To remove copper

The copper-chelating abihty of sahcylaldoxime has been used to remove copper from brine in a seawater desalination plant effluent. A carbon—sorbate bed produced by sorption of the oxime on carbon proved to be extremely effective in the continuous process (99). In another apphcation, the chelating abihty of sahcylaldoxime with iron and copper was used to stabilize bleaching powders containing inorganic peroxide salts (100). 

If antimony and arsenic are present ia the feed, copper and iron react to form the respective antimonides and arsenides known as speiss (specific gravity 6.0). If it is preferred to remove copper ia a speiss layer, the sulfur ia the siater must be reduced and the addition of scrap iron may be necessary to encourage speiss formation. Matte and speiss are usually sent to a copper smelter for recovery of the metals. 

Sulfide Ores ores. In the Zairian ores, cobalt sulfide as carroUite is mixed with chalcopyrite and chalcocite [21112-20-9]. For processing, the ore is finely ground and the sulfides are separated by flotation (qv) using frothers. The resulting products are leached with dilute sulfuric acid to give a copper—cobalt concentrate that is then used as a charge in an electrolytic cell to remove the copper. Because the electrolyte becomes enriched with cobalt, solution from the copper circuit is added to maintain a desirable copper concentration level. After several more steps to remove copper, iron, and aluminum, the solution is treated with milk of lime to precipitate the cobalt as the hydroxide. 

A number of solvents are used to remove copper and copper oxides. These are described in the following sections. 

The pentafluorophenylcopper tetramer is usually analytically pure as isolated and melts at 200° with decomposition. If any significant decomposition occurs during the final drying, the product can be purified by dissolution in ether, filtration to remove copper metal, and precipitation by addition of hexane. It can also be recrystallized from benzene. When kept in a sealed container under nitrogen at room temperature, pentafluorophenyl copper tetramer appears to be stable for reasonable periods. It can be stored indefinitely at -78° under an atmosphere of carbon dioxide. 

Some innovating treatment technologies may be introduced in the treatment of wastewater generated in the aluminum fluoride industry to make its effluent safer. The ion exchange process can be applied to the clarified solution to remove copper and chromium. At a very low concentration, these two pollutants can be removed by xanthate precipitation.24 A combination of lime and ferric sulfate coagulation will effectively reduce arsenic concentration in the wastewater. 

G. Gautier, M.P. Colomhini, GC MS Identification of Proteins in Wall Painting Samples A Fast Clean up Procedure to Remove Copper based Pigment Interferences, Talanta, 73,95 102 (2007). 

Citrosolv A two-stage process for removing deposits from steam boilers, using citric acid. The first stage uses ammoniated citric acid at pH 3.5 to 4 to remove iron oxide the second uses a solution containing more ammonia, pH 9.5 to 10, to remove copper oxide, and an oxidant such as sodium nitrite to passivate the surface. 

Hybinette A process for extracting nickel from sulfide ores. The nickel ore that occurs in Canada is a mixture of the sulfides of nickel, copper, and iron. Several methods have been used to separate these metals. In the Hybinette process, the ore is first smelted in a blast furnace, yielding a nickel-copper matte (i.e., a mixture of their lower sulfides). This is roasted to remove sulfur and leached with dilute sulfuric acid to remove copper. The resulting crude nickel oxide is used as the anode of an electrochemical cell. The nickel deposits on the cathode, which is contained in a cloth bag. Precious metals collect in the anode slime. The process was invented by N. V Hybinette in 1904 and operated at the Kristiansand refinery, Norway, from 1910. 

The mixture is cooled to room temperature, transferred to a 4-1. separatory funnel, and washed with three 300-ml. portions of saturated brine, to remove copper salts, and three 300-ml. portions of 10% aqueous sodium hydroxide, to remove benzoic add (Note 6). The benzene solution is then washed with 150 ml. of brine and is dried over anhydrous sodium sulfate. 

At least three pesticide plants use priority pollutant metals separation systems in the United States [7]. One plant uses hydrogen sulfide precipitation to remove copper from its pesticide wastewater. The operating system consists of an agitated precipitator to which the H2S is added, a soak vessel to which sulfur dioxide is added, a neutralization step using ammonia, and a gravity separation and centrifuging process. Copper is removed from an influent level of 4500 mg/L to 2.2 mg/L. 

When the sulfide ore carroUite, CuS C02S3, is the starting material, first sulfides are separated by flotation with frothers. Various flotation processes are applied. The products are then treated with dilute sulfuric acid producing a solution known as copper-cobalt concentrate. This solution is then electrolyzed to remove copper. After the removal of copper, the solution is treated with calcium hydroxide to precipitate cobalt as hydroxide. Cobalt hydroxide is filtered out and separated from other impurities. Pure cobalt hydroxide then is dissolved in sulfuric acid and the solution is again electrolyzed. Electrolysis deposits metallic cobalt on the cathode. 

