FI115536B - A process for producing crude copper - Google Patents

Description

I 1 115536

METHOD FOR PREPARING COPPER COPPER

The present invention relates to a pyrometallurgical process for the production of crude copper in a smelting reactor, such as a slurry furnace, directly from copper sulphide concentrate and / or finely ground copper rock.

The prior art process is to produce crude copper or blister from sulfide concentrate in several steps where the concentrate is smelted in a slurry reactor, such as a slurry furnace, with air or oxygen enriched air 10 to give a highly copper-rich copper rock containing 50-75% copper and slag. Such a process is described, for example, in U.S. Patent No. 250,657. The copper formed in the slurry furnace is converted, for example, in a Pierce-Smith type converter into raw copper, which is further refined in an anode furnace.

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Production of crude copper directly from a sulphide concentrate in one process step in a slurry reactor is economically viable under certain boundary conditions. The main problems directly related to the production of raw copper are the loss of copper ... and the large amount of slag formed. A large amount of slag requires> 20 new process steps to recover copper, which has an impact on the economic viability of the process.

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If the copper content of the concentrate is high enough, typically at least 37% by weight of copper, as in the case of the Olympic Dam smelter in Australia 25 where the copper content of the concentrate is normally above 40% by weight, it is economically feasible to produce crude copper directly. When using the above concentrate, the amount of slag is reasonable, but in order to: make low-sulfur copper having a low sulfur content of less than 1. sulfur by weight, the oxidation conditions must be selected so that the slag produced contains 15-25% by weight of copper.

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A low copper concentrate may also be suitable for the production of crude copper if its composition is advantageous. For example, in the Glogow smelter in Poland, raw copper is produced from concentrate in a single step because of the low iron content and the significant amount of slag formed. Copper production from normal concentrates in one step results in the slagging of all iron and other siding. Such a method is described in U.S. Patent 4,030,915.

Fl patent 104838 describes a process for the production of crude copper in a slurry reactor directly from a sulfide copper concentrate, wherein the concentrate, slag former and oxygen enriched air are fed to the reactor. The cooled and finely ground copper rock is fed to the slurry reactor together with the concentrate to capture the heat released from the concentrate and reduce the relative amount of slag, whereby the oxygen supply to the reactor is at least 50% oxygen.

However, said Fl patent 104838 limits the process to areas where the oxygen enrichment is higher than 50% oxygen and, on the other hand, the concentrate quality is limited to a concentration of more than 31% copper in the concentrate. In this patent, depending on the nature of the concentrate, the limit is to use both iron silicate slag «4 ·« (substantially free of calcium oxide) and calcium ferrite slag (substantially *; · · · free of silicates).

* · ♦ 11 PCT Publication No. WO 00/09772 describes a process for depleting copper sulphide concentrate by oxygen smelting followed by removal of most of the iron in the copper sulphide concentrate and removal of some or most of the sulfur in the concentrate. -; bond SO2, wherein the copper from the sulfide concentrate is either so-called. white metal, almost white metal or copper. The process of smelting with oxygen, 30 produces slag with a CaO / (SiO 2 + CaO) weight ratio of 0.3 to 0.6 (CaO / SiO 2 = 0.43 to 1.5), and Fe / (FeOx + The Si02 + CaO) weight ratio is in the range of 0.2 to 0.5, and and white metal, near white metal or crude copper, by adding 3,115,536 to SiO2 and CaO as a slag former in the copper sulphide concentrate. The object of the patent described in PCT Publication WO 00/09772 is a process for smelting copper sulphide concentrate for the continuous production of white metal or crude copper by oxidation of copper sulphide concentrate or stone at 1300 ° C or less, without magnetite interference, suitable for treating the losses of the slag are reduced and the copper contained in the slag is recovered by foaming; arsenic, antimony and lead are largely eliminated in the slag and the corrosion of the fire surfaces is reduced.

