JP2007515549A - Copper production method by dry smelting in converter - Google Patents

Abstract

The invention relates to a method for the pyrometallurgical production of copper in a converter is provided. According to said method, gas is introduced into the respective molten charge during all steps thereof (charging the converter with cupriferous crude melt, treating the molten charge to obtain Cu 2 S and slag, removing the slag, converting Cu 2 S into Cu, emptying the converter).

Description

  The present invention relates to a method for producing copper by pyrometallurgical in a converter.

  In so-called dry smelting of crude copper, for example, copper matte and / or secondary raw materials are used as raw materials. The object is to produce so-called crude copper having a purity of at least 96% by weight, preferably 99% by weight. Of course, attempts have been made to bring the purity as close as possible to 100% by weight.

  An essential part of such copper production lies in the so-called “conversion” in the converter. Such a transformation is known by the name of Pierce Smith and Hoboken.

  For such converter processing, first, a melt containing copper is filled into the converter (supplied into the converter).

In the next processing step, foreign components, in particular iron sulfide, are removed as much as possible, or more precisely converted to slag. This process, also called “slagging”, refines the copper melt so that it is mostly made up of only Cu ₂ S (also called “white metal”). The purpose is to do.

  Slugging includes the subsequent removal of slag from the converter.

In order to produce crude copper from Cu ₂ S, a secondary metallurgical method is known. In this method, a gas (particularly oxygen) is sprayed on the melt (see Patent Document 1). Thereby, sulfur and other impurities (for example, nickel) are removed as much as possible. From the description in Patent Document 1, it can be deduced that the nickel content exceeds 1.0% by weight.

  Finally, the crude copper so formed is removed from the converter.

  Although this method is widely used, it has several drawbacks. For example, slag typically must be removed through the furnace feed opening during "slagging". This increases the risk of losing valuable copper melt. Further, in this conventional method, it takes a considerable time to obtain the above-described high purity.

Patent Document 2 discloses a process for removing sulfur from molten copper. Thereby, the melt is treated with a gas containing oxygen in a region exceeding half the depth of the metal bath. At the same time, the circulating gas is introduced to a considerable distance below half the depth of the metal bath, and the introduction of the circulating gas is continued even after the supply of oxygen is completed.

In order to reduce the scattering that leads to increased wear and adhesion, US Pat. It is agitated by spraying in a gas below the bath surface.

Patent document 3 relates to a process for converting an iron mat, in which the melt itself is agitated by an inert gas while oxygen is sprayed onto the melt surface. .
U.S. Pat. No. 4,830,667 German Patent Application Publication No. 3809477 US Pat. No. 5,215,571

  The object of the present invention is to optimize known methods. Copper production must be done in a shorter time and / or with higher purity.

  The present invention has been made from the following considerations: No metallurgical work is performed in the reactor when filling (feeding) the converter. The furnace simply acts as a “buffer” or “holding unit”. This also applies to the final process step where all the melt is removed from the converter.

  According to the invention, these process steps are also used for secondary metallurgical processing of the melt. In other words, the processing gas has already been introduced into the molten metal (molten copper) when filling the converter. This has the advantage that the so-called “slugging” step is started almost simultaneously with filling and without a time delay. The converter is enabled at the first moment in the melt processing interval.

  This applies until the melt is removed from the converter.

  The cleaning process during "deslagging" has the advantage of removing impurities and promoting slag formation.

  In this process step, a gas purification / washing process can be used to achieve another effect. By selective operation of the metal bath, the slag can be selectively guided in the direction of the converter opening, and the slag is removed from the opening. In this way, a more precise segregation between the slag on one side and the melt on the other side is achieved and the melt loss observed in the prior art can be avoided.

Thus, in the most general embodiment, the present invention relates to a method for producing copper by dry smelting in a converter with the following characteristics:
a) filling the converter with a melt containing copper;
b) treating the melt to convert impurities to slag until the majority of the melt is occupied solely by Cu ₂ S;
c) removing slag from the converter;
d) blowing a gas over the melt containing Cu ₂ S to purify very pure copper by removing sulfur;
e) removing all melt from the converter and sending it to the downstream unit;
With this,
f) introducing a gas into each melt during the process steps a), b), c) and e);
It is characterized by having.

