AUSTRALIA FB RICE & CO Patent and Trade Mark Attorneys Patents Act 1990 XIANGGUANG COPPER CO., LTD COMPLETE SPECIFICATION STANDARD PATENT Invention Title: An anode refinement method for high-sulfur content coarse copper The following statement is a full description of this invention including the best method of performing it known to us:- 2 An anode refinement method for high-sulfur content coarse copper Technical field The invention relates to copper metallurgy, and more specifically to a 5 refinement technique for high-sulfur content coarse copper. Background technology The "Double-flash" copper-refining technique is: copper concentrate -flash melting -> matte -flash converting - coarse copper ->positive-pole refinement 10 -+anode copper ->electrolysis -+ high-purity cathode copper. As the most advanced technique in copper refinement at present, it represents the development direction in the future, but sulfur content in the coarse copper produced in flash converting process is higher than that in traditional PS furnace converting. Sulfur content in flash converting is 0.1-5%, while that in PS furnace converting is 0.03-0.08%. Now, the traditional 15 method of deep oxidization and reduction is still adopted for the fire-refining of these high-sulfur content coarse copper, i.e. air or oxygen is first led in to carry out deep oxidization to reduce the sulfur content in copper liquid to less than 0.003%, then reducers are used, such as natural gas, liquefied petroleum, heavy oil, diesel oil or pulverized coal to conduct deep reduction to eliminate surplus oxygen. This method, 20 featured with first deep oxidization and then deep reduction, will not only consume large amounts of natural gas and other nonrenewable resources, wasting energy sources, but also prolong refining time, reduce refining efficiency, and the working condition is bad, environment pollution severe. Any discussion of documents, acts, materials, devices, articles or the like which 25 has been included in the present specification is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present disclosure as it existed before the priority date of each claim of this application. 30 Summary of the Invention The present invention provides an anode refinement method for high-sulfur content coarse copper, which in at least a preferred embodiment, effectively saves working time, improves production efficiency and capacity, conserves energy, and eliminates air pollution of black smoke into the atmospheric environment. 35 The invention is realized by the following technical scheme: while high-sulfur coarse copper liquid from flash converting furnace flows to the anode furnace through a 3 chute, inert gas is continuously added, to make the copper liquid boiling, and improve discharging of the SO 2 produced from reaction of the sulfur with oxygen in the liquid and the oxygen absorbed from atmosphere, so as to remove more than about 90% sulfur in the coarse copper liquid. After the coarse copper liquid is fully led to the anode 5 furnace, operations of low-oxidization and low-reduction, non-oxidization and low reduction or cancel of reduction-oxidization is conducted according to sulfur content in the copper liquid. Accordingly, in one aspect the invention provides a method for refining high sulfur content coarse copper, comprising: 10 continuously adding an inert gas to a high-sulfur coarse copper liquid, as it flows from a flash converting furnace to an anode furnace, to stir the copper liquid and remove more than about 90% sulfur from the coarse copper liquid by discharge of SO 2 produced from reaction of sulfur with oxygen in the liquid and the atmosphere; after the coarse copper liquid has been fully led to the anode furnace, conducting 15 an operation of i) low-oxidization and low-reduction or ii) non-oxidization and low reduction or iii) cancelling the operation of i) or ii), according to the sulfur content of the copper liquid. In one embodiment low-oxidization and low-reduction operation is adopted if the sulfur content of the copper liquid is more than about 0.05%, that is to say, to 20 conduct low-reduction while the sulfur is reduced to about 0.05% through low oxidization. In another embodiment, if the sulfur content is less than about 0.05%, non-oxidization and low-reduction is adopted. In another embodiment, if the sulfur content is less than 0.003% and oxygen content less than about 0.2%, reduction oxidization operation (i.e. low-oxidization and low-reduction or non-oxidization) is 25 cancelled. In other embodiments, the value of sulfur content to determine choice of operation can also be about 0.07%, about 0.08% or about 0.1%, but the