Alternatively, raw anode slimes are aerated with hot dilute sulfuric acid to remove copper. Slimes are then mixed thoroughly with sodium carbonate and roasted in the presence of sufficient air. Sodium selenate formed is leached with water. Hydrochloric acid is added to this selenate solution. Treatment with sulfur dioxide precipitates elemental selenium. Alternatively, the selenate solution is evaporated to dryness. Sodium selenate is reduced to sodium selenide by heating with carbon at high temperatures. Sodium selenide is leached with water. Air is blown over the solution. Selenide is oxidized to elemental selenium which precipitates. 

Filter fuel through a clay or molecular sieve to remove copper. 

When the mine was closed, water pumps in a 3,800 ft shaft were turned off and the pit was slowly filled [11]. It is now a mile long, a half mile wide, and about 900 feet deep. It is said to be one of the largest Superfund sites. The chemistry of the Pit is complicated, one may say unfavorable, and certainly challenging. The bench-scale project considered the possibility of using Octolig to remove copper and help pay for the process, but additional study would be needed [12]. 

A fourth application is a convenient assessment of the removal of a transition metal by a supported chelator vs sorption on the substrate. It appears that the supported chelators were able to remove copper ion in a quantitative manner, but a goodly proportion (83%) was removed by sorption on silica gel. In contrast, a Linde molecular sieve (alone) with fairly defined pores removed about half of the copper ion through sorption. 

The principles of the classical Jaulmes and Espezel (3, 96, 97) procedure are still used. To prevent copper-catalyzed oxidative changes, EDTA is added to remove copper (98). Isopropyl alcohol has the same effect (99). Colorimetric (78, 94, 100, 101, 102) and GLC (103, 104) procedures are becoming popular. 

Clean a copper disk with a diameter of 6 mm by dipping it in HNO3 solution (1 1) (to remove copper oxide) and rinsing it well with bi-distilled water. Then, solder a 6 cm long shielded wire to the middle of the disk. 

In the meantime, clean a copper disk with a diameter of 5.9 mm by dipping it for few seconds in 1 1 HNO3 (to remove copper oxide), rinse it well with bidistilled water, dry it with towel paper, and solder it to the female electric connector end with Sn wire (iii). 

A mixture of 20 g. (0.1 mole) of o-bromobenzoic add, 63 cc. of 10% potassium hydroxide solution, 20 cc. of ethyl alcohol, 40 cc. of 50% tripotassium arsenite solution, and a little freshly reduced copper is refluxed at 90-95° for twelve hours with constant stirring. The reaction mixture is filtered hot to remove copper, made add to Congo red paper with 20 cc. of concentrated hydrochloric add, and evaporated to dryness on a steam cone. The resulting residue is extracted with absolute methanol the methanol extract is evaporated to dryness, and the residue is washed with ether to remove salicylic acid and unchanged o-bromo-... 

Telluraxanthene Te,Te-Dichloridei 1.47 g (5 mmol) of telluraxanthene are dissolved in 50 ml of acetone, a solution of 1.40 g (11 mmol) of copper(II) chloride is added dropwise, and the resultant mixture is heated under reflux for 30 min. The mixture is then filtered to remove copper(I) chloride, the filtrate is poured into water, the mixture is filtered, and the solid is recrystallized from chlorobenzene yield 1.20 g (76%) m.p. 250-270°. 

Purified (1 + 30) perchloric acid for copper determination Add 10 ml of 5% APDC to 11 of (1 + 30) HC104. Mix, then extract the solution serially three times with 50 ml of MIBK to remove copper from the aqueous phase. 

The pure reddish brown solution is filtered to remove copper oxide, and the azosalicylic acid is precipitated at 80°C. by the addition of 15 per cent hydrochloric acid. The product is insoluble in water. The yield is about 28 grams, or 90 to 95 per cent of the theoretical amount. From 156 grams of pure chlorobenzoic acid, 230 grams of pure azosalicylic acid can easily be obtained, whereas with impure starting materials and incorrect reduction of the nitro compound, the yield may fall to less than half this value. 

Recently a new synthesis of homoporphyrins was discovered serendipitously by Smith and coworkers [19]. These investigators found that treating the unsym-metrically substituted a,c-biladiene salt 42 with copper (II) afforded the copper containing macrocycle 43. Attempts to remove copper with sulfuric add and trifluoroacetic acids resulted in ring expansion to the free-base homoporphyrin 44... 

Ammonia Ethylenediamine-tetraacetic acid (EDTA) Forms soluble complexes with copper ions Dissolves water scales at alkaline pHs To remove copper from large boilers For cleaning water systems without shutdown Expensive... 

---