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However, said PCT patent application WO 00/09772 limits the process slag composition area to a window having a CaO / SiO 2 ratio in the slag of less than 1.5 and a relatively high silica content in the slag of at least about 12.4% SiO 2 in pure CaO-S 1 O 2 -FeOx 15 (CaO = 18.6%). As the limestone content increases in the slag, the silica content must also be increased and the total amount of slag increased accordingly. For example, when the CaO / (CaO + SiO 2) ratio is 0.6, and the Fe / (CaO + SiO 2 + FeOx) ratio drops from 0.5 to 0.2, the amount of slag more than doubles. The biggest. '; ·. The CaO / SiO 2 ratio is 1.5.

• 1 ·: V: 20; It is an object of the present invention to eliminate the disadvantages of the prior art and to provide an improved process for the production of crude copper or copper fines directly from sulphide concentrate and / or finely ground copper stone, in which both silica (SiO2) and limestone are fed to the process. (CaO) -containing substances to form a slag having a fluid temperature range of 1250 to 1350 ° C. The essential inventive features of the invention are set forth in the appended claims.

*, 30 According to the method, a slurry reactor, such as a slurry furnace, is fed with copper sulphide concentrate and / or copper shale together with oxygen gas; the furnace is also fed with materials containing both silica (S1O2) and limestone 4115536 (CaO) to form a slag with a Ca0 / SiO2 ratio greater than 1.5 and a fluid temperature in the range of 1250 to 1350 ° C. for slag flow, the slag additionally contains at least 6% by weight of oxidized copper.

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The process according to the invention is based on the fact that the slag oxidized copper effectively forms slag from both magnetite and dicalcium silicate, which in turn limits the suitability of CaO-SiO 2 -FeOx slag for copper smelting. Under oxidation conditions where the copper sulfur content is less than 0.8 wt% -10%, some of the copper in the concentrate and / or finely ground stone is oxidized, causing a slag effect that allows the operating window to be expanded - i.e., eliminates the CaO / (CaO + Si02) limitation = 0.3-0.6 and Fe / (CaO + SiO 2 + FeOx) = 0.2-0.5 as defined by the method of PCT patent application WO 00/09772 described above. 15

In the process according to the invention, raw copper or fine fine stone is prepared in a slurry reactor from a mixture containing copper concentrate and / or rock and silicate and limestone-containing material. Chilled and finely chopped ·; *. the ground copper rock is fed to the suspension reactor in the form of such crude copper 20 with a sulfur content of less than 1.0% by weight, with a relatively low slag * I tf; Y: activity, with a high limestone activity, thus improving arsenic and antimony slagging while silica active - •: · i high to eliminate lead from crude copper.

The finely milled rock fed into the raw copper furnace can be derived from any known furnace having a copper content of 60 to 78% by weight.

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A single suspension smelting unit can be designed directly as a crude copper smelter depending on the copper content and composition of available concentrates and the amount of finely ground stone.

Γ ": 30 Ί.: The slag is further processed in a one-step or preferably two-step slag purification process.

If the production of copper stone is carried out in a flame smelting furnace, the slag from the smelting step of the raw copper can advantageously be granulated and fed to the primary smelting furnace to recover the copper. The economics of the process depend on the amount of concentrate in the feed mixture and the amount of slag produced. From the primary smelting furnace, the slag goes to normal single-stage cleaning or direct removal (electric furnace, slag cleaning furnace or slag flotation) depending on the copper content of the slag.

The invention will be further described with reference to the following example and the accompanying drawings, in which Figure 1 shows the copper contents of various slag types as a function of the normalized partial oxygen pressure (T = 1300 ° C) in the crude copper of Example 1,

Figure 2 shows the partition coefficient of arsenic between slag and crude copper as a function of normalized partial pressure of oxygen in the crude copper according to Example 1,: Figure 4 shows the copper content of the slag according to Example 1 FeOx + CaO +:] t '': S1O2 = 100 in the diagram, Figure 5 shows the partition coefficient of arsenic between slag and raw copper according to Example 1 FeOx + CaO + S1O2 = 100 in the graph normalized • · * such that (Cu%) in the slag = 20%, Figure 6 shows the distribution coefficient for lead between the slag and the copper in accordance with Example 1, FeOx + CaO + SiO2 = 100 in the graph. · *. 30 such that (Cu%) in the slag = 20%, and • I> • «* * ·

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6, 115536

Figure 7 shows the viscosity temperature of the slag at 200 cP according to Example 1 in the diagram of FeOx + CaO + S1O2 = 100 normalized to (Cu%) in the slag = 15%.

