Copper electrolytic

Selenium is found in a few rare minerals such as crooksite and clausthalite. In years past it has been obtained from flue dusts remaining from processing copper sulfide ores, but the anode metal from electrolytic copper refineries now provide the source of most of the world s selenium. Selenium is recovered by roasting the muds with soda or sulfuric acid, or by smelting them with soda and niter. 

Control and signal cables are made up of fine copper wire strands of plain electrolytic copper wire with PVC or EPR-based insulation and an outer jacket of special PVC or ethylene copolymers. 

Values are minimum for the primary metal and maximum for impurity concentrations. Oxygen-free electrolytic copper containing 0.0001 wt % Bi and Cd and 0.00005 wt % Mn. 

Manufacture and Recovery. Electrolytic copper refinery slimes are the principal source of selenium and its sister element, tellurium, atomic numbers 34 and 52, respectively. Electrolytic copper refinery slimes are those constituents in the copper anode which are not solubilized during the refining process and ultimately accumulate in the bottom of the electrorefining tank. These slimes are periodically recovered and processed for their metal values. Slimes generated by the refining of primary copper, copper produced from ores and concentrates, generally contain from 5—25% selenium and 2—10% tellurium. 

J. E. Hoffmann, "Recovery of Selenium from Electrolytic Copper Refinery Slimes," in V. Kudryk, D. A. Corrigan, and W. W. Liang, eds.. Precious Metals Mining Extraction and Processing H, TMS, Warrendale, Pa., 1983. 

Most commercial tellurium is recovered from electrolytic copper refinery slimes (8—16). The tellurium content of slimes can range from a trace up to 10% (see Seleniumand selenium compounds). Most of the original processes developed for the recovery of metals of value from slimes resulted in tellurium being the last and least important metal produced. In recent years, many refineries have changed their slimes treatment processes for faster recovery of precious metals (17,18). The new processes have in common the need to remove the copper in slimes by autoclave leaching to low levels (<1%). In addition, this autoclave pretreatment dissolves a large amount of the tellurium, and the separation of the tellurium and copper from the solution which then follows places tellurium recovery at the beginning of the slimes treatment process. 

J. H. Schloen and E. M. Elkin, Trans. ATME 188, 764 (1950) A. Butts, ed.. Treatment of Electrolytic Copper Eefmery Slimes, Reinhold Publishing Corp., New York, 1954, Chapt. 11. 

Copper powder—Cl Pigment Metal 2, Cl No. 77400. A very fine free-flowiag metallic powder prepared from virgin electrolytic copper [7440-50-8]. It contains small amounts of stearic or oleic acid as a lubricant. 

Electrowinning. Vat leaching often yields copper solutions having concentrations sufficiently high for direct electrowinning. However, high concentrations of cations other than copper and low copper concentrations make it more difficult to obtain high purity electrolytic copper by direct electrolysis of leach solutions than by electrolysis of purified solutions obtained from solvent extraction. 

Purity. Electrolytic copper is one of the purest of the materials of commerce. The average copper content of ETP copper, for instance, is over 99.95%, and even the highest level of impurities other than oxygen are found only to the extent of 15—30 ppm. Up to 0.05% oxygen is present in the form of copper(I) oxide. Even at these low impurity levels, properties of interest to fabricators are affected in varying degree. 

The process consists of pre-etching, etching, etch neutralization, catalyst appHcation, catalyst activation, and plating. Most commercial appHcations, except REl/EMl shielding, use the initial copper or nickel deposit as a base for subsequent electrolytic plating of electrolytic copper, nickel, or chromium. The exact types and thicknesses of metal used are determined by part usage, eg, automotive exterior, decorative, plumbing, and others (24). 

Numerous variations exist in the electroless plating solutions, processes, and techniques employed both in laboratory and commercial form, to create a great variety of products (39). AH produce a layer of highly conductive copper in specified areas. Modem electroless copper films have a ductiHty and conductivity identical to that of electrolytic copper (40). The three basic classes of copper baths are... 

