DE529903C - Iron removal from copper salt solutions containing ferrous salts - Google Patents

Description

When processing metallurgical lyes, in particular "those like those used in the Leaching of the burnup of copper gravel can be obtained on copper sulphate it is necessary to remove the iron by precipitation before the copper sulfate crystallizes. For this purpose, the bivalent iron present must be oxidized before precipitation will.

ίο According to the invention, the removal of the Made of iron by oxidation and precipitation as a basic salt in an acid medium, whereby a pH of 3.4 is not exceeded. Such oxidizing agents come here in use, which by itself does not change the hydrogen ion concentration the solution to be cleaned. Such oxidizing agents are for example air, chlorine gas, persulfates, nitrites. By adhering to a certain Hydrogen ion concentration during oxidation falls into the trivalent Transferred iron immediately as a basic salt, without, however, accompanying metals, such as copper, zinc, manganese, cobalt and others get into the iron precipitate.

The use of air as an oxidizing agent, which has also been common up to now, is with great importance Disadvantages, because the oxidation proceeds very slowly, with little use the blown air and the accumulation of poorly filtering precipitates, and if the addition of larger amounts of precipitant accelerates the process the oxidation process is aimed at, considerable losses of valuable components, especially copper. If the pn limit specified above is adhered to, step such difficulties do not arise, the oxidation of divalent iron takes place so rapidly that in the course of a few hours 98 to 99 per cent of its total is easily removed will.

In order to shorten the oxidation time, to achieve rapidly filtering precipitates and making good use of the air, it is of great importance to minimize the air bubbles to smash and to distribute in the liquid. The mixture of air and Liquid is expediently done by means of a centrifugal pump or one quickly rotating paddle stirrer. An advantageous embodiment of the method consists in the precipitation of the iron in a pointed kettle, with part of the lye constantly being pumped around is continuously withdrawn by continuously withdrawing liquid from the upper part of the pointed kettle and is reinserted in its lower part. The air supply is expedient shortly before the pump, in which an intimate mixture of air and Liquid takes place. It succeeds in this way, with five to six times the the amount of air theoretically required for the oxidation of divalent iron to get along, while hitherto an amount of air that has been increased several hundred times is required was.

In addition to the oxidation with air, it is possible to use a different one Connect the oxidizing agent, which further accelerates the process of oxidation connected is.

When using other oxidizing agents, such as chlorine gas, persulphate and the like, was so far worked in two phases by

only the transfer of the ferrous into the long-distance connections took place and finally the iron was precipitated by the addition of feces became. Here, too, the new way of working offers compliance with a specific pn limit considerable advantages by the oxidation and precipitation of the iron in a single operation can take place without the risk of major losses of accompanying metals.

The most favorable dosage of the precipitant in the de-ironing process for the individual case can be carried out regularly Easily determine ρ measurements. For example, the hydroxides or carbonates of the alkali or alkali metal precipitants Alkaline earth metals in question. If it is important that no foreign cation is present in the copper sulfate solution gets, the use of barium compounds offers special Advantages.

example 1

13Sol burn-up liquor, which during leaching sulfating roasted copper-containing gravel is obtained and in the liter

2i, 3ogCu j
2.73 g Fe ¹¹ > as sulfates 1.27 g FePiJ

_{contains, aragonite sludge with a content of 90% Ca Co 8 is} added at 80 ° while pumping around and blowing in 1.2 ebm of air per hour. The amounts of precipitant entered on the basis of pn measurements can be seen from the following table, which also gives the amounts of ferrous salt still remaining in the solution.

- To Oxidized Ph Registered hours Fen Aragonite mud ° / n - kg 0 - 2.3 18.5 I. 12th 3.1 2.1 2 27 3.0 1.0 3 52 3, o 4th 62 3.1 1.0 5 78 3.1 . 1.0 6th S ₇ 3.2 0.9 7th 94 3.1 8th 97 3.1 9 98

The iron precipitate contains only 1 per _{cent of} the total copper in the lye.

Example 2

In ioool burning liquor from sulphating roasted copper gravel, which per liter

² 3.7og Cu)
i, 6ogFe ⁿ [as sulfates 0.78 g Fem j
6.9OgH ₂ SO ₄

divalent

contains 92.7 ° / ₀ of the iron will be oxidized by air while maintaining a pH level from 3.1 to 3.2 within 6 hours, and precipitated. The remaining Fe ¹¹ is then oxidized and precipitated by 7.1 1 4 ⁰ I ₀ IgQ potassium persulphate solution while maintaining a pH of 3.1. After 15 minutes of Ferro content to 1.7%> ^nac h 30 minutes with 1 / declined ° _0th

The iron precipitate contains only 0.9% of the total amount of that contained in the lye Copper.

Example 3

1001 technical copper sulfate solution with a salary of

30 g Cu

liter

in .Liter are at 8o ° by means of 187 g 99.5% sodium nitrite is oxidized, the pH of the solution being kept at about 3.0 by adding dilute soda solution will. After a few minutes, the basic ferric sulfate formed is separated off. the Copper sulphate solution then contains only traces of iron, the iron precipitate less than 1% of the total amount of copper.

Claims (2)

Patent claims: i. Process for iron removal ferrous salt containing copper salt solutions using oxidizing and precipitating agents, characterized in that the iron is oxidized and precipitated as a basic sulfate in an acidic medium are in compliance with a pH value of not more than 3.4 and with the use of oxidizing agents, which do not by themselves change the hydrogen ion concentration of the solution to be oxidized. 2. Embodiment of the method according to claim 1, characterized by the use of air as an oxidizing agent and the mixing of air and Liquid in a centrifugal pump or by intensive agitation. BERLIN. OEDBUCKT IN DtfR HEICHSDHUCKEHE!