FI62558B - FRAMEWORK FOR THE USE OF WASTE MATERIALS FROM THE KOBOLT- OCH / ELLER NIKELBESTAONDSDELAR UR MALMER - Google Patents

Description

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Republic of South Africa, South Africa (ZA) 73 / 2M8 (71) Anglo American Corporation of South Africa Limited, Johannesburg,

Transvaal, South Africa - South Africa (ZA) (72) Norbert Walter Hanf, Johannesburg, Transvaal, South Africa - South Africa (ZA) (7M Oy Jalo Ant-Wuorinen Ab (5lt) Method for valuing cobalt and / or This invention relates to a process for extracting valuable cobalt and / or nickel components from from the ore, which substance is preferably slurried in the extract solution after grinding to a bulk density of 10-50%, more suitably 40-50%.

Several methods are known for extracting cobalt and nickel constituents from ores. The general known method comprises using an ammonium carbonate extract solution. However, such extraction has the disadvantage that the substance must be treated in a pre-reduction step before extraction. It is also known to extract with sulphate and sulphamate extract solutions. Such an extraction has the disadvantage that at the same time a large amount of scrap mineral is extracted. In sulfate extraction, sulfate is sometimes prepared in situ using a sulfite solution and feeding oxygen or an equivalent oxidizing gas through it.

It is an object of the present invention to provide a process for extracting cobalt and / or nickel components from a substance containing one or both of these metals in an oxidized form, which process has some advantages over previously known processes.

2 62558

The process according to the invention is characterized in that the extraction is carried out with an extract solution containing ammonium sulphite, ammonium bisulphite or a mixture thereof in a predominantly non-oxidizing atmosphere, the pH of the extract solution being greater than 7, preferably in the range 8-10 and more preferably 25 ° C, more preferably 40- 60 ° C.

Ammonia and sulfur dioxide are evolved from the extract solution and these mainly produce a non-oxidizing atmosphere.

The extract solution can be prepared by feeding sulfur dioxide gas through an ammonia solution of the desired concentration until the desired pH is reached. Under basic conditions, sulfite ions predominate, while under acidic conditions, bisulfite ions dominate. However, it is preferable to work under basic conditions so that the extract solution has a high concentration of sulfite ions. The preferred pH of the solution is 8-10.

The concentration of ammonium sulfite, ammonium bisulfite or a mixture thereof varies depending on the substance, the concentration of nickel and / or cobalt in the substance and other similar factors. The expert can select the optimal concentrations for each use.

The substance is preferably an oxygen-containing ore containing one or both metals or manganese ore in the form of lumps mined from the ocean floor. In the case of manganese wafers, it has been found that by using the extraction leaches according to the invention, the nickel component is extracted to a considerable extent, while the manganese is extracted only to a small extent. This selective extraction of nickel is commercially very advantageous.

The substance is preferably in finely divided form, the powdered substance being slurried with ammonium sulphite solution. It has been found that the bulk density of the slurry, i.e. the weight ratio of the ore to the total weight of the slurry, does not significantly affect the extraction of the cobalt and / or nickel constituents. Suitable bulk densities are in the range of 10-50%, with a range of 40-50% being preferred.

It has been found that the regeneration of metal components, especially cobalt, increases significantly with increasing temperature. Thus, it is preferred to perform the extraction at a temperature above ambient temperature, i.e., above about 25 ° C. In particular, it has been found that temperatures of 3 62558 at 40-60 ° C give very satisfactory results.

The metal components of the formed extract solution, which are separated from the substance, can be recovered using conventional isolation methods such as extraction solvent, electrolysis, pressure reduction and the like.

The following examples illustrate the invention.

Example 1:

The lumpy manganese ore mined from the bottom of the Pacific Ocean was crushed into a fine powder. The wafers were found by analysis to contain about 39% Mn, 0.2% Co, 1.1% Ni, and 0.91% Cu, all percentages being by weight.

The crushed material was extracted with an ammonium sulfite extract solution containing 300 g / l ammonium sulfite and having a pH of about 10. The extract solution was prepared by bubbling sulfur dioxide gas through a commercial grade ammonia solution (25% by weight ammonia) until a pH of 10 was reached. / 1 ammonium sulfite.

