JPS60500453A - Method for adding thioureas to electrolytic solutions useful for copper smelting - Google Patents

Abstract

Method for electrolytically refining copper involving precise control of the thiourea concentrations in the copper sulfate, sulfuric acid solution used in the refining whereby improvements are obtained in tankhouse current efficiencies and the quality of the refined copper deposited on the cathodes. Sufficient thiourea is added to the electrolyte feed so that at least above trace quantities are measured in the electrolyte outflow.

Description

[Detailed description of the invention] Background technology for adding thioureas to electrolytic solutions useful for copper refining The present invention relates to the electrolytic refining of copper, and more specifically, to the electrolytic refining of copper. The present invention relates to a method for constantly maintaining the concentration of substances.

Traditionally copper is a substantially pure copper deposit plated with an impure copper cast anode. between the cathode (both anode and cathode are immersed in a suitable electrolyte) with It has been purified in a manner that conveys it. Generally accepted in the art The solution is an aqueous solution of copper sulfate and sulfuric acid. In this refining method, impure anodic mud is first into the electrolyte and then transfer the steel ions (Cu　'') to the nearby cathode, where they are Copper is deposited as almost pure metal Cu''. After a certain period of time, the desired thickness is deposited. Copper deposits on the cathode, where they are extracted and later used in several commonly used products. 6 melted to cast into shape.

Several problems arise in this operation, which have resulted in the subject of extensive research. It was. As energy costs continue to rise, increasing current efficiency in electrolytic refining is essential. The importance of ensuring safety became a key requirement. In a large modern copper and metal smelter If the current efficiency changes by 1 inch, the copper capacity increases substantially, or per unit of production. The amount of electricity can be reduced. In addition, the current efficiency can be improved without sacrificing current efficiency. It is desirable to operate at a higher tankhouse current density. Such improvements the copper and some desirable by-products, such as silver, in larger quantities and more rapidly. 2 Labor costs will be lower because of increased recovery and less need for shift work.

Various additives, such as U.S. Patent Nos. 2,660,555 and 3.389.0. No. 64 was used to improve the quality of the copper deposited on the cathode.

In particular, the combination of glue Avitone and thiourea (hereinafter referred to as 1 thiourea) Ureas 1 are pure or commercial thioureas, as well as most thioureas, including thiourea foundations. organic compounds such as those described in U.S. Pat. No. 3,389.064. (understood as representing the It was observed that the formation of precipitates was promoted. If you do not use any of these additives , the copper deposited on the cathode tends to form a single adule. It grows in a regular dendritic pattern and often causes harmful short circuits during operation. Also at the cathode Large “vertical wrinkles” (5triations), which are groove-like growths, exist in the electrolyte. There is a possibility of trapping existing impurities, especially at impurity concentrations (particularly thiourea concentrations). dangerous if the electrolyte (considered to be Ru.

The problems caused by the use of additives are the optimum operating concentration in the smelting tank house and the It must be determined precisely and accurately, and how the current The idea was to increase efficiency. In U.S. Patent No. 3,389.064 does not clarify the chemistry of the listed additives in the electrolyte, but rather It is estimated that the additive will be used up during the electrolytic refining operation. but In any large-scale commercial operation, including tankhouse refining, effective operation is essential. The production will depend on the number of variables. Therefore, the system operates under constant conditions under the overall maximum operating conditions. To keep the system running, critical parameters within the system must be measured quickly and accurately. (without resorting to old-fashioned trial-and-error readjustments) It is desirable to find a method for determining the entire additive concentration range.

Purpose of invention Therefore, an advantage of the present invention is that it provides an improved method for use in the electrolytic refining of copper. Ru.

Another advantage of the invention is that it increases current efficiency and thus reduces cane handling costs and labor intensity. An improved copper electrolytic refining method is provided.

Another advantage of the present invention is that thioureas at a concentration similar to that of the cathodically deposited copper during the electrolytic process are It is to be determined what effect the total thickness will have on the quality.

Summary of the invention These and other advantages of Honka Dan are made from sulfuric acid and sulfuric acid steel, as well as low weight additives. (one of which is thioureas) was prepared completely, and the electrolyte solution for copper refining containing When the electrolyte is plated, the electrolyte passes through all the inflow and outflow conduction means. in suitable container means with both an inlet stream and an effluent stream; thioureas; The concentration in the effluent stream should be at least as high as the trace concentration, i.e. at least measurable. Sufficient thiourea is added to the influent stream to maintain a The maximum permissible concentration of Above this point, impurities present in the electrolyte will have a physical effect on the quality of the deposited copper. and during electrolytic refining in a copper vessel means at least a period of Achieved by an improved method of electrolytic refining of copper, consisting of repeated be done.

