Method for refining sulfidic copper concentrate

Abstract

A method for refining sulfidic copper concentrate includes feeding sulfidic copper concentrate and oxygen-bearing reaction gas and slag forming material into a reaction shaft of a suspension smelting furnace, collecting slag and blister copper in a settler of the suspension smelting furnace to form a blister layer containing blister copper and a slag layer, and discharging slag and blister copper separately from the settler of the suspension smelting furnace, so that slag is fed into an electric furnace. The method further includes feeding a part of the sulfidic copper concentrate into the electric furnace.

Claims

1. A method for refining sulfidic copper concentrate, the method comprising: feeding a first portion of sulfidic copper concentrate and oxygen-bearing reaction gas and slag forming material into a reaction shaft of a suspension smelting furnace by means of a burner that is arranged on top of the reaction shaft of the suspension smelting furnace, whereby sulfidic copper concentrate and oxygen-bearing reaction gas and slag forming material react in the reaction shaft of the suspension smelting furnace into blister copper and slag; collecting slag and blister copper in a settler of the suspension smelting furnace to form a blister layer containing blister copper and a slag layer containing slag on top of the blister layer; discharging slag in an unreduced state and blister copper separately from the settler of the suspension smelting furnace, so that slag in an unreduced state is fed into an electric furnace; feeding a second portion of sulfidic copper concentrate into the electric furnace; reducing the slag that is fed in the unreduced state from the suspension smelting furnace in the electric furnace at least partly with the second portion of sulfidic copper concentrate that is fed into the electric furnace to form a matte layer containing copper matte and an electric furnace slag layer containing electric furnace slag on top of the matte layer; discharging electric furnace slag and matte copper separately from the electric furnace; granulating and treating the copper matte that is discharged from the electric furnace to obtain copper matte feed material; and feeding at least a part of the copper matte feed material into the reaction shaft of the suspension smelting furnace by means of the burner.

2. The method according to claim 1, further comprising: feeding blister copper from the settler of the suspension smelting furnace into an anode furnace; fire refining the blister copper in the anode furnace.

3. The method according to claim 1, further comprising: subjecting the electric furnace slag to a final slag treatment process to form reject and slag concentrate or other copper containing product; and feeding the slag concentrate or other copper containing product by means of the burner into the reaction shaft of the suspension smelting furnace.

4. The method according to claim 1, further comprising: feeding a carbon containing reducing agent into the electric furnace, wherein the carbon containing reducing agent is coke.

5. The method according to claim 1, further comprising: feeding process gases from an uptake of the suspension smelting furnace to a process gas treatment arrangement.

6. The method according to claim 1, further comprising: feeding process gases from the electric furnace to a process gas treatment arrangement.

7. The method according to claim 1, wherein the second portion of sulfidic copper concentrate that is fed into the electric furnace includes between 5 and 50% of the total amount of sulfidic copper concentrate, the total amount of sulfidic copper concentrate comprising the first and second portions of sulfidic copper concentrate.

8. The method according to claim 1, wherein the second portion of sulfidic copper concentrate that is fed into the electric furnace includes between 10 and 40% of the total amount of sulfidic copper concentrate, the total amount of sulfidic copper concentrate comprising the first and second portions of sulfidic copper concentrate.

9. The method according to claim 1, wherein the second portion of sulfidic copper concentrate that is fed into the electric furnace includes between 25 and 35% of the total amount of sulfidic copper concentrate, the total amount of sulfidic copper concentrate comprising the first and second portions of sulfidic copper concentrate.

10. The method according to claim 1, wherein the mass ratio of the second portion of the sulfidic copper concentrate that is fed into the electric furnace to slag that is fed into the electric furnace is smaller than 1 to 1.

11. The method according to claim 10, wherein the mass ratio of the second portion of the sulfidic copper concentrate that is fed into the electric furnace to slag that is fed into the electric furnace is between 0.25 to 1 and 0.7 to 1.

