Decoppering

The principal Italian uses of Military BkPdrs are as igniters in percussion primers. For example, the Igniter of the 105/28mm cartridge case contd 25—30g of BkPdr ca 5g of lead foil, serving as a decoppering agent (Ref 28, p 345)... 

One of the most recent uses for Pb is the addition, in the form of foil or coil of wire, to propint pdr as a decoppering agent for the bore of the gun. The Pb is placed between the pro-pint charge and the projectile... 

Accdg to J.E. Capell, formerly of Pic-Arsenal, some other (than US or Russia) countries tried friction lubricants, but they did not think that they were of great value (See also Decoppering Agents in Vol 3, d D36-R)... 

Decoppering agents tin, lead-tin foil or lead compounds etc. 

Entkupferungsmittel. Ger for Decoppering Agent, such as described in Vol 3 of Encycl, p D36-R... 

Decoppering agent Lead or tin foil, compounds containing lead or tin Remove deposits of copper left by the driving band... 

Anticoppor]rig or Decoppering Agents. See under Fouling of Guns and Antifouling Agents... 

Some info on American decoppering agents, particularly of lead foil laminated to the cartridge bag is given in Refs 2 3... 

Decoppering additives used to decrease the buildup of copper residues in the barrel rifling include tin metal and compounds such as tin dioxide bismuth metal and compounds such as bismuth trioxide, bismuth subcarbonate, bismuth nitrate, bismuth antimonide. The bismuth compounds are... 

It was the first agent used to treat Wilson disease as a decoppering agent. It must be administered by intramuscular injection its use was all but abandoned in favor of orally available chelating agents. 

Auditory evoked brainstem potentials are helpful to document the degree of functional impairment and the improvement by decoppering treatment (Grimm et al., 1990 Grimm et al., 1992). 

Data on zinc in the treatment of Wilson disease are derived from uncontrolled studies using different zinc preparations (zinc sulfate, zinc acetate) at different doses (75-250 mg d ) (Ferenci, 1997). The efficacy of zinc was assessed by four different approaches. First, patients successfully decoppered by d-penicillamine were switched to zinc and the maintenance of their asymptomatic condition was monitored. Most patients maintained a negative copper balance and no symptomatic recurrences occurred. Some patients, however, died of liver failure after treatment was switched to zinc. Stremmel observed the occurrence of severe neurological symptoms in a 25 year old asymptomatic sibling 4 months after switching from d-penicillamine to zinc (Ferenci, 1997). 

If a decoppering agent is used for treatment, the compliance can be tested by repeated measurements of the 24 h urinary copper excretion. This approach is not useful if patients are treated with zinc. The dose of d-penicillamine can be lowered if in a compliant patient urinary copper excretion decreases over time and stabilizes at < 500 p g/day. Efficacy of treatment can be monitored by the determination of free copper in serum, and depending on the presenting symptoms. Liver disease can be assessed by routine liver function tests. Repeated liver biopsies with measurement of hepatic copper content are not helpful. Improvement of neurological symptoms can be documented by clinical examination or by auditory evoked brainstem potentials. In addition, some of the MRI abnormalities are fully reversible on treatment. 

It is often important in the study of a process to determine whether the limitations are governed by equilibrium or kinetic considerations. Sometimes it is possible to devise a design of the process or the equipment so that the apparent limitations set by equilibrium considerations are overcome. In this paper, detailed consideration is given to the lead refining processes of sulftir-decoppering and of vacuum dezincing to illustrate this, and possible implications for other refining processes are indicated. 

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