WO2004046401A1 - Method for obtaining copper by spraying a melt containing a copper raw material - Google Patents

Abstract

The invention relates to a method for obtaining copper from highly concentrated black copper or copper metal or matte from copper smelting and/or nickel smelting. According to said method, a highly concentrated, black copper and/or copper metal melted mass is ejected and sprayed through an outlet (4) in the bottom of a tundisch (1) by means of an inert gas or oxidising gases, as the envelope of a gas jet. Said inert gases or oxidising gases are introduced into the melted mass by means of a lance (6) which comprises a nozzle (7) and is fixed in a weir pipe (2) submerged in the melted mass. The gas jet exits, enveloped by the liquid melted mass, into an underlying chamber (5), said chamber which is preferably embodied as a conversion furnace.

Description

 METHOD FOR PRODUCING COPPER BY SPRAYING A MELT CONTAINING COPPER RAW MATERIAL

The invention relates to a method for extracting copper from rich concentrate black copper or from copper stone or mat from copper and / or nickel smelting.

In the course of the extraction of copper, a number of processes have become known, in which mostly widespread copper ores, such as copper gravel or lime pyrite (CuFeS ₂ ) and copper luster (Cu ₂ S), are assumed. Such ores are mostly accompanied by other sulfidic ores and have adhesions, with sulfidic ores of iron, zinc, lead, antimony and arsenic as well as silver, gold and platinum metal-containing ores being known. The copper content of the ores in pure ore form is 2% by weight to 4% by weight and otherwise at most 0.5% by weight to 2% by weight. Such ores are therefore enriched before smelting, for which flotation processes are known, for example.

The raw copper extraction can in principle be carried out by pyrometallurgical or wet metallurgical methods. In which. The pyro-metallurgical process is melted by roasting according to various processes, such as floating roasting, copper stone or mat. The product is a melt mixture of the most varied copper-iron-sulfur compounds, which also carry a number of accompanying metals and are particularly rich in precious metals. In some cases, the bond contains selenium instead of sulfur. For the further processing of the stone or mat, a melt oxidation process is usually used and the material is blown in the converter, the converter copper being contaminated by Cu ₂ O. This converter copper is also called raw or black copper and is usually blistered and is therefore often referred to as blister copper.

In the past, the Peirce-S ith converter has established itself as the standard converter. This happens in more modern processes Melting to copper stone in a flash smelting process, which is followed by a flash converter. If such methods are operated with oxygen or with oxygen-enriched air, high concentrations of SO ₂ can be formed in the exhaust gas, which enable easier work-up and thus better exhaust gas purification.

In the more modern processes, which aim at a high S0 ₂ yield and good recovery, in particular in the form of sulfuric acid, the conversion of rich concentrates or copper or mat with oxidizing gases takes place in a flash converter, which is much higher Yields of S0 ₂ and in particular a higher concentration of S0 ₂ in the exhaust gas compared to conventional PS converters. In order to operate such a flash converter method, however, it is usually necessary to grind and crush the previously melted copper stone or mat or the previously formed rich concentrates in order to enable use in a flash converter. The corresponding grinding effort (60-100 Wh / t) is relatively high.

The invention now aims to provide a method of the type mentioned at the outset, with which an intermediate product for copper production, namely copper stone or mat powder, which is correspondingly finely comminuted and particularly favorable in granulation, is formed, which subsequently can be processed in a simple manner in a flash converter or to create a method with which a corresponding implementation or conversion can be carried out directly from rich concentrates or copper stone or mat without prior comminution.

