Coppers cleaning

F). To prevent degradation it is necessary to take account not only of the stability or instability of a compound but also of questions such as the period of time at the temperature, whether oxygen is present or the surrounding atmosphere is inert, and what materials are in contact with the plastic. As an example of the last, copper causes rapid degradation of polypropylene, and therefore copper cleaning pads should not be used on equipment for processing this material. 

To address all these factors, an improved copper cleaning chemistry has been developed by Hoppe, et al. Designed to replace an effective, but overly aggressive concentrated nitric acid etch, this peroxide-based method allows for more controlled cleaning of surfaces. 

Statuary finishes on copper. Clean the copper with pumice and water or pumice and solvent to remove all dirt, grease, oil, and tarnish. Brush the entire surface with a 2% solution of liquid ammonium sulfide in water. Once dried, the color can be evened out by rubbing lightly with pumice and water, using a stub or fine brass wire brush. 

CR-10, along with most other copper cleaning solvents and most household cleaners, contains ammonia. Ammonia helps remove the copper but attracts moisture. This can cause the cleaned steel to quickly rust... 

The behavior in the presence of air is quite different. For example, Tingle [22] found that the friction between copper surfaces decreased from a fi value of 6.8 to one of 0.80 as progressive exposure of the clean surfaces led to increasingly thick oxide layers. As noted by Whitehead [23], several behavior patterns... 

The cleaning or depassivation eflect is of great importance in sonoelectrochemistry, as it can be employed to wash off surface-adsorbed species and reduce blocking of the electrode by adsorption of reaction products. This eflect has been reported, for example, for the depassivation of iron electrodes and for the removal of deposits and in the presence of polymer films on the electrode surface. However, damage of the electrode surface, especially for materials of low hardness such as lead or copper, can also occur under harsh experimental conditions and applied intensities [70, Tf, 80]. 

Place 50 g. of o-chloronitrobenzene and 75 g. of clean dry sand in a 250 ml. flask equipped with a mechanical stirrer. Heat the mixture in an oil or fusible metal bath to 215-225° and add, during 40 minutes, 50 g. of copper bronze or, better, of activated copper bronze (Section 11,50, 4) (1), Maintain the temperature at 215-225° for a further 90 minutes and stir continuously. Pour the hot mixture into a Pyrex beaker containing 125 g. of sand and stir until small lumps are formed if the reaction mixture is allowed to cool in the flask, it will set to a hard mass, which can only be removed by breaking the flask. Break up the small lumps by powdering in a mortar, and boil them for 10 minutes with two 400 ml. 

COALCONVERSIONPROCESSES - CLEANING AND DESULFURIZATION] (Vol 6) -use of cast copper alloys with [COPPER ALLOYS - CAST COPPER ALLOYS] (Vol 7)... 

Monel and nickel are the preferred materials of constmction for cylinders and deHvery systems however, copper, brass, steel, and stainless steel can be used at room temperature, providing that these metals are cleaned, dried, and passivated with a fluoride film prior to use. Studies have shown that fluorine passivation of stainless steel and subsequent formation of an iron fluoride layer prior to WF exposure prevents reaction between the WF and the stainless steel surface (23). 

Mercury spills should be cleaned up immediately by use of a special vacuum cleaner. The area should then be washed with a dilute calcium sulfide solution. Small quantities of mercury can be picked up by mixing with copper metal granules or powder, or with zinc granules or powder. To avoid or minimize spills, some plants use steel trays as pallets so that a spih, whether of mercury or a mercury compound, is contained on the steel tray. 

The primary environmental concern for the coating plant is actually the residual material on the anode stmctures being returned for recoating. Therefore the anode user must enact effective cleaning procedures prior to shipment. For example, anodes in chlorine use must be cleaned of all traces of mercury and asbestos (qv). Anodes used in electrogalvanizing or in copper-foil production must similarly be cleaned to remove all traces of process materials. If cleaning at the user s plant is not done effectively, the anode may well be shipped back to the user for appropriate action before it is considered for recoating. 

Molten tin wets and adheres readily to clean iron, steel, copper, and copper-base alloys, and the coating is bright. It provides protection against oxidation of the coated metal and aids in subsequent fabrication because it is ductile and solderable. Tin coatings can be appHed to most metals by electro deposition (see Electroplating). 

AHoy scrap containing tin is handled by secondary smelters as part of their production of primary metals and alloys lead refineries accept solder, tin drosses, babbitt, and type metal. This type of scrap is remelted, impurities such as iron, copper, antimony, and zinc are removed, and the scrap is returned to the market as binary or ternary alloy. The dross obtained by cleaning up the scrap metal is returned to the primary refining process. 

The patented wire is again cleaned with acid, rinsed, and brass plated just before the second drawing. The brass acts as a drawing lubricant and as well as an adhesive to mbber. The brass composition is typically 60—70% copper with 2inc as the remainder. The patented, brass-plated wire is drawn into filaments of 0.15—0.38 mm diameter. 

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