Brief description of the drawing M1 diagrams A and B show the outline of an alternative method in which the anode and cathode are placed alternately in an electrolytic cell. Full view.

Figure 2 shows a copper electrolyte circulation cycle in which the tank house consists of a single section.

detailed description of the invention Approximately 95% of all copper produced today goes from mined ore to the final product. It is estimated that it is purified by electrolysis during processing. Electrolytic refining first removes impurities from the anode. The copper is chemically eluted and then the eluted copper is selectively deposited in its qualitatively pure form onto the cathode. This is a way of looking at it. This method of building therefore serves two purposes.

i.e. it virtually eliminates all impurities that are detrimental to the electrical and mechanical properties of copper. and separated from valuable impurities11, if this is economically practical. can be recovered as a by-product or otherwise disposed of.

The electrolytic refining that takes place today in industrial tankhouses is almost without exception In this case, the anode and cathode in each electrolytic cell are are inserted between them in an electrically parallel arrangement. Figures IA and IB show anode-cathode Two alternative methods of arranging the pole and cell connections are shown. In each embodiment, The anodes 2A, 2B in each bath are all activated at a potential, while all the cathodes 4 A and 4B are at a second potential lower than this. Each anode 2A, 2B placed between the two cathodes 4A, 4B such that the poles dissolve at a substantially uniform rate. It will be done.

Each species is electrically grafted in sequence to form a complete section, typically about 20 to 45 specimens. In each case, the power and ramifications are separated and distinct parts (modules) of the ruren tank house. ) This includes inserting and removing the electrode, and cleaning the remaining amount of anode from the bottom of the cypress. Which operation as well as maintenance! electrically and chemically separated from other sections for They may be separated.

Each type of adjacent tank is connected to its adjacent member in turn, and all cathodes in each tank are connected to each adjacent member. It is directly connected to the anode in the tank. That is, they are at the same potential.

Today's steel refining V (the electrolyte used is 40-50 g/e of steel and 175 ~225g/L and Shaojun's impurity (nickel, arsenic, iron and antimony).

A steam heater maintains the temperature at approximately 60 to 65 degrees Celsius at the entrance of the entire bathhouse refining tank. As the electrolyte circulates during copper processing, its temperature at the outlet ranges from about 55 to The temperature drops to 60°C. Depending on the flow rate or circulation of the electrolyte in and out of the cell A typical large industrial tank recirculates its electrolyte once every 5 to 6 hours. child Such a cycle is essential for several reasons. One of them is dissolved impurities outside the gold knob. transport to the surface of the electrode and ensure a uniform -fL steel ion density at the surface of the electrode. That is.

The electrolyte contains several additives that are added to it to improve its overall performance. child These additives are mixed into the electrolyte 7'1. ,t field 6 In this case, the final plated copper deposit will be soft or coarsely crystalline. It will be. Growth of copper “nodules” on the cathode (often when these touch the adjacent anode) grow to the touch, thus producing a short circuit sound), and in order to eliminate these It would require additional manpower and also reduce tank house current efficiency. now Common additives used at Nikkei Renjo include bone glue, casein melt, and sultinized Motobu fibers such as goulac, bindar ene) and lignon, and petroleum oil (petra) 7 abitoyA" . Additives of this type have been recognized as being of vital importance in optimizing the refining potential. One is to use controlled amounts of thiourea. Thio used here Ureas are all organic compounds containing the thiourea nucleus -rfL, especially those that are commercially pure. All means stylish or commercial thiourea.

However, due to the small amount of thiourea it contains (usually in the electrolyte) and especially in the electrolyte Because it is difficult to measure these concentrations in The behavior of urea is virtually unknown. In particular, thiourea is depleted during tankhouse operation. The rate at which thiourea is consumed, the effect that thiourea has on the deposited copper cathode at a concentration level of The effects of increasing the impurity concentration in the electrolyte and electrolyte are of great interest. industry Traditionally, if the method of controlling the growth of nodules and vertical stripes is to improve the % current efficiency, then The quality of the copper deposited on the cathode has been very unscientifically manipulated.

Therefore, it is important to understand these various phenomena better and devise ways to control them. This was the goal of industry.

This is how the left method was discovered. By looking at Figure 82, its widest embodiment is the most well understood. A schematic process diagram of tank house refining consisting of a single section. Dechiru. Mixer tank 2 serves as a source of thioureas for the refining process and also for other purposes. It is used as a source of additives and additive salts. Thioureas are Continuously or periodically depending on the type of system used can be added. The thioureas in tank 2 are passed through pipes or other suitable distribution means 4. It then passes through the flow regulator 6, where it joins the main circulation of the electrolyte in the tube 8. Like this The flow of thioureas in tube 8 can be adjusted by adjusting the amount of thioureas added with the formula Concentrations in the incoming stream generally range from about 8oo to 2500 ppb, most commonly from about 1500 to Maintained at 2000 ppb.