  The gas used in the process steps a), b), c) and e) is mostly or entirely occupied by oxygen, as is the gas used in the process step d). It is also possible to use other gases including inert gases.

  At the end of process step d), a fraction of oxygen is reduced in a selective manner and replaced by some inert gas. Towards the end of this process step, the portion of the inert gas may be in an amount greater than 50% and the portion of oxygen may initially be an amount well above 50%. In this way, generation of monovalent copper oxide (copper (I) oxide) can be minimized. The treatment with inert gas can be continued also in process step e).

  The actual conversion process in process step d) can be expressed chemically as follows:

  It takes about 1 hour to remove 300 tons of crude copper from the converter. According to the invention, the metal melt also undergoes a reaction (treated) during this removal stage. Accordingly, secondary metallurgical methods of molten copper are performed throughout the entire conversion process.

  The gas supply (s) is performed via a plurality of gas purification / cleaning devices. Such gas purifiers (gas cleaning bricks) have been known for decades, especially in the field of steel melt processing. According to the present invention, such a gas purifier can be easily introduced. As the gas cleaning device, either a directional porous device (directed porosity) or a non-directed porous device (non-directed porosity) can be used. Some groups of porous devices with directionality are provided with generally straight slits or passages through which the gas formed in the gas scrubber is transported. Non-directional porous devices are designed in a “sponge” shape. The gas must move through the body from space to space.

  Such gas purifiers (or nozzle type cleaning devices) may be used individually or in groups at the bottom and / or wall of the converter. According to the present invention, the gas purifiers are prepared to be operated individually, in pre-selectable groups, or all simultaneously. Again, different gases or different gas pressures can be supplied to individual gas purification devices or groups of gas purification devices.

  It is preferable to provide an appropriate gas regulator for this purpose. In the latter case, the operation of the metal melt can be adjusted so that the slag floating on the metal melt flows in a specific flow direction, for example in the direction of the tapping opening. .

  This method can be carried out such that the gas (s) is introduced into the melt (by spraying, jetting) without interruption during all processing steps.

  The gas and gas volume and / or gas pressure can be changed during the individual processing steps.

  For example, in a converter capable of accommodating 300 tons of crude copper, for example, 10 gas cleaning apparatuses are provided, and each cleaning rate can be 200 liters per minute.

  According to this method, at least the purity of the prior art level can be accommodated, and copper can be produced by dry smelting at a very high speed with a purity well exceeding 99.5% by weight.

Claims (10)

A method for producing copper by dry smelting,
a) filling the converter with a melt containing copper;
b) treating the melt to convert impurities to slag until a majority of the melt is occupied solely by Cu ₂ S;
c) removing the slag from the converter;
d) blowing a gas to the melt containing Cu ₂ S to purify very pure copper by removing sulfur content;
e) removing all of the melt from the converter and sending it to a downstream unit;
With this,
f) introducing a gas into each of the melts during the process steps a), b), c) and e);
A method characterized by comprising:   2. The method according to claim 1, further comprising the step of introducing a gas consisting essentially of oxygen into the melt during the process step a).   2. The method according to claim 1, further comprising the step of introducing a gas consisting essentially of oxygen into the melt during the process step b).   2. A method according to claim 1, characterized in that it comprises the step of introducing a gas consisting essentially of oxygen into the melt during the process step d).   2. The method according to claim 1, further comprising the step of introducing a gas consisting essentially of oxygen into the melt during the process step e).   2. The method according to claim 1, comprising the step of making the gas supplied at least partly an inert gas at least in the second half of the process step e).   Introducing the gas through a plurality of gas scrubbers and supplying the gas scrubbers with the same or different gases in a preselectable combination and / or with a preselectable pressure. The method according to claim 1, comprising:   8. The method according to claim 7, further comprising the step of introducing the gas so that the slag is selectively conveyed in the direction of the opening of the extraction port in the process step c). Method.   The method according to claim 1, further comprising the step of introducing gas into the melt without interruption during all the process steps.   The method according to claim 9, comprising introducing the gas at different compositions, amounts and / or different gas pressures during each of the process steps.