DE1483155B2 - - Google Patents

Description

The invention relates to a method for separating nickel, cobalt and iron from a solution which consists of these three ingredients and is used in particular in the purification of nickel.

In the process of cleaning the nickel, it is usually difficult to remove the cobalt impurities to separate. In the Shenitt-Gordon process, a typical, industrially used process, nickel ore is converted into sulphide, from the Nik- ίο kel is leached with ammonia at 70 to 90 ° C and under a pressure of 7 to 9 atmospheres. The thus obtained Nickel contains 1.75 to 2.8% cobalt.

When treating laterite ores, nickel must be separated from iron. After the nickel ore pulverized, reduced and treated with ammonia, nickel carbonate is precipitated from the lye. From this ammonia is removed with the help of a distillation.

Taking into account the fact that usually crude nickel etwa_l ° / ₀ contains cobalt as an impurity, has been developed a more convenient method for the elimination of cobalt and iron impurities in the course of the invention so as nickel ores with high purity.

According to the invention, nickel, cobalt and iron are made using a so-called gradual. Multi-stage extraction from a hydrochloric acid solution, which consists of these three substances, fractionated in one process step without back extraction becomes necessary.

The invention relates to a method for separating nickel, cobalt and iron from a hydrochloric acid Dissolution of these three substances through a gradual concentration multi-stage extraction, characterized by the following process steps:

a) Prepare a series of batches of an aqueous solution, each solution being a different one Concentration of hydrochloric acid as the extractant, the percentage of the hydrochloric acid concentration is gradually reduced from batch to batch and the mixed hydrochloric acid Solution of nickel, cobalt and iron introduced into the first batch of the aqueous series will;

b) Prepare another batch series with an organic one that is immiscible with water Extractant (organic batches), the tri-n-butyl phosphate diluted with carbon tetrachloride as the extractant, the concentration of the extractant in each Batch of the whole organic series is constant;

c) Mixing and shaking the first batch of the aqueous series and the first batch of the organic Series, subsequent settling and separating is an aqueous batch that is the Solute exchange has undergone once, and in an organic batch that is subject to the Has undergone exchange of dissolved substances once;

let d) mixing and shaking the aqueous batch from step c), the exchange of solutes has once undergone the second charge of the organic series, then Absitzen- ⁶ S, and separating in a first aqueous feed, which dissolved the exchange Has subjected fabrics twice, and in a second

45 organic batch that has undergone the exchange of dissolved substances once;

e) Mixing and shaking the first organic batch from step c) which is to be exchanged dissolved substances has been subjected once, and the second batch of the aqueous series, subsequent Allow to settle and separate into a first organic batch, which can be exchanged Solute has undergone twice, and in a second, aqueous batch that is undergoing the exchange has once undergone dissolved substances;

f) Mixing and shaking the first aqueous batch from stage d) which is to be exchanged Has undergone solute twice, followed by the third batch of the organic series Allow to settle and separate into a first aqueous batch, which is subject to exchange has undergone solute three times, and a third organic batch that is undergoing the exchange has once undergone dissolved substances;

g) Mixing and shaking the first organic batch from "Step d), which will be exchanged Solute twice, followed by the third batch of the aqueous series Allow to settle and separate into a first organic batch, which can be exchanged has undergone solute three times, and a third aqueous batch that is undergoing the exchange has once undergone dissolved substances;

h) gradual continuation of the mixing and separation stages, up to with each batch of a series the exchange of the solute with all batches of the another series has come to an end.

The organic extractants that can be used for this purpose are tri-n-butyl phosphate (TBP), Tri-n-octylphosphine oxide (TOPO), alkylamines and other anion extracting reagents. Watery Hydrochloric acid solutions are the three most useful cramming solutions. Will be common The extractant is diluted with carbon tetrachloride to make it face a heavy lower layer the aqueous hydrochloric acid phase forms in the separation apparatus.

The drawing and specific examples described on the basis of these are used for further explanation of the invention: Herein shows

F i g. 1 a schematic representation of all operations of the extraction process according to the invention,

F i g. 2 an example of the results obtained with this procedure,

F i g. 3 another example of the results obtained with this method and

F i g. 4 further examples of the results achieved with the method according to the invention.