For comparison, the same crushed material was extracted using ammonium carbonate extract solution according to the prior art.

This solution contained 4 moles of ammonia and 2 moles of ammonium carbonate per liter of solution and was prepared by bubbling carbon dioxide through a commercial grade ammonia solution.

In each case, the crushed cobs were mixed with the extract solution in a round-bottomed flask placed in a thermostatic bath set at 4 ° C. The slurry was stirred and the extraction was performed for a specified time. In the case of ammonium sulphite, the ammonia and sulfur dioxide formed formed a mainly non-oxidizing atmosphere.

The results are shown in Table 1 below

Table I

Extraction of Cu, Co, Ni and Mn from Mn beans

Extraction time Reagent Extraction (%) (t) Cu Co Ni Mn Remarks 2 AS 86.8 84.4 78.3 <0.1 ore as such 4 AS 92.0 84.3 89.9 <0.1 ore as such 4 AS 84.5 71.1 65.1 <0.1 pre-reduced ore 4 AC 89.1 63.2 76.5 <0.1 pre-reduced ore 4 AC 17.3 1, 2 <1 <0.1 ore it 11a 6a AS = ammonium sulphite solution (300 g (NH4) 2SOl, pH 10) AC = ammonium carbonate solution (4 moles NHg + 2 moles (NH4) liter)

It follows from the above that certain experiments were performed using a pre-reduced substance. The material was pre-reduced by heating at 700 ° C using 10% carbon for 1 hour in an airtight state. The reason for this is that it is already known that ammonium carbonate extraction takes place better with the use of a pre-reduced substance.

The results presented above show that ammonium sulfite extraction using cobalt and nickel extraction is significantly more efficient than ammonium carbonate extraction, especially when using ore as such. This makes the process according to the invention very advantageous because the reduction step incurs considerable costs for each process. It is also noted that manganese is extracted only in small amounts.

Example 2:

The copper-cobblite ore from Zaire was crushed to a fine powder (about 100% to 100 mesh) and slurried with ammonium sulfite lithium extract solution in a round bottom flask placed in a thermostatic bath set at 45 ° C.

The ammonium sulfite solution was prepared in the same manner as described above by bubbling sulfur dioxide gas through commercial grade ammonia. The bubbling was adjusted to give a solution with a pH of about 9.5 containing 9.2 moles of ammonia and 2.5 moles of sulfur dioxide per liter of solution.

The slurry had a bulk density of 10% and the slurry was agitated using a conventional agitator.

Under these conditions, 90% of the copper and 50% of the cobalt were extracted in 15 minutes. After one hour, only slightly more copper could be extracted while much more cobalt could be extracted. After two hours, about 75% of the cobalt had been extracted.

Similar experiments were performed using the same conditions but different mass densities. The pulp densities used were 20%, 50% and 100%. In all cases, it was found that good copper and cobalt extraction was achieved after about 2-3 hours.

Example 3:

For comparison, extraction of cobalt constituents was performed 5,62558

From Zaire ore using ammonium sulphite and ammonium carbount extract solutions.

Extract solutions were prepared in the same manner as described in Example 1. The ammonium sulfite solution had a pH of about 9.0 to 9 and contained 2 moles of ammonia per liter and 5 moles of sulfur dioxide per liter. The ammonium carbonate solution contained 8 moles of ammonia per liter and 2 moles of carbon dioxide per liter of solution.

The crushed ore corresponding to Example 2 was slurried with the extract solution in a round-bottomed flask kept at * + 5 ° C in a thermosate bath. The bulk density was 50% in all cases.

After 3 hours of extraction, it was found that 90% of the copper and 65% of the cobalt had been extracted using ammonium sulfite extract solution.

Using ammonium carbonate extract solution, it was found that only 81% of the copper and 51% of the cobalt had been extracted in the same time.

When extracting the Zaire ore, it was found that only small amounts of temporal alkaline earth metal scrap products had been extracted.