DE214811C - - Google Patents

Description

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IMPERIAL

PATENT OFFICE

The invention relates to a process for the extraction of pure copper by from a solution of copper sulphate starts out, which is prepared by one of the usual methods ; has been. ,

, '. It is known that the method for Aus ■ ■■■ '·. separation of copper from its ores; the r · jauf so-called; wet NVege works, in it ν; consists; 'that.: ·; man: that depending on the circumstances : ^ o the either roasted or; leaches or extracts unchanged ore using a suitable solution capable of dissolving the copper; In this way the copper is mostly obtained in the form of a sulphate.
The otherwise very impure copper solution that is obtained in this way can be treated in various ways in order to precipitate metallic copper from it. The most common method, however, is to precipitate the copper from the solution by adding Iron waste in contact, brings. While the iron goes into solution, the copper in the form of so-called "cement copper" is precipitated. In ^: this form, the copper is extremely impure and must be further dry-treated for the purpose of refining and refining.

In contrast, in the method according to the invention, the treatment with 'iron, 30. which is tedious and costly. Is through replaces a single, very simple treatment which enables copper of great purity to be treated immediately. to receive. ,

The new method is based on the following principle, which was first recognized by the inventor zip justified:

If copper sulphate is heated in a closed vessel and under pressure in the presence of sulphurous acid at a temperature of at least 140 ^° , the copper salt is reduced to pure, metallic copper, while the sulphurous acid is oxidized and converted into sulfuric acid.

The implementation of the procedure is very simple.

If, for example, one takes a solution of copper sulphate, which comes from the leaching or extraction of the ore, it is sufficient to dissolve a certain amount of sulphurous acid in this solution and then to introduce the liquid prepared in this way into a copper or iron kettle, which, for example, is inside Lead is covered, after which at a temperature which is higher than 140 ⁰ C, but preferably in the vicinity of 170 ⁰ C., and heated under pressure.

The reaction is very quick and you win that way at the same time Time precipitated copper and sulfuric acid.

It can be the result of the action expressed by the following chemical equation: ...; .

SO ₄ Cu + SO ₂ -f 2H ₂ O -fu -f 2SO ₄ A _2. '

It has been suggested earlier to treat solutions of copper salts by means of sulphurous acid and with the application of "-.-. Heat, but they went along with it

ίο the heating never above the boiling point of the solution, ie, never more than 100 ⁰ C, and the reaction then not caused the formation of metallic copper, but merely of copper salts, generally of sulfites. If one wanted to extract metallic copper using this process, one had to use another reducing agent in addition to the sulphurous acid, such as iron oxide, and a mixture of copper salts and metallic copper was then obtained.

In contrast, the new process enables copper to be used in ^; To obtain the shape of metallic copper, and experience has shown that the yield of copper using the new process is greater, the higher the temperature is used, and that with otherwise the same degree of concentration of copper sulfate, since the. Yield decreases with the increase in the degree of concentration.

The figures below show how the yield increases with temperature, based on a concentration of 25 g copper per liter:

T

140 ° C.

ιό? ⁰ G.
190 ° C.

47 percent,

65 -

79 -. ·

This shows the advantage of using the highest possible temperatures.

However, if you work with solutions that are saturated with sulphurous acid, it increases the pressure with the temperature not only due to that of the liquid and the temperature corresponding vapor tension very quickly, but also as a result of the overpressure, whichever originates from the gaseous sulfurous acid.

To be able to use high temperatures without fear of excessive pressure must, one diminishes the last-mentioned cause either by going into the Solution only to the: theoretical equation Corresponding amount of sulphurous acid, introduced without waiting for saturation, and then gradually heated, or also by man

first heat the solution free of sulphurous acid and then heat the sulphurous acid in, gaseous states and under pressure, in. theoretically calculated amount little by little to the extent of the conversion into sulfuric acid. ! 65

The copper obtained in this way is very pure and often has a content of more than 99.90 percent pure copper. This is due to the fact that besides the precious metals (gold and silver), which may be combined with copper can, not a single one of the base metals; which usually accompany the copper, under the specified conditions. ■

Instead of sulphurous acid one can also use sulphites, which in this case iiy Skip sulfates. -;

Replacing the sulphurous acid with a sulphite is also a means of increasing it the yield at otherwise the same temperature, with the only pressure present which corresponds to the tension of the vapor created from the liquid. One can z. B. use the neutral or the acidic ammonium sulfite. If ammonium sulfite is used Once applied, the mentioned reaction takes place according to the following equation:

CuSO ₄ + (NHJ ₂ SO ₃ + H ₂ O = Cu + 2NH ₄ HSO ₄ .

To show the importance of this replacement of the sulphurous acid by a sulphite, the following numbers are given, referring to the same conditions and to a Concentration of 25 g copper per liter and a temperature of 180 ° C .; draw: '■ ■ j

Amount of copper obtained j

when using sulphurous acid 70 percent! when using ammonium sulfite 90

The copper produced under these conditions is absolutely pure and free of copper sulfite or · Oxide.

If you use ammonium sulfite, you can easily get it in the way that the sulphurous acid produced during the roasting of the ore is replaced by an ammonia! solution directs. You can do this consistently! by heating the developed in the process! recovered ammonium sulfate with a base such as lime.

The ammonium sulfate can also be used as am-

moniumbjsulfit by simply heating regene-j. : be rated .. · ■. ■ ·; ■ .. ■■■■■ \ .- ¹ Vv ■ _; t '■' ■ "'■'·;!?

■ ·· The new process is particularly advantageous] liable if sulfur ores are treated; should. If you roast (this, so 'ent-j The sulphurous acid necessary for the treatment is wound up, whereby the latter, due to the condensation;

I drive myself in in a very simple way j sulfuric acid, which is then used to: leach or extract the ores j can be used to prepare the copper sulphate solution j which will later be subjected to the treatment i should.

Claims (2)

Patent Claims: Si. Process for the extraction of pure ίο j copper from copper solutions by means of sulphur- I liger acid under heating and pressure, j characterized in that in a j closed container using j of pressure: and at a temperature that j ^{exceeds 140 0} C., the copper sulfate solution treated with gaseous sulphurous acid in an amount just about suffices to secure the reaction, with the sulphurous acid either a priori and, as stated above, added in an exactly predetermined amount, and then the solution is gradually heated or the introduction of the sulphurous acid into the aforesaid solution gradually happens until the aforementioned ratio of sulfuric acid is reached. 2. embodiment of the method according to claim i, characterized by the replacement sulphurous acid by sulphites (preferably ammonium sulphite). ;