Fig. 2. Multilayer printed circuit board composite. Constmction is multiple layers of epoxy—glass and foil copper. Foil copper outermost layer and drilled through-holes are sequentially plated with electroless copper, electrolytic copper, electroless nickel, and electroless gold.

Carefully polished electrolytic copper 176 0.018 Electroplated on pickled iron, not ... 

Elektrolyt-kupfer, n. electrolytic copper, -nickel) n. electrolytic nickel, -silber, n. elee trolytic silver, -zinn, n, electrolytic tin. elektromagnetisch, a. electromagnetic. Elektromagnetismus, m. electromagnetism, elektro-mechsnisch, a. electromechanical. 

Electroless nickel baths are usually preferred to electroless copper, since they tend to be more stable and are less likely to deposit metal on unwanted areas, such as plating racks. Electrolytic copper is then plated before the final application of nickel and chromium, where this is the required finish, as it... 

Thus the net effect of electrolysis is to transfer copper metal from the impure blister copper used as one electrode to the pure copper sheet used as the other electrode. Electrolytic copper is 99.95% pure. 

Figure 22. Practical 2000-A anode. Features include 108 channels and/or grooves, YBD carbon impregnated with epoxy, electrolytic nickel plate on carbon, electrolytic copper plate on nickel, copper wool packing, and central copper conductor. The anode is 20 cm in diameter and 120 cm long. (Reproduced with permission from paper 933 presented at the May 1997 meeting of The Electrochemical Society in Montreal.)...

Schlitte, F., Eichkom, G. and Fischer, H. (1968) Rhythmic lamerllar crystal growth in electrolytic copper deposition. Electrochim. Acta, 13, 2063—2075. 

Apart from the two classifications described above, electrolytes may also be classified according to the number and valence of the ions produced. Thus, sodium chloride and copper sulfate may both be termed binary electrolytes since one molecule of each of these chemical substances is capable of producing two ions. In the case of sodium chloride, both the ions produced are univalent so that this substance may also be called a uni-univalent electrolyte. Copper sulfate, however, yields two bivalent ions and so may be called a bibivalent electrolyte. The valences of the ions are quoted in the positive-negative sequence. Calcium chloride and potassium sulfate are both ternary electrolytes since one molecule of each yields three ions the former is bi-univalent, whilst the latter is uni-bivalent. 

It represents the case of the reaction at the metal electrode in which ions of the same metal discharge at the electrode from the electrolyte. It can be said that copper ions in the electrolyte (copper sulfate solution) possess a free energy GCu(ej, and those in the copper metal electrode possess a free energy Ci(ll(-ril.. Then, if a copper ion is to leave its place in the copper sulfate electrolyte structure and occupy a position in the structure of the copper electrode, the free energy change accompanying this process will be ... 

Block B shows the electrolytic copper recovery cell, which recovers metallic copper and regenerates sulfuric acid from the metal salts in the hot sulfuric acid pickle solution. It was originally felt that trace metals (zinc, tin, lead) would interfere with the recovery of pure copper. By controlling current density at 50 to 100 A/m 1 2 3, however, pure copper can be recovered while maintaining the copper concentration in the pickle bath at 15 g/L. 

The secondary pickle reservoir is also shown in Block B. Copper sulfate accumulates in this bath and eventually crystallizes out. These crystals can be recovered and sold as a copper-rich sludge or added to the electrolytic copper recovery loop. 

Electrolytic copper refining Blister copper Process wastewater Slimes containing impurities such as gold, silver, antimony, arsenic, bismuth, iron, lead, nickel, selenium, sulfur, and zinc... 

Stripping characteristics and the production of copper sulfate crystal, saturated copper sulfate solution, powdered copper, or electrolytic copper from the strip liquors... 

To produce electrolytic copper for evaluation of product quality... 

Tellurium dioxide in its orthorhombic form occurs in nature as mineral tellurite. It is mined from natural deposits. Also, tellurium dioxide is produced as an intermediate during recovery of tellurium metal from anode shmes of electrolytic copper refining (See Tellurium, Production). The dioxide also is prepared by treating tellurium metal with hot nitric acid to form 2Te02 HNO3. The product then is heated to drive off nitric acid. 

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