To achieve this object, the method according to the invention essentially consists in that a rich concentrate, black copper and / or copper stone melt with an inert gas or oxidizing gases as the jacket of a gas jet is ejected and atomized. The fact that a melt is sprayed or atomized, then by cooling the atomized droplets, a correspondingly fine-grained granulate can be formed, which overall can be comminuted much more cost-effectively than would be the case in a complex grinding process. This applies all the more as copper stone or mat is usually present as a melt before it solidifies and is broken or ground. As a result of the fact that the melt is immediately processed further, the time-consuming comminution and grinding process can be eliminated, whereby this process control also offers the possibility in this stage of the comminution, if desired, a conversion with simultaneous conversion of sulfur to sulfur oxide and slagging of the copper accompanying elements, such as for example of iron. A comminution to particularly small particles and a particularly intensive implementation is achieved according to the invention in that the melt is expelled as a jacket of the gases. Due to their rapid expansion, the gases expelled inside the tubular melt jacket cause an explosive disintegration of the melt jet into the finest droplets. The fineness of the droplets also increases their total surface area, thus intensifying the reaction with the gas. If such a conversion is to be carried out in a flash converter, the solidified material can subsequently be further processed, for which purpose it is preferably carried out that solidified fine particles are fed to a burner, sulfides converted to SO _x and Fe to Fe _x O _y and are slagged with slag formers and Cu as blister copper or copper melt is removed or tapped separately from the slag. According to a particularly advantageous procedure, however, a reaction can be carried out directly in the molten droplets, for which the method is carried out in such a way that the copper concentrate or copper stone melt is ejected and atomized into a reactor with oxidizing gases such as air, oxygen and / or steam is reacted, preferably with the oxidizing gases, slag formers, and with the atomized copper concentrate melt droplets in the reactor become. In particular in this preferred method, in which mandatory oxidizing gases such as air, oxygen and / or steam are used for atomization and conversion, it should be noted that steam also prevails here under the prevailing temperatures and conditions, despite the simultaneous formation of hydrogen has an oxidizing effect, the process being able to be controlled or regulated in a particularly simple manner, in particular when using steam. The conversion of FeO with CaO to CaFe0 ₂ and the conversion of FeO with Si0 ₂ to FeSi0 ₃ , in other words the slagging, as well as the oxidation, are carried out as an exothermic process, with temperature control being achieved by injecting water vapor. For post-combustion, H ₂ formed can in turn be burned to form steam and the heat of combustion can be used to generate steam. The use of steam has the advantage that the S0 ₂ partial pressure formed by oxidation can be further increased after steam condensation in the exhaust gas, ^'' so that a particularly high S0 ₂ yield and thus particularly favorable conditions for an S0 ₂ or H ₂ S0 ₄ production are created. The oxidation and the slagging can be carried out very close to the stoichiometric conditions and the use of oxidizing agents leads to the conversion of CuFeS to Cu + FeO + S0 in the case of the reaction with mat, H _{2 being} additionally formed when steam is used becomes. The slagging leads to calcium ferrite if CaO is added and to Si0 ₂ if SiO is added

Fayalite, with a total of the rich concentrate or copper stone, blister copper or raw copper with a copper content of>

92% formed and the exhaust gas temperature in the order of

300 ° C to 400 ° C can be set, whereby an S0 ₂ or H ₂ S0 ₄ recovery is possible in a simple manner after the water vapor condensation. Overall, in this process the Peirce-Smith converter can turn the disadvantages of a high refractory wear, high maintenance costs, low oxidation efficiency and very dilute S0 ₂ in _A bgas, or a separate flash converter process are saved, which granulation and grinding and would require reheating the copper stone. The method according to the invention is carried out in a particularly simple manner in such a way that the oxidizing gases are injected via a lance and that slag formers such as CaO and / or SiO _{2 are} blown or sucked into a space surrounding the lance and delimited by a weir immersed in the melt. wherein the melt as - the oxidizing gases and the sucked-in slag formers, coaxial jacket surrounding ejected into the reactor, whereby subsequently the atomized and reacted with the slag formers melt is brought into a stove and the slag and the melt separately tapped or discharged become. The method according to the invention can thus be carried out with particularly simple devices, as have already been proposed for the atomization of oxidic slags, it being possible for the corresponding chemical reactions to be carried out at the same time.

In a particularly advantageous manner, the quality of the raw copper or blister copper obtained can be increased further by adding oxidizing agents to the melt collected in the hearth or pan via floor nozzles for refinement. An improvement in the energy balance can be achieved by using exhaust gases extracted from the stove to generate steam.

The invention is explained in more detail below on the basis of exemplary embodiments schematically shown in the drawing of a device suitable for carrying out the method according to the invention. The drawing shows a schematic representation of a device for the comminution and granulation of melt, with which a chemical reaction can optionally also be carried out and a melt bath can be obtained again.

