Starting a smelting process

Patent metadata

Field	Value
Publication number	US-2015259758-A1
Application number	US-201314416378-A
Country	US
Kind code	A1
Filing date	Jul 18, 2013
Priority date	Jul 25, 2012
Publication date	Sep 17, 2015
Grant date	—

Abstract

A method of starting a molten bath-based process for smelting a metalliferous material is disclosed. The method includes using the heat flux of water-cooled elements in lower parts of a smelting vessel to provide an indication of molten bath temperature during at least an early part of the start-up method and adjusting injection rates of oxygen-containing gas and/or carbonaceous material into the smelting vessel to control the molten bath temperature during start-up without exceeding critical heat flux levels and tripping the start-up method.

First claim

1 . A method of starting a molten bath-based smelting process for a metalliferous material in a smelting vessel that defines a smelting chamber and producing molten metal, with the method including supplying a charge of hot metal into the smelting chamber, supplying feed materials into the smelting chamber and generating heat and forming molten slag and thereafter increasing the amount of molten slag in the smelting chamber, with the hot metal and the molten slag forming a molten bath in the smelting chamber, monitoring the heat flux of a side wall of the vessel in contact with the molten bath to obtain an indication of the temperature in the molten bath as the amount of slag increases towards the suitable slag inventory, and adjusting the supply rates of solid carbonaceous material and/or oxygen-containing gas into the smelting chamber to adjust the heat input into the smelting chamber and thereby control the temperature of the molten bath so that the bath temperature does not cause high heat fluxes in the side wall that trip the start-up sequence of the smelting process.

2 . A method of starting a molten bath-based process for smelting a metalliferous material in a smelting vessel and producing molten metal, the smelting vessel including (a) an initially empty smelting chamber having a hearth and a side wall extending upwardly from the hearth, with the side wall including water-cooled elements at least in a lower section of the side wall, (b) a forehearth, and (c) a forehearth connection that interconnects the smelting chamber and the forehearth, with the method including the steps of:
(a) supplying a charge of hot metal into the smelting chamber via the forehearth; (b) supplying a solid carbonaceous material and an oxygen-containing gas into the smelting chamber after completing the hot metal charge and igniting the carbonaceous material and heating the smelting chamber and hot metal and forming molten slag and thereafter increasing the amount of molten slag, with the hot metal and the molten slag forming a molten bath in the smelting chamber; (c) supplying a metalliferous material into the molten bath and smelting metalliferous material to molten metal;
and wherein, during step (b), the method including controlling the temperature in the molten bath by:
(i) monitoring the heat flux of water-cooled elements in contact with the molten bath to obtain an indication of the temperature in the molten bath,
(ii) adjusting the supply rates of the solid carbonaceous material and/or the oxygen-containing gas having regard to water-cooled element heat flux to adjust the heat input into the smelting chamber and thereby control the temperature of the molten bath so that the bath temperature does not cause high heat fluxes in the water-cooled elements that trip the start-up sequence of the smelting process.

3 . The method defined in claim 2 includes preheating the smelting chamber, the forehearth, and the forehearth connection.

4 . The method defined in claim 2 includes preheating a hearth of the vessel, the forehearth, and the forehearth connection such that an average surface temperature of the hearth, the forehearth, and the forehearth connection is above 1000° C.

5 . The method defined in claim 2 includes preheating a hearth of the vessel, the forehearth, and the forehearth connection such that an average surface temperature of the hearth, the forehearth, and the forehearth connection is above 1200° C.

6 . The method defined in claim 2 wherein step (a) includes supplying sufficient hot metal so that the level of the hot metal is at least about 100 mm above the top of the forehearth connection.

7 . The method defined in claim 1 includes injecting a gas or liquid fuel and an oxygen-containing gas into the gas space above the metal for a period of time after completing the hot metal charge into the smelting chamber to generate heat in the smelting chamber.

8 . The method defined in claim 2 wherein step (b) includes supplying flux material into the smelting chamber to promote molten slag formation.

9 . The method defined in claim 2 includes injecting slag or slag-forming agents such as silica sand/bauxite plus lime/dolomite flux to promote molten slag formation in the molten bath.

10 . The method defined in claim 2 includes commencing step (c) of supplying the metalliferous material into the molten bath at any time during the course of step (b).

11 . The method defined in claim 2 wherein the molten bath-based smelting process includes the steps of:
(a) supplying carbonaceous material and solid or molten metalliferous material into the molten bath and generating reaction gas and smelting metalliferous material and producing molten metal in the bath,
(b) supplying oxygen-containing gas into the smelting chamber for above-bath combustion of combustible gas released from the bath and generating heat for in-bath smelting reactions; and
(c) producing significant upward movement of molten material from the bath by gas upwelling in order to create heat-carrying droplets and splashes of molten material which are heated when projected into the combustion region in the top space of the smelting chamber and thereafter fall back into the bath, whereby the droplets and splashes carry heat downwards into the bath where it is used for smelting of the metalliferous material.

12 . A method of starting a molten bath-based process for smelting a metalliferous material including using heat flux of water-cooled elements in lower parts of a smelting vessel to provide an indication of molten bath temperature during at least an early part of the start-up method and adjusting injection rates of oxygen-containing gas and/or carbonaceous material into the smelting vessel to control the molten bath temperature during start-up to avoid exceeding critical heat flux levels and tripping the start-up method.

13 . The method defined in claim 1 includes injecting a gas or liquid fuel and an oxygen-containing gas into the gas space above the metal for a period of time after completing the hot metal charge into the smelting chamber to generate heat in the smelting chamber.

14 . The method defined in claim 1 includes injecting slag or slag-forming agents such as silica sand/bauxite plus lime/dolomite flux to promote molten slag formation in the molten bath.

15 . The method defined in claim 1 wherein the molten bath-based smelting process includes the steps of:
(a) supplying carbonaceous material and solid or molten metalliferous material into the molten bath and generating reaction gas and smelting metalliferous material and producing molten metal in the bath,
(b) supplying oxygen-containing gas into the smelting chamber for above-bath combustion of combustible gas released from the bath and generating heat for in-bath smelting reactions; and
(c) producing significant upward movement of molten material from the bath by gas upwelling in order to create heat-carrying droplets and splashes of molten material which are heated when projected into the combustion region in the top space of the smelting chamber and thereafter fall back into the bath, whereby the droplets and splashes carry heat downwards into the bath where it is used for smelting of the metalliferous material.

Assignees

• Tech Resources Pty Ltd

Inventors

• Mccarthy Carolyn
• Dry Rodney James

Classifications

• C21B13/0013 Primary

  introduction of iron oxide into a bath of molten iron containing a carbon reductant · CPC title

• C21C5/567 Primary

  operating in a continuous way · CPC title

• C21C5/305

  Afterburning · CPC title

• C21C2200/00

  Recycling of waste material · CPC title

• F27B3/24

  Cooling arrangements · CPC title