However, the concentration in the influent stream is the concentration of thioureas in the effluent stream from each tank house part. in at least a trace concentration, i.e. at least a measurable amount, preferably a small It should be in a range such that at least about 100 ppb is present. Surprisingly, suitable It is possible to use thioureas in the total influent stream at a higher water pressure than was thought to be necessary. It has been found that there are no harmful consequences. Especially about 5000 ppb of thioureas Satisfactory results were obtained using the entire influent stream. This was completely unexpected.

These high levels of thioureas (particularly due to the contamination of sulfur present in thioureas) This was because it was believed that this would damage the deposited copper cathode.

However, there are no economic or other benefits to be gained by operating at such alarming levels. Not possible.

Referring to FIG. I enter module 10. Each row has a complete construction in the manner shown in FIG. deer However, any suitable boat or tank house design may also be used in the method of the present invention. With this tankhouse design (ζ analysis) there is only a single section It is used for heating the temperature source Kj. The electrolyte is circulated in section 10r, and all impure anodes are After participating in the electrolytic phase conduction to the pure copper cathode, it is discharged through the discharge pipe 14. . The concentration of thioureas in the electrolyte in the effluent stream is determined by taking a sample at the orifice 16, Next, 5) Measurement is carried out by measuring the whole sample using the lever measuring means 18.

Concentrations in the effluent stream can be measured quickly and accurately, and changes in the system can be made quickly. As long as the position of the foot means is not important.

water difference pulse polarography (d, if, = rential pulsep Analyzing stains using an analytical technique known as olaography (DPP) It is preferable to measure the red color of thioureas in the fission (IL), Analyzer housings known as ・Research model≠384 (published by Princeton Applied Research) Princeton, Jersey)! 7 Currently commercially available, its operating method is described in publications. EG&G Princeton Applied Research Company Analytical Instruments Department (quoted for reference in the description) and by % also this equipment by the insertion of other reference electrodes i.e. there is recommended Ag-Ag (modified by using KNO3 reference electrode instead of J electrode) By changing the temperature, it is possible to record the entire concentration of thioureas of about 100 ppb. Wear. The electrolyte in the tank house is diluted to 1/1o concentration and analyzed. Fully dilute electrolyte Is the reason for the analysis interference due to other additives present, especially chlorine? This is to remove . To best display the polarograph reading, the polarograph should be approximately Set to a slow scan rate of 2-5 mV/s, and a pulse height of 25 mV. It is preferable. This method allows accurate concentrations down to approximately 100 J) pb. The reading is obtained. This means that although the manufacturer claims to the contrary, this machine cannot be achieved using the recommended method for operation. But a proper polarograph is Both can be immediately withdrawn for use in the method of the present invention, and Any other measurement method that can quickly and accurately determine the concentration of ureas is based on this invention. It is well suited for the light method. However, it is thought that it is not currently commercially available.

Surprisingly, the concentration of thioureas in the effluent increases/is important when optimizing the efficiency of thioureas. It was found that parameters. More specifically, at least trace concentration values i.e. in at least a measurable amount, preferably about 100 ppb or less. The concentration of the above thioureas in the effluent increases the current efficiency and makes it more uniform. The cathode is obtained, the short circuit between the anode and the cathode is reduced, and the impurity concentration in the cathode is more It gets lower.

The circulating electrolyte is passed through the tube 20 at 10 after the sample is taken at 16. and flows into tank 22. This is a fresh electrolyte, i.e. Cu5O4 and H Used as a source of 2SO4. When the fresh electrode i is completely discharged from the tank 22, the pipe 24 and passes through pumping means 26 into heat exchanger 30 and blue 28. this is The temperature of the electrolyte is increased to approximately 65°C, at which point the liquid is discharged through tube 32 and into the head. Enter Dotank 34 and leave now. The electrolyte is then added with thioureas and other additions. After replenishing the agent, section 10 is entered and the cycle continues indefinitely. this method Many other recirculation mechanisms and associated devices also fall within the scope of this invention. This should be fully emphasized. The total content of thioureas in the electrolyte stream was determined. Treatment of the electrolyte until it is subsequently replenished with the desired amount of thiourea in the influent stream. This is because the law does not constitute a decisive part of the method.