working time will be the shortest and efficiency highest only when it is about 0.05%. In other specific embodiments, the coarse copper liquid flows to the anode furnace with flow rate of about 50-100 tons per hour; the flow rate of inert gas is about 30 50~2000Nm 3 /h, pressure about 0.4-0.8MPa, temperature about 25-300"C; the air flow rate for low-oxidization about 100-l00ONm 3 /h, pressure about 0.3-0.8MPa; the gas flow rate for low-reduction about 100-100ONm 3 /h, pressure about 0.3-0.8MPa, pressure in furnace ±200Pa. In another embodiment, the inert gas is argon or nitrogen; the reduction gases 35 may be natural gas, liquefied petroleum gas or city gas, etc. In yet another embodiment, the inert gas is blown to the anode furnace through ventilation installation 4 at the bottom of the furnace, and preferably, the ventilation installation are the ventilation bricks at the bottom of the furnace. The method of the invention is applicable for refinement of high-sulfur content coarse copper, preferably with sulfur content in coarse copper of about 0.1%-5%, from all kinds of metallurgic furnaces. 5 The principles of the invention in at least a preferred embodiment include: in traditional anode refinement process for high-sulfur content coarse copper, deep oxidization and reduction is adopted, i.e. after the high-sulfur content coarse copper produced in flash converting is led to anode furnace, blow air or oxygen from air-inlet of anode furnace to conduct deep oxidization and reduce sulfur content of the copper 10 liquid to less than about 0.003%, then carry out deep reduction with reduction gas (if natural gas, the flow rate about 3500Nm 3 /h). Industrial practice indicates that, because Cu is much more than S in coarse copper liquid, the efficiency of deep oxidization is not high, especially for the process of reducing sulfur from about 0.05% to 0.003%, the oxidization efficiency is very low and oxidization time extremely long. For an anode 15 furnace with capacity of about 500 tons, oxidization time of every furnace of copper will be as long as about 10 hours, and while sulfur content is reduced to less than about 0.003% in deep oxidization, oxygen in the copper liquid will reach about 0.8-1.5%, which demands large amounts of reduction gas to carry out deep reduction and reduce oxygen to less than about 0.2%. 20 The core content of the invention in at least a preferred embodiment include: first, inert gas is continuously put in during the whole anode feeding course, to make sulfur in the coarse copper liquid react in priority with oxygen in the liquid or with that absorbed from atmosphere: Cu 2 S+2Cu 2 O=6Cu+SO2 25 Cu 2 S+0 2 =2Cu+SO 2 , so as to eliminate sulfur; Second, conduct low-oxidization and low-reduction operation, i.e. to carry out reduction while the sulfur is reduced to about 0.05% through low oxidization, but not to start deep reduction till the sulfur is reduced to less than about 0.003% through deep-oxidization in traditional technique. The process of inletting inert 30 gas during the course of anode furnace feeding, which can make the sulfur in coarse copper liquid react fully with oxygen in the liquid or oxygen absorbed from atmosphere, is the key to reduce refining time drastically. Coarse copper liquid produced from flash converting is led to the anode furnace in a rate of about 50-100 tons per hour. To an anode furnace with capacity of about 500 35 tones, the course will last for five to ten hours, and during which, sulfur can be eliminated in the form of SO 2 through reaction between the sulfur and oxygen in the 5 liquid and that absorbed from atmosphere as long as inert gas is continuously inlet through ventilation installation at the bottom of the anode furnace and make coarse copper liquid stirring and boiling. After anode furnace feeding, carry out low (no) oxidization and low (no) 5 reduction according to the sulfur content in the anode furnace. While sulfur content of the copper liquid is more than about 0.05%, low oxidization and low reduction is adopted, i.e. blow air through air-inlet of the anode furnace to carry out low oxidization till the sulfur content is reduced to about 0.05%, and then let in reduction gas through air-inlet of the anode furnace to carry out low 10 reduction. While sulfur content of the copper liquid is less than or equal to about 0.05%, non-oxidization and low-reduction is adopted, i.e. let in natural gas or other reduction gas directly from air-inlet of the anode furnace to carry out low-reduction on the liquid, with major reactions as follows: 15 4Cu 2 0+CH 4 =8Cu+CO 2 +2H 2 0 Cu 2 S+2Cu 2 O=6Cu+SO 2 , till final sulfur content < about 0.003%, and oxygen