F i g. 1 shows a schematic representation of all operations of the extraction method according to the invention. The first aqueous batch consists of an aqueous hydrochloric acid solution which contains the substances to be separated nickel, cobalt and iron. The following batches consist of hydrochloric acid solutions with successively decreasing acid strength. These batches of hydrochloric acid solution are designated with the numbers 2, 3 ... η. The initial solution is successively with each of the - eight in the example shown - batches of the organic lower Layer shaken and then separated until it

is finally separated from the last organic phase.

The subsequent batches of dilute aqueous hydrochloric acid solution with successively decreasing Acid starch pass through the in the same way one after the other with respective shaking and separation Batches of the organic lower layer until an exchange of the dissolved in all organic batches Substances took place. They are then separated from the last organic phase. the called lower organic phase consists of tri-butyl phosphate, which is diluted with carbon tetrachloride is.

A discontinuous countercurrent apparatus is used for carrying out the process according to the invention or a mixer settler is used. The heavy organic liquid is called stationary phase added in each of the mixing cells before the countercurrent process begins; the organic liquid is mixed with the aqueous phase in each cell for a suitable period of time shaken. After phase separation, the upper solution is then transferred to a decanting chamber decanted and then introduced into the next mixing cell. At the same time will be the next Top layer solution batch; d. H. a batch of filling solution with a lower acidity in the first Mixing cell introduced.

The conditions of tests carried out in practice are listed in the table. In the trials 1 and 2 were carbon tetrachloride solution using TOPO or alkylamine-HCl systems this extractant as a lower layer in a countercurrent apparatus with eight mixing cells of the

Introduced ίο Craig type. Trials 3 and 4 were performed using a TBP-HCl system. The organic extractant TBP must can be used undiluted as the stationary phase; consequently was due to specific gravity of TBP the stationary phase is the upper layer. To countercurrent treatment under this condition To carry out, six separating nozzles were used as mixing cells and the experiments were carried out by hand. In each case, the countercurrent hand-

ao development of the .gradual multi-stage extraction in principle carried out in such a way that one started with the initial sample solution and then successively with the filling solution the batches with graded hydrochloric acid concentration existed, as indicated in the table, was treated.

Ver
search
No. Output
Ni
(al angsma
(G)
Co
s chlorine material
Fe
id) Volume
orga
niche
solution en (ml)
water
rige
solution Organic batches
1.2: 8 fractions
3.4: 6 fractions Aqueous batches
1-5,6,7,8,9,10,11 Concentration of
aqueous solution
the filling hydrochloric acid
(n)
, 12, 13, 14-16-20 Decontamina
tion factor
by Co for
98% yield
on Ni +1 1 6.0 0.06 - 5.0 10.0 15% TOPO-CCl ₄ 8- »4- ^ 1- > H ₂ O ^ 2.02 · 103 +2 2 3.0 0.03 0.5 5.0 5.0 10 ⁰ Z ₀ TIOA-CCl ₄ 8 ^> 6- »4.1- > H ₂ O-> - +3 3 3.0 0.3 - 10.0 5.0 100% TBP 9- ^ 6- ^ 4- » - . 4th 0.5 0.5 0.5 15.0 5.0 +3
100% TBP 9 ^ 2 2N
-> HN0 ₃ -> -

+1 trioctylphosphene oxide.
+2 tri-isooctylamine.
+3 tri-n-butyl phosphate.

The results obtained are shown in FIG. 2 to 4 reproduced. In the figures, the amounts of cobalt and nickel are given with reference to the numbers of the aqueous fraction on a logarithmic scale. Results with a cobalt content of less than 10 ^-3 g / L have not been entered in the figures. The distribution of cobalt in Examples 1 and 2 and of iron was determined radiometrically with HiUe of cobalt-60 and iron-55.59 pens. The distribution of nickel and cobalt in Examples 2 to 4 was determined colorimetrically.