Example 1

Crude copper was prepared in a minipilot suspension smelting furnace in a series of experiments in which the copper-containing raw materials were finely ground copper rock (72.3 wt% Cu, 3.4 wt% Fe, 20.3 wt% S) and copper rich 10 te (29.2 wt% Cu, 33, 7 wt% S, 21.0 wt% Fe). The mixture of copper stone and concentrate (kg stone) / (kg stone + kg concentrate) * 100 ranged from 50 to 100%. The feed rate was 100-200 kg / h. The degree of oxidation of the crude copper obtained was controlled by the oxygen coefficient (Nm3 (Wt of feed) and the slag composition (CaO / SiO2, Fe / Si (> 2 in the slag)) was controlled by the addition of silica sand and limestone to the feed. as standard, slag and crude copper were removed from the bottom furnace of the minipilot and the resulting crude copper and slag analyzed for an average sulfur content of 0.2 wt% sulfur (0.01 to 0.89 wt% sulfur).

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The following is an example of one test cycle test results: ·: ··: Rock feed rate 89.7 kg / h

Rock Quality (3.4% Fe, 18.2% S, 0.26% As, 0.2% Pb) 72.3% Cu 25 Concentrate Feed Rate 59.9 kg / h

Quality of concentrate (20.9% Fe, 30.7% S, 5.1% S1O2,: ": 1.3% As, 0.11% Pb) 30.2% Cu: Silica sand feed rate 0.5 kg / h

Flow rate of limestone 10.3 kg / h ·· *. 30 Technical oxygen delivery rate to concentrate burner 29.0 Nm3 / h

The air supply rate to the concentrate burner is 31.0 Nm3 / h

Oxygen Enrichment 59.2% 115536 7

Oxygen factor 245.4 Nm302 ^

Feed of butane to the reaction shaft and lower furnace to balance heat loss 3.03 kg / h

Test duration (input) 3h 10 min

5 Discharge temperature 1300 ° C

Quality of the raw copper produced:

Sulfur content 0.08% S

Arsenic content 0.077% As 10 Lead content 0.035% Pb

Quality of the slag produced:

The copper content is 18.3% Cu

Limestone content 19.3% CaO

15 Silica content 7.6% S1O2

Iron content 28.2% Fe

Arsenic content 0.68% As

Lead content 0,28% Pb | . ·. CaO / SiO 2 (% w / w) 2.54 µ 20 Fe / SiC> 2 (% w / w) 3.71: V: CaO / (CaO + S 1 O 2) (% w / w) %) 0.72 ·: **: Partition coefficient for arsenic between slag and crude copper 8.8 •: *: Partition coefficient for lead between slag and crude copper 8.0 «· • ·> 25 The applicability of the method is explained in more detail by reference to experimental results and Figures 1. -7.

»4 *» · i: Figure 1 shows the copper contents of various slag types as a function of the normalized partial pressure of oxygen (T = 1300 ° C) in crude copper. The figure shows that as the CaO / SiO 2 ratio (at a given Fe / SiO 2 ratio) increases, the copper content of the slag decreases. For comparison purposes, Fig. 1 also shows the copper content of faience slag (ferrous silicon slag). Compared to FA, the concentration of copper at the same oxygen potential is much lower.

Figure 2 shows the partition coefficient of arsenic between slag and crude copper for 5 LAs (slag / Cu> = (% As in slag) / (% As in crude copper) for various slag types as a function of normalized oxygen partial pressure in crude copper. / SiO 2 ratio) increases, the arsenic and bulk partition coefficient, LAs (slag / Cu), increases. The coefficient of the / SiO 2 slag at the same oxygen potential shows a significantly better ability to remove arsenic from crude copper.