12. The method according to claim 10, wherein the mass ratio of the second portion of the sulfidic copper concentrate that is fed into the electric furnace to slag that is fed into the electric furnace is between 0.25 to 1 and 0.7 to 1.

13. The method according to claim 1, wherein the moisture content of the second portion of the sulfidic copper concentrate that is fed into the electric furnace is below 1% by weight.

14. The method according to claim 1, wherein the moisture content of the second portion of the sulfidic copper concentrate that is fed into the electric furnace is below 0.5% by weight.

15. The method according to claim 1, wherein the moisture content of the first portion of the sulfidic copper concentrate that is fed into the reaction shaft of the suspension smelting furnace is below 1% by weight.

16. The method according to claim 1, wherein the moisture content of the first portion of the sulfidic copper concentrate that is fed into the reaction shaft of the suspension smelting furnace is below 0.5% by weight.

17. The method according to claim 1, wherein the second portion of the sulfidic copper concentrate that is fed into the electric furnace includes about 33% of the total amount of sulfidic copper concentrate, the total amount of sulfidic copper concentrate comprising the first and second portions of sulfidic copper concentrate.

Description

LIST OF FIGURES

(1) In the following the invention will described in more detail by referring to the figures, which

(2) FIG. 1 shows a block diagram of a direct to blister process,

(3) FIG. 2 shows a block diagram of a first embodiment of the method, and

(4) FIG. 3 shows a block diagram of a second embodiment of the method.

DETAILED DESCRIPTION OF THE INVENTION

(5) FIG. 2 shows a block diagram of a first embodiment of the method for refining sulfidic copper concentrate 1 and FIG. 3 shows a block diagram of a second embodiment of the method for refining sulfidic copper concentrate 1.

(6) The method comprises feeding sulfidic copper concentrate 1 and oxygen-bearing reaction gas 2 and slag forming material 3 into a reaction shaft 4 of a suspension smelting furnace 5 by means of a burner 6 that is arranged on top of the reaction shaft 4 of the suspension smelting furnace 5, whereby sulfidic copper concentrate 1 and oxygen-bearing reaction gas 2 and slag forming material 3 react in the reaction shaft 4 of the suspension smelting furnace 5 into blister copper 8 and slag 7.

(7) The method comprises collecting slag 7 and blister copper 8 in a settler 9 of the suspension smelting furnace 5 to in the settler 9 of the suspension smelting furnace 5 form a blister layer 10 containing blister copper 8 and a slag layer 11 containing slag 7 on top of the blister layer 10.

(8) The method comprises discharging slag 7 in unreduced state and blister copper 8 separately from the settler 9 of the suspension smelting furnace 5, so that slag 7 in unreduced state is fed into an electric furnace 12.

(9) The method comprises feeding a part of the sulfidic copper concentrate 1 into the electric furnace 12.

(10) The method comprises reducing the slag 7, that is fed in unreduced state from the suspension smelting furnace 5, in the electric furnace 12 at least partly with the sulfidic copper concentrate 1 that is fed into the electric furnace 12 to in the electric furnace 12 form a matte layer 26 containing copper matte 27 and an electric furnace slag layer 20 containing electric furnace slag 21 on top of the matte layer 26.

(11) The method comprises discharging electric furnace slag 21 and matte copper separately from the electric furnace 12.

(12) The method comprises granulating and treating 28 the copper matte 27 that is discharged from the electric furnace 12 to obtain copper matte feed material 29.

(13) The method comprises feeding at least a part of said copper matte feed material 29 into the reaction shaft 4 of the suspension smelting furnace 5 by means of the burner 6.

(14) The method may include, as shown in FIGS. 2 and 3, feeding blister copper 8 from the settler 9 of the suspension smelting furnace 5 into an anode furnace 13 or into anode furnaces 13, and fire refining blister in the anode furnace(s) 13.