content<0.2%. While sulfur content of the copper liquid : about 0.003% and oxygen content < about 0.2%, oxidization and reduction process can be cancelled, with anode plate 20 casting directly performed. The inert gases are argon, nitrogen and other gases that will not participate in the process chemical reaction. The reduction gases may be natural gas, liquefied petroleum, city gas, and so on. The invention is applicable to the refinement of high-sulfur content coarse 25 copper, with sulfur content about 0.1%-5%, produced from all kinds metallurgic furnace. The technological parameters of at least a preferred embodiment include: high sulfur coarse copper liquid flows to the anode furnace in a rate of about 50-100 tons per hour; inert gas flow rate about 50-2000Nm 3 /h (determined by the capacity of the 30 furnace), pressure about 0.4-0.8MPa, temperature about 25C -300'C; reduction gas flow rate 100-1 OOONm 3 /h (determined by the capacity of the furnace), pressure about 0.3-0.8MPa, inside-furnace pressure about 200Pa; low oxidization air flow rate about 100-100ONm 3 /h (determined by the capacity of the furnace), pressure about 0.3-0.8MPa; ventilation facilities about 1~10 units (determined by the capacity of 35 the furnace), refining time about 2 hours.
6 As mentioned above, the advantages of the invention are that it can cancel deep oxidization and deep-reduction process in the anode furnace, reduce working time from about 10 hours to less than about 2 hours, notably improve production efficiency and capacity of the anode furnace, save energy, reduce consumption of natural gas and 5 other reducers by more than about 70%, and resolve the pollution problem of black smoke. Moreover, the anode plates produced in the method above will meet requirements for electrolysis, i.e. the content of Cu> 99.3%, S <0.003% and 0 <0.2%. Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated 10 element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps. Figures attachment Fig. I is the structural diagram of anode furnace in the invention, in which the 15 anode furnace is connected with chute and air pipes. Tabs in the figure: 1 chute, 2 anode furnace, 3 ventilation installation, 4 air inlet, 5 air pipes. Specific performance 20 Reference figure 1 specifically indicates the technological process: pour coarse copper produced in flash converting furnace to anode furnace 2 through the chute I in a rate of 50- 100 tons per hour, and during the course, continuously blow inert gas into the furnace through the ventilation facilities 3 at the bottom of the anode furnace 2 in a rate of 50-2000Nm 3 /h (determined by the capacity of the furnace), pressure 25 0.4-0.8MPa and temperature 25"C-300"C. Inert gas keeps the coarse copper liquid boiling and improves reaction between the sulfur and oxygen in the liquid and that absorbed through liquid surface; produced SO 2 is discharged from the liquid to reach the goal of sulfur elimination. After the feeding course, low (no) oxidization and low (no) reduction is adopted according to the sulfur content of copper liquid in anode 30 furnace 2. While the sulfur content of copper liquid >0.05%, low oxidization and low reduction is conducted, i.e. air is led in through air inlet 4 on the lateral wall of anode furnace 2 to perform low-oxidization, with air flow rate 100- I 00ONm 3 /h (determined by the capacity of the anode furnace), pressure 0.3-0.8MPa, till the sulfur content in 35 the liquid is less than 0.05%. Then, low-reduction is conducted by the inlet of natural gas to anode furnace 2 through air inlet 4, with flow rate of natural gas 7 100-1000Nm 3 /h, pressure 0.3-0.8MPa, until the sulfur content of the copper liquid 50.003% and oxygen content <0.2%. While the sulfur content of copper liquid <0.05%, non-oxidization and low reduction is conducted, i.e. natural gas is directly led in through air inlet 4 on the lateral 5 wall of anode furnace 2 to perform low-reduction, with the flow rate of natural gas 100-100ONm 3 /h, pressure 0.3-0.8MPa, until the sulfur content of the copper liquid <0.003% and oxygen content <0.2%. While the sulfur content of copper liquid 50.003% and oxygen content <0.2%, the oxidization and reduction process can be cancelled, with anode plate casting 10 directly conducted. To further improve the stirring effect of inert gas on copper liquid and raise production efficiency, inert gas can be led into anode furnace 2 through ventilation installation 3 and air inlet 4 jointly in practice. The technological scheme of the invention is not limited to the scope of the 15 practical examples stated. All the technical content that not described here for detail is public-known.