Copper-ammonia solution washing process

The content of inert gas (Methane, Argon, Helium etc.) in the feed gas depends on the methods of gasification and purification for the feed gas. The copper-ammonia solution washing process is employed to purify the synthesis gas, which is produced by coal as the raw materials, the content of inert gas in the synthesis gas is generally from 0.5% to 1%, more than 1% with the methanation purification process and only a few ml-m with the methanol and liquid nitrogen wash purification process. 

Finally, one of the first continuous ion-exchange plants installed used a weak-acid resin to recover copper from rayon-fibre spinning solutions. In the Bemberg or copper(II) ammonium process,357 the spinning takes place in an addic copper sulfate solution, and the fibre is then washed in ammonia solution. The wash water contains as much as 30% of the copper required for the spinning operation and its recovery is important in economic and environmental terms. The copper is extracted as the cationic amine complex by the weak-acid resin, and is then stripped from the resin with the acidic spinning solution. Zinc is recovered in a similar manner from vicrose rayon-spinning operations. 

Place 200 cc. of concentrated ammonia (25 percent) and 50 cc. of water in a flask and conduct in hydrogen sulfide to saturation (closed flask). Divide the solution into two equal portions. Saturate the one with sulfur (60 g.) at 40°, filter, and add to the other half. Prepare a solution of 20 g. of crystallized copper sulfate in 200 cc. of water and add slowly and with constant shaking to the first solution until a permanent precipitate results (CuS). Filter as rapidly as possible through a large folded filter and bring the filtrate into an Erlenmeyer flask which is of a size to be nearly filled by the solution. By allowing the solution to stand, especially if cooled by ice, reddish crystals separate which should be filtered off the next day, washed with a little water and with alcohol, and dried over lime in a desiccator. To the mother liquor more copper sulfate can be added, and the process repeated. 

Although there are many techniques used to clean such objects, commercial products are often simple solutions of ammonia within a hydrogen-based solvent, with the additional inclusion of a very fine and mild abrasive called diatomaceous earth (DE). DE is nearly pure silica, in the form of SiO2, with a very porous characteristic. DE consists of the skeletons of small aquatic unicellular algal organisms called diatoms, which have survived evolutionary processes for approximately 100 million years. Placed in the taxonomic family Bacillariophyceae, the cell walls of these creatures are made of silica. Because silica is more dense than seawater or freshwater, the presence of silica tends to cause diatoms to sink into the water depths. As such, DE is collected from the bottom of ancient lake beds and is currently mined and used for many commercial and industrial purposes. Thus, within metal cleaners, DE acts as an abrasive, and the alkaline ammonia dissolves any greasy residue on the metalware. In addition, the ammonia reacts with the CuO or CuS to form the soluble ammonia complex of copper, which is Cu(NH3)42+. The greasy tarnish residue can then be washed away with clean water and a damp cloth. 

The solution is spun by the stretch-spinning process, i.e., it is carried away from the spin cone by warm water and drawn or stretched. The fiber is then washed free from copper and ammonia residues by an acid bath (7%H2S0J. 

The carbon dioxide was washed out of the process gas with water at high pressure and could eventually be recovered as a useful byproduct Residual carbon monoxide was usually removed with an ammoniacal copper solution before the final stage of ammonia synthesis. 

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