A preferred form of the invention is carried out in a tank house or other suitable container means; The improvement is that the concentration of thioureas in the electrolyte effluent stream can be determined by appropriate measuring means, p (preferably 1 or by differential pulse polarography) to determine the desired concentration in the effluent stream. By adding an amount of thiourea effective to keep the total influent flow within The concentration of thioureas is readjusted, and beyond that range impurities will appear in the copper cathode. at least a measurable fL below which nodule formation is promoted. amount, preferably with a minimum concentration that is about 100 ppb; repeatedly, so that f) the measured concentration of thioureas in the effluent stream exceeds these maximum and the minimum value, preferably about 100 to 2 per typical electrolytic phase line tackhouse 5001) From a new and improved copper electrolytic refining process consisting of pb. Become.

Although the inventors do not wish to be bound by theory, the points of the piers inside the tank house By using DPP to measure the concentration of thioureas in I think that how the element is consumed becomes 1 sword. Strict thioureas The optimum 6th degree varies from unit to unit and must be determined experimentally for each unit. do not have. Thioureas decrease over time even in a non-electrolyzed state. Tashino erasure It seems that the cost speed (iN) is proportional to the current density.

The most surprising thing about Akemi is that he is monitoring the concentration of thioureas using an uninvented method. The result is a 3-6% improvement in current density and up to 80% reduction in short circuits. Ru. Table 1 shows the current efficiency (C0E-) and the total number of short circuits in the factory. It was compiled over a period of four months. Thiourea, Glue and Avit for the first month general procedures, including adding chlorine to the electrolyte according to generally accepted practice. What refining technology? during the last 3 months using the original method of the present invention. the first Although measurements showed the absence of thiourea in the effluent, according to the technique of the present invention, Therefore, it is possible to detect a measurable amount of thiourea in the effluent. Adding a radiator IC to the tank house module reduces the number of short circuits. It was observed that the average flow efficiency increased. Table 2 shows two tank tanks. for 9 days in a mouse module, both before and after employing the entire method of the invention. The number of short circuits that occurred after adopting this method is shown.

A dramatic increase in N-line current efficiency and short circuits occurred as shown in Tables 1 and 2. The decrease in frequency was a totally unexpected development.2 It is. In contrast, the normal Efan is A/ft2 (183 An is A/m2) High current efficiency of 23 amps/ft2 (2487 amps/ft2) reduces current density. This was achieved without sacrificing anything. The results depend on the characteristics of each tank house used. The method that has been operating in its current state for decades (substantially It is a very surprising and unexpected result that substantial economic savings have been made in It is clear that this is the result.

Obviously, taking into account the above techniques, a large number of modifications and changes have been made to the method of the present invention. It can be done. Therefore, within the scope of the claims, non-inventions do not include forms other than those detailed above. It should be understood that it is possible to give alms.

Table 1 Month module number of short circuits leaked 1 color of urine g"c, E, %1 or doorstop person 67g 93.18 B 749 92.43 0 759 - 90.15 2 months A 336 + 96.32B 382 labor 9611 ※※ C381+/-94,79 D 330 94.38 E 322 4-94.58 3 months A 327 + 96.54 B 371 + 96.33 C270495,76 D 149 + 96.97 E 174 + 96.54 4 months A 213 97.80 B 21g 196.83 g 149 + 97.33 * Thiourea measurements were taken for 1 month and 2 months, and on the 19th for 3 months. This was done once a week, and then once a day thereafter.

※※ In Section C, the thiourea reading changed from zero to positive in the middle of the two-month period. It was.

14 1 402 115 415 121 2 433 134 406 105 3 409 92 399 124 4 485 92 389 129 5 410 134 282 86 6 335 66 346 101 7 4.39 75 421 114 8 557 58 452 123 9 469 61 389 101 *Pronunciation: Asaruni Inkoboretei) ゛'s Amarillo 脣t: Ren Tankha It was held in U.S.

Tokuho 060-500453 (5) FIG.2 international search report

Claims (1)

[Claims] 1. Prepare an electrolytic solution for copper scouring consisting of an aqueous solution of sulfuric acid and copper sulfate at an effective concentration, and The solution contains a large number of additives, one of which is thiourea, which is a p1# electrolyte. The influent and effluent streams of the electrolyte pass through the influent and effluent stream conduction means during refining. in suitable container means with both the thioureas and the effluent stream; Total influx of thioureas in an amount sufficient to maintain the concentration at least above the trace concentration. Add to the liquid stream: and electrolytically refining copper in the vessel means; The most important method of electrolytic refining of steel. 2. Concentration of thioureas in the electrolyte in the effluent stream? υ In the short term with effective measurement methods 2. The method according to claim 1, wherein: 3. The method according to claim 2, wherein the measuring means is differential pulse polarography. Method. 4. The claim that the minimum concentration of thioureas in the effluent stream is about 100 ppb. The method described in paragraph 1. 5. The desired range of thioureas concentration in the effluent stream is about 100-5000 ppb The method according to claim 1. 6. The method according to claim 1, wherein the container is a tank house for copper refining.