Cupric Chloride Sulphate

Tantalum has excellent resistance to virtually all salts including chlorides (especially cupric and ferric chloride), sulphates, nitrates and salts of organic acids, provided (a) they do not contain fluorides, fluorine and free sulphur trioxide, or (b) hydrolyse to produce strong alkalis. 

Aluminium sulphate Ammonium bifluoride Ammonium bisulphite Ammonium bromide Ammonium persulphate Antimony trichloride Beryllium chloride Cadmium chloride Calcium hypochlorite Copper nitrate Copper sulphate Cupric chloride Cuprous chloride Ferric chloride Ferric nitrate... 

By the action of ammonia on cuprous or on cupric salts, substances are formed containing varying amounts of ammonia. Cuprous ammines arc colourless, unstable, and readily turn blue, passing into the more stable cupric ammines. The cupric ammines are deep blue in colour and dissolve in water, yielding dark blue solutions. In the dry state many of them arc stable. The most important ammines of copper are those of the salts, cupric chloride and cupric sulphate. 

Anhj drous cupric chloride, like anhydrous cupric sulphate, absorbs ammonia rapidly the absorption is accompanied by increase in bulk, and the brown chloride changes to a blue powder having the composition CuCl2.6NtI3. The following compounds of cupric chloride with ammonia are known —... 

Hydrofluoric acid like water is an associated liquid, and even the gas, as we shall soon see, is associated. It has the power of uniting with fluorides. It also seems to be an ionizing solvent for a soln. of potassium fluoride in liquid hydrogen fluoride is an excellent conductor it also possesses marked solvent powers. According to E. C. Franklin,7 the liquid readily dissolves potassium fluoride, ehloride, and sulphate sodium fluoride, bromide, nitrate, chlorate, and bromate acetamide and urea. The solvent action is not so marked with barium fluoride, cupric chloride, and silver cyanide while calcium and lead fluorides copper sulphate and nitrate ferric chloride, mercuric oxide, and magnesium metal, are virtually insoluble in this menstruum. Glass also is not affected by the liquid if moisture be absent. The liquid scarcely acts on most of the metals or non-metals at ordinary temp., though it does act on the alkali metals at ordinary temp., much the same as does water, with the simultaneous production of flame. 

In the modern Hunt-Douglas process the ore is leached with dilute sulphuric acid, and the copper converted into cupric chloride by addition of ferrous chloride or calcium chloride. The use of the calcium salt entails removal of the calcium sulphate by filtration. The cupric salt is precipitated as cuprous chloride by reduction with sulphur dioxide, and the precipitate is converted into metallic copper by treatment with iron, or into cuprous oxide by the action of milk of lime. In this process the amount of iron needed is proportionately small, ferric hydroxide is not precipitated, and silver is not dissolved. 

When the ore contains cuprous sulphide this salt is converted into a soluble form cupric sulphate, soluble in water cupric oxide, soluble in hydrochloric or sulphuric acid cupric chloride, soluble in water, or cuprous chloride, soluble in solutions of metallic chlorides. 

The formation of the chlorides is effected in the dry way by calcination with sodium chloride or in the wet way by interaction with ferrous chloride and hydrochloric acid or with ferric chloride. The wet way is only adopted if fuel is scarce, or the escape of noxious vapours into the atmosphere is not permissible. In the dry method the ore is oxidized by a preliminary roasting, and then chloridized by calcination with sodium chloride or Abraum salts in a furnace of the reverberatory or muffle type, the principal product being cupric chloride. The Dotsch modification of the wet process, worked at Rio Tinto, depends on the action of ferric-chloride solution on a mixture of the ore with sodium sulphate and ferric chloride. The liquid drawn off from the bottom of the heaps of ore contains cuprous chloride in solution as a complex salt. The copper is liberated by the action of iron, the ferrous chloride simultaneously formed being chlorinated in towers to ferric chloride, and the product employed for moistening the heaps of ore. 

Refining by other Methods.—Various other methods are available for the purification of copper. An example is the ready reduction of cuprous chloride by soft iron, a substance without action on cupric chloride. Aluminium slowly reduces a warm solution of cupric sulphate. Vigoroux 4 recommends a method depending on the action of aluminium on a solution of copper in concentrated hydrochloric acid. 

Sulphur dioxide precipitates the chloride from an aqueous solution of cupric sulphate and sodium chloride. After being washed with dilute sulphurous acid, and then glacial acetic acid, the salt can be dried by the aid of heat.4 The reduction of a solution of cupric chloride, with formation of cuprous chloride, can also be-effected by means of phosphorous acid.5... 

The copper can first be converted into cupric chloride by the action of chlorine and water. With sulphuric acid the salt formed reacts to produce cupric sulphate. and hydrochloric acid.9... 

Complex salts of cupric sulphate with cupric chloride, potassium sulphate, and potassium chloride have been described.2... 

In alkaline solution oxidation of ferrous iron is fairly rapid,8 but certain acids retard the reaction. Ferrous sulphate, for example, in the presence of free sulphuric acid, is very stable in air. Concentrated hydrochloric acid assists the oxidation, as also do traces of certain substances, such as platinic and cupric chlorides, palladium nitrate, etc.9... 

Materials Fehling s solution, solutions of glucose, of cupric chloride, of cupric sulphate, of potassium iodide, concentrated hydrochloric acid, copper filings, starch. 

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