TH36702B - Direct smelting process - Google Patents

Abstract

DC60 (18/03/45) Direct melting process and fixed, non-rotating metal vessel for the production of metal from phosphorus metal feed material. The process is disclosed as a process that uses a molten bath which involves the injection of a solid feed material along with a carrier gas into the molten bath through one or more lance/openings (11) protruding downwards and causing a gas flow from the molten bath at a minimum flow rate of 0.30 Nm3/S/m2 at the surface between the layer of metal (15) and the molten metal residue layer (16) of the molten bath (under calm conditions). Direct melting process and fixed, non-rotating metal vessel for the production of metal from phosphorus metal feed material. The process is disclosed as a process that uses a molten bath which involves the tearing of a solid feed material along with a carrier gas into the molten bath through one or more lance/openings (II) protruding downwards and causing a gas flow from the molten bath. At the lowest flow rate of 0.30 Nm3/S/m2 at the surface between the metal layer (15) and the molten metal residue layer (16) of the molten pool (under calm conditions).

Claims (16)

1. Direct melting process for producing phosphorus metal feedstock in a stationary, non-rotating metal vessel. The process includes the following steps: (a) formation of a molten pool with a layer of metal and a slag layer on top of the metal layer in the vessel; (b) injection of the phosphorus metal feedstock and/or solid carbon-containing material along with carrier gas into the molten pool through one or more downward-facing lances/openings, and smelting of the ferrous metal onto the metal in the molten pool. The injection of solids and gas creates a gas flow from the molten pool at a minimum flow rate of 0.30 Nm3/S/m2 at the interface between the metal layer and the slag layer (under quiescent conditions), where the gas flow carries the molten material in the molten pool upwards in streams, droplets, and flows, creating a transition zone in the continuous gas void in the vessel above the slag layer. (c) The injection of oxygen-containing gas into the container through one or more lances/openings, and the release of post-combustion reactive gases from the molten bath, where the rising and falling streams of molten metal facilitate heat transfer to the molten bath, and where the transition zone minimizes radioactive heat loss from the container through the side walls exposed to the transition zone. 2. The process defined in Claim 1 involves melting metallic materials into a new metal, primarily within a metallic layer. 3. The process defined in Reputation 1 or Reputation 2, in which the injection of solids and gases in step (b) causes a massive flow of gas from the molten pool across the surface between the layer of molten metal and the layer of molten residue (under calm conditions). 4. A process defined in one of the preceding claims at a minimum gas flow rate of 0.35 Nm3/S/m2 at the interface between the metal layer and the molten metal residue layer (under calm conditions). 5. A process defined in one of the preceding claims where the gas flow rate is less than 0.50 Nm3/S/m2 at the interface between the molten metal layer and the slag layer (under calm conditions). 6. The process defined in one of the preceding claims, where the transition zone extends above the molten metal residue layer. 7. A process defined in one of the preceding claims, where a layer of dissolved carbon in the metal is greater than 4 wt%. 8. A process defined in one of the preceding claims where the concentration of ferrous oxide (Fe₂O₃) in the molten metal residue is less than 5 wt%. 9. The process defined in one of the preceding claims also includes the selection of an amount of solid carbon-containing material to be injected into the molten bath in excess of that required for melting the phosphorus feedstock and for heating to maintain the reaction rate, whereby the powder to be removed in a non-gaseous state while exiting the container will contain at least some excess carbon. 10. The process defined in claim 9 results in a concentration of solid carbon in the non-gaseous dust from the container ranging from 5 to 90 wt% (with a more optimal range of 20 to 50 wt%) of the weight of the non-gaseous dust at a dusting rate of 10-50 g/Nm3 in the non-gaseous state. 11. The process defined in any of the preceding claims in which the injection of metallic and carbon-containing materials in step (b) occurs through the same lance/opening or separate lance/opening. 12. The process defined in any of the preceding claims in which a gas containing oxygen is oxygen, air, or oxygen-rich air containing at least 40% oxygen by volume. 13. The process defined in any of the preceding claims, where step (c) operates at an advanced level, is at least 40% of the post-combustion state, where the post-combustion state is defined as: [CO2]+[H2O] [CO2]+ [H2O]+[CO]+[H2], where: [CO2] = volume as % of CO2 in the non-gaseous state, [H2O] = volume as % of H2O in the non-gaseous state, [CO] = volume as % of CO in the non-gaseous state, and [H2] = volume as % of H2 in the non-gaseous state. 14. The process defined in any of the preceding claims where step (b) includes the injection of solids and gases into the molten bath through one or more lances/openings protruding along the side walls of the vessel and angled downward and inward toward the layers of metal. 15. The process defined in one of the preceding claims, where step (c) involves the injection of oxygen-containing gas into the vessel through one or more lances/openings so that (a) the oxygen-containing gas is injected toward and through the transition zone; (b) the transition zone extends upwards around the bottom of each lance/opening to some degree; and (c) there is a continuous gaseous space, called the "free space," which is free of any metal and debris around the ends of each lance/opening. 16. The process defined in claim 9 where the concentration of solid carbon in the non-gaseous dust from the container is in the range of 20 to 50 wt% of the weight of the non-gaseous dust at a dusting rate of 10-50 g/Nm³ in the non-gaseous state.