath or charge materials in a gas-solid-liquid reaction zone heated by a hot gas stream passing over said bath, characterized by the combination of:

means for maintaining a gas-liquid reaction zone carrying substantially only hot liquid charge materials and slag adjacent to said gas-solid-liquid reaction zone within said rotary furnace;
an annular dam proximate the junction between said gas-solid-liquid and gas-liquid reaction zones which extends radially inwards from the furnace side walls to an annular dam crest with an invert at a level higher than the surface of the layer of slag during the full rotation of said rotary furnace, thereby being adapted to obstruct the longitudinal transfer of slag between said two zones;
at least one channel communicating longitudinally through said dam with a channel entrance opening out of said gas-solid-liquid reaction zone and a channel exit opening into said gas-liquid reaction zone, adapted to allow said exit of liquid charge material from said gas-solid-liquid reaction zone and transfer into said gas-liquid reaction zone.

An apparatus for conducting the process of continuous melting of solid charge materials comprising an elongate rotary furnace having horizontal longitudinal disposition and an annular charge end and a discharge end opening adapted for containing a partially melted bath of charge materials in a gas-solid-liquid reaction zone heated by a hot gas stream passing over said bath in the general direction from said discharge end to charge end characterized by the combination of:

means for maintaining a gas-liquid reaction zone carrying substantially only hot liquid charge materials and slag adjacent to said gas-solid-liquid reaction zone within said rotary furnace;
an annular dam proximate the junction between said gas-solid-liquid and gas-liquid reaction zones restricting rate of charge flow but adapted to allow exit of hot liquid charge materials from said gas-solid-liquid into said gas-liquid reaction zone;
at least one pneumatic solids injection lance cantilevered longitudinally into said hot gas stream along said gas-solid-liquid reaction zone with an exit nozzle of said lance directed downwardly adapted for injecting said solid charge materials into said partially melted metal bath;
means for stroking said lance successively backwards and forwards, adapted longitudinally distributing the entry location of said charge materials into said bath along a longitudinal traverse span of said gas-solid-liquid reaction zone;
an off-gas collecting duct communicating with said charge end opening adapted to receive hot off-gases contained in said hot gas stream and exhaust a portion thereof;
and
an off-gas recirculation duct connecting into said collecting duct adapted to receive a portion of the hot off-gases, including means for propelling, transferring and directing said portion of hot off-gases through said discharge end opening into said hot gas stream within said rotary furnace adapted to recover off-gas heat from said off-gases in combination with lowering the maximum hot gas temperatures within said hot gas stream;
a burner proximate said discharge end opening emitting combustion products directed to mix with said recirculated portion of hot off-gases;
and
means for discharging said hot liquid charge from said gas-liquid reaction zone.

7 more elements

Dependencies are inferred from the claim text.

Continuous metal melting apparatus

Life of this patent

Continuous metal melting apparatus

Life of this patent

Abstract

Claims18