Examples 1 and 2

Nickel was found in the first fractions, cobalt in the following batches in hydrochloric acid solution. Like F i g. 2 shows, the nickel obtained in Experiment 1 was pure and free from cobalt. The decontamination factor was 2.02 ■ 10 ^3, in turn, can be estimated from the _0, the cobalt contamination in the purified nickel to less than 5 x 10 ~ ⁴⁰ /. As shown in the table, the amount of cobalt contained in the raw material with respect to nickel was I ⁰ I ₀ . The organic solution contained little after the experiment.

. Example 3 and 4

As shown in Figs. 3 and 4, nickel, cobalt and iron were obtained separately. the The organic layer contained little substance after the countercurrent treatment.

As can be seen from these results, the present invention provides the following improvements and advantages achieved:

a) Since the process can be started with a solution saturated with nickel chloride Nickel obtained as a concentrated aqueous solution from which the chloride can be easily crystallized can.

b) Since cobalt is obtained as an aqueous solution of cobalt chloride, the only excess Contains hydrochloric acid, the subsequent treatment is simplified.

c) Iron impurities contained in the raw materials become simultaneously removed from nickel and cobalt.

d) The organic layer can be used repeatedly for further treatments.

e) The method according to the invention can be carried out simply and reliably.

f) The inventive method has the feature on that pure nickel can be produced from raw nickel in an extremely effective manner can.

Claims (4)

Patent claims: 1. Process for the separation of nickel, cobalt _z0 and iron from a hydrochloric acid solution of these ■ three substances by a gradual concentration multi-stage extraction, characterized by the following process steps: a) Preparation of a series of batches of an * ⁵ aqueous solution, each solution having a different concentration of hydrochloric acid as the extractant, the percentage of the hydrochloric acid concentration being reduced gradually from batch to batch and the mixed hydrochloric acid solution of nickel, cobalt and iron in the first Batch of aqueous series is introduced; b) Prepare another batch series with an organic one that is immiscible with water Extractant (organic batches) that is diluted with carbon tetrachloride Tri-n-butyl phosphate is used as the extractant, the concentration of the extractant is constant in every batch of the whole organic series; c) Mixing and shaking the first batch of the aqueous series and the first batch of organic series, subsequent settling and separation into an aqueous batch, which has undergone the exchange of dissolved substances once, and into an organic one Batch that has undergone the exchange of dissolved substances once; d) Mixing and shaking the aqueous batch from step c), which is the exchange dissolved Substances underwent once with the second batch of the organic series, subsequent Allow to settle and separate into a first aqueous batch, which is subject to exchange Has undergone solute twice, and in a second organic batch that has become has undergone the exchange of dissolved substances once; e) Mixing and shaking the first organic batch from step c) which is to be exchanged has subjected dissolved substances once, and the second batch of the aqueous series, subsequent settling and separation into a first organic batch, which is the Has undergone exchange of dissolved substances twice, and in a second aqueous batch, which has undergone the exchange of dissolved substances once; f) Mixing and shaking the first aqueous batch from stage d) which is to be exchanged has subjected dissolved substances twice, and -the third batch of the organic "series, subsequent sitting down and severing 'into a first aqueous batch, which is subjected to the exchange of dissolved substances three times has, and a third organic batch that will be exchanging solutes once has undergone; g) Mixing and shaking the first organic batch from step d), which is the Has undergone solute exchange twice, and the third batch of aqueous Series, subsequent settling and separation into a first organic batch, which is broken up into the exchange Substances underwent three times, and a third aqueous batch that is undergoing the exchange has once undergone dissolved substances; h) Step-by-step continuation of the mixing and separation stages until one with each batch Series of solute exchange with all batches of the other series is over is led. 2. The method according to claim 1, characterized in, that tri-n-butyl phosphate (TBP), tri-isooctylamine or tri-octylphosphine oxide as extraction agents is used. 3. The method according to claim 1, characterized in that the extracting agent without dilution is used. 4. The method according to claim 1, 2 or 3, characterized in that the method with Carried out using a discontinuous countercurrent device or a mixer-settler will. 1 sheet of drawings