In the drawing, 1 shows a tundish in which molten concentrate, black copper or a Copper stone or matt melt is introduced. A weir pipe 2 dips into the weld pool, which defines a corresponding annular gap between the lower edge of the weir pipe 2 and the bottom of the tundish 1. A corresponding outlet opening 4 is provided in the bottom 3 of the tundish, through which the melt flows out into a cooling or reaction chamber 5 located underneath. Appropriate inert gases or oxidizing gases are now optionally introduced via a lance 6 with a nozzle 7, steam also being able to be injected through this nozzle. The gas jet emerges coated from the liquid melt into the chamber below, the chamber. 5 if it is only intended to comminute the sprayed droplets of the melt, it can have corresponding cooling devices, in particular radiation coolers, on its walls. If a chemical conversion of copper stone or mat is to be prevented, the use of inert gases and steam is recommended. If steam is used, the thermal decomposition of steam and the oxidation that can be observed due to the formation of oxygen at least partially already result Conversion of sulfur to sulfur dioxide takes place. However, since in these cases the sulfur dioxide formed in the exhaust gases can be appropriately enriched by simply condensing steam, the comparatively small amounts of sulfur dioxide can also be effectively eliminated here. In order to improve the efficiency and, in particular, the atomization effect, an annular nozzle 20 can be arranged in a ring surrounding the escaping melt jet, which can be supplied via line 21 with steam, which is expelled against the melt jet.

If the starting material, namely rich concentrate or copper stone or mat is to be converted immediately and sulfur is to be converted into sulfur dioxide in large quantities, the molten material discharged as a jacket of the gases can be oxidized accordingly with oxygen-containing gases and in particular with oxygen-enriched air. The oxidation processes are exothermic, so that additional amounts of steam for controlling the temperatures can be injected via the lance 6. Via the annular space 8 surrounding the lance 6, slag formers can now be introduced directly from a metering device 9 or sucked in via the line 10. These slag formers primarily serve to convert the iron content in the copper stone or the molten mat to fayalite or ferritic melts, which float as slags on the correspondingly formed copper bath and in particular a blister copper bath. The blister copper bath is indicated schematically in the reactor 5 by 11, whereas the floating liquid slag is designated by 12. The exhaust gases formed can be used to generate steam, water being passed via the pump 13 and lines 14 via the cooling coils 15, which can be drawn off as steam via line 16. S0 ₂ can be withdrawn in high concentration from the chimney 17 and recovered.

Oxidizing agents can be injected via bottom nozzles 18 for refinement. If appropriate amounts of steam have been injected, H ₂ formed can be post-burned _to steam via lance 6. Additional oxygen is introduced via line 19, so that the heat of combustion can be used to generate steam. Overall, this schematically illustrated device either allows only a correspondingly comminuted material for the subsequent conversion, that is to say combustion of the sulfur content and slagging of the metals other than copper, or else the necessary conversion under oxidation directly from the melt of the as yet unconverted material des. Sulfur content to make. Instead of a stove, a pan can naturally also be used. Although this leads to a discontinuous process, however, only very small investments are made when converting existing facilities.

Claims

Claims: 1 . Process for the extraction of copper from rich concentrate black copper or from copper stone or mat from copper and / or nickel smelting, characterized in that a rich concentrate, black copper and / or copper stone melt with an inert gas or oxidizing gases is expelled as a jacket of a gas jet and is atomized. 2nd A method according to claim 1, characterized in that solidified fine particles are fed to a burner, sulfides converted to SO _x and Fe to Fe _x Oγ and slagged with slag formers and Cu as blister copper or copper melt is removed or tapped separately from the slag. 3. The method according to claim 1 or 2, characterized in that the copper concentrate or copper stone melt is ejected and atomized in a reactor with oxidizing gases such as air, oxygen and / or steam. 4. The method according to claim 3, characterized in that slag formers are sucked in with the oxidizing gases and reacted with the atomized copper concentrate drops of melt in the reactor. 5. The method according to any one of claims 1 to 4, characterized in that the oxidizing gases are injected via a lance and that in a space surrounding the lance, delimited by a weir immersed in the melt, slag formers such as CaO and / or Si0 ₂ or are sucked in, the melt being expelled into the reactor as the coaxial jacket surrounding the oxidizing gases and the sucked-in slag formers. 6. The method according to any one of claims 1 to 5, characterized in that the atomized and reacted with the slag formers melt is placed in a stove or a pan and that the slag and the melt are tapped or discharged separately. 7. The method according to any one of claims 1 to 6, characterized in that the melt collected in the stove or the pan is mixed with oxidizing agents for refining via floor nozzles. 8. The method according to any one of claims 1 to 7, characterized in that exhaust gases drawn off from the stove or the pan are used to generate steam.