Figure 3 shows the partition coefficient for lead between slag and crude copper as 15 Lpb (slag / Cu) = (% pe in slag) / (% Pb in crude copper) for various slag types as a function of normalized oxygen partial pressure in crude copper. The figure shows that as the slag CaO / SiO 2 ratio (at a given Fe / SiCl 2 ratio) increases, the lead partition coefficient,? _Pb <slag / Cu> i, slightly decreases. By way of comparison, Figure 3 also shows the partition coefficient for lead in the middle 20 of calcium ferrite slag and crude copper. Compared to the partition coefficient Lpb (slag / Cu) of lead calcium ferrite slag,: ':': the coefficient of CaO / SiO 2 slag is higher at the same oxygen potential and shows': ·: its significantly better ability to remove arsenic from crude copper.

Figure 4 shows the copper content of the slag FeOx + CaO + S1O2 = 100 diagram-25. The results are normalized to 1300 ° C and partial oxygen pressure: * log PO 2 = -4.5. The figure shows that when operating with a combination of FeOx +: CaO + SiO2 + copper oxide slag and a constant oxygen partial pressure, the copper content of the slag is between 10-20% when the CaO / SiO2 ratio is greater than 1.5 and, ' The CaO content of the Ca0 + SiO2 + Fe0x system is higher than 20%.

Figure 5 shows the partition coefficient for arsenic between slag and crude copper in a graph of FeOx + CaO + S1O2 = 100, normalized to (Cu%) 9115536 in slag = 20%. Distribution lines based on test results are also marked on the drawing. When the CaO / SiO 2 ratio is greater than 1.5, the partition coefficient increases as the CaO concentration in the system increases.

Figure 6 shows the distribution coefficient for lead between slag and crude copper in the graph of FeOx + CaO + SiO2 = 100, normalized to (Cu%) in the slag = 20%. When the CaO / SiO 2 ratio is greater than 1.5, the partition coefficient for lead increases as the CaO content in the system decreases.

10 In the pilot tests, the viscosity of the slag was low enough to allow the slag to be discharged from the furnace through a normal outlet. To further investigate the viscosity behavior of the slags, some of the slags obtained from the pilot tests were subjected to viscosity measurements. Fig. 7 is a graph showing a viscosity of 200 cP for a given slag of FeOx + CaO + SiO2 = 100, normalized to (Cu%) in the slag = 15%. The temperature corresponding to a viscosity of 200 cP increases as the CaO content of the slag decreases. According to theoretical calculations, the formation of solid magnetite limits the use of such slag, as indicated by the dotted line in Figure 7.

t I | The results of Figures 1-7 show that the slag is sufficiently fluid to be removed from the furnace when the slag CaO / SiO 2 ratio is greater than 1.5, and when: FeOx + CaO + SiO 2 = 100 calculated slag CaO content higher ·: ·: than 20% and when slag copper content higher than 8% Cu in slag.

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Claims (5)

A process for producing blister copper or copper concentration pebbles in a suspension melting furnace directly from sulphidic material containing copper concentrate and / or from finely ground copper stone, in which process containing oxygen, copper concentrate and / or finely ground copper stone is fed into a reactor, characterized by flux containing CaO and SiO2 is fed into the melt reactor together with gas containing oxygen, copper concentrate and / or copper stone and some of the copper contained in the concentrate and / stone is oxidized to produce a slag in which the CaO / SiO2 ratio is higher than 1 And in which the copper content is in oxidic form and in which the lime content calculated in a CaO + SiO2 + FeOx = 100 system is higher than 20%. Process according to claim 1, characterized in that the copper content of the slag in oxidized form is at least 6% by weight. Process according to claim 1 or 2, characterized in that the activity of lime in the slag formed is high for increasing the slagging of arsenic and antimony. * 1 · 20 Method according to claim 1 or 2, characterized in that the activity of silica in the formed slag is high in order to eliminate lead from the blister copper. _,. Process according to any of the preceding claims, characterized in that the process is carried out in a melting unit by using gas containing •; 25 acid. »· ·