(15) The method may include, as shown in FIG. 2, subjecting the subjecting the electric furnace slag 21 to a final slag cleaning process 23 that can performed for example by flotation in a flotation arrangement (not shown in the figures) or in an additional electric furnace (not shown in the figures). From the final slag cleaning process 23 can slag concentrate or other copper containing product 25 be fed into the reaction shaft 4 of the suspension smelting furnace 5 by means of the burner 6 of the suspension smelting furnace 5 and reject 24 such as tailings be discarded.

(16) The method may include, as shown in FIG. 3, feeding additionally carbon containing reducing agent 17 such as coke into the electric furnace 12.

(17) The method may include, as shown in FIGS. 2 and 3, feeding process gases 16 from an uptake 14 of the suspension smelting furnace 5 to a process gas treatment arrangement 15.

(18) The method may include feeding process gases from the electric furnace 12 to a process gas treatment arrangement 15.

(19) The method may include feeding between 5 and 50%, preferably between 10 and 40%, more preferably between 25 and 35%, such as about 33%, of the sulfidic copper concentrate 1 into the electric furnace 12.

(20) The mass ratio of sulfidic copper concentrate 1 that is fed into the electric furnace 12 to slag 7 that is fed into the electric furnace 12 is preferably smaller than 1 to 1, more preferably between 0.25 to 1 and 0.7 to 1, even more preferably between 0.45 to 1 and 0.5 to 1.

(21) The moisture content of the sulfidic copper concentrate 1 that is fed into the electric furnace 12 is preferably below 1%, more preferably below 0.5% by weight.

(22) The moisture content of the sulfidic copper concentrate 1 that is fed into the reaction shaft 4 of the suspension smelting furnace 5 is preferably below 1%, more preferably below 0.5% by weight.

Example 1

(23) 70% of the sulfidic copper concentrate (containing in percentages mass 25% Cu) was fed into the suspension smelting furnace at a feeding rate of 76 t/h and 30% of the sulfidic copper concentrate (containing in percentages mass 25% Cu) was fed into the electric furnace at a feeding rate of 33 t/h. From the suspension smelting furnace was discharged blister copper (containing in percentages mass 98.4% Cu) at a discharge rate of 26 t/h and slag containing in percentages mass 24% Cu at a rate of 73 t/h into the electric furnace. From the electric furnace was discharged copper matte (containing in percentages mass 65% Cu) at a rate of 37 t/h and electric furnace slag (containing in percentages mass 2% Cu) at a rate of 65 t/h into a slag cleaning process including slag flotation. The copper matte discharged from the electric furnace was granulated, grinded and fed into the suspension smelting furnace. From the slag cleaning process was slag concentrate (containing in percentages mass 20% Cu) recycled into the suspension smelting furnace at a feed rate of 5 t/h and tailings (containing in percentages mass 0.5% Cu) was discharged.

Example 2

(24) 65% of the sulfidic copper concentrate (containing in percentages mass 25% Cu) was fed into the suspension smelting furnace at a feeding rate of 70 t/h and 35% of the sulfidic copper concentrate (containing in percentages mass 25% Cu) was fed into the electric furnace at a feeding rate of 42 t/h. From the suspension smelting furnace was discharged blister copper (containing in percentages mass 98.4% Cu) at a discharge rate of 26 t/h and slag containing in percentages mass 24% Cu at a rate of 83 t/h into the electric furnace. Reducing agent in the form of Coke was also fed into the electric furnace at a feeding rate of 2 t/h. From the electric furnace was discharged copper matte (containing in percentages mass 55% Cu) at a rate of 51 t/h and electric furnace slag (containing in percentages mass <1% Cu) at a rate of 70 t/h. The copper matte discharged from the electric furnace was granulated, grinded and fed into the suspension smelting furnace.

(25) It is apparent to a person skilled in the art that as technology advances, the basic idea of the invention can be implemented in various ways. The invention and its embodiments are therefore not restricted to the above examples, but they may vary within the scope of the claims.