US2245503A - Manufacture of nickel carbonyl - Google Patents

Description

Patented June 10, 1941- I 2,245,503 MANUFACTURE or mcxar. caaaom Leo Schlecht, Rudolf Staeger, and Herman Klippel, Ludwigshafenon the Rhine, Germany, assiznors to I. G. Farbenindustrle Aktiengesellschaft, Germany Frankfort on the Main,

No Drawing. Application March 2, 1939, Serial In Germany March 12, 1938 2 Claims. (Cl. 23-203) The present invention relates to improvements in the manufacture of nickel carbonyl.

In the working up of nickel-copper matte for the recovery of nickel carbonyl, the ground matte has hitherto first been roasted until the sulphur has been removed as far as possible and the major portion of the copper then dissolved out with sulphuric acid from the roasted product. The nickel residue poor in copper is then reduced with watergas at about 400 C. and finally treated with carbon monoxide, the formation of nickel carbonyl thus taking place. I

In'the said process, the major portion of the copper must be removed by a special working operation. In order to avoid this drawback it has been proposed to use for the formation of carbonyl a matte of which the sulphur content has been reduced to such an extent in the smelting process by blasting that'in the smelted product at the most only the copper, in the form of cuprous sulphide, is combined with sulphur. Such a blasting process, however, causes waste of nickel.

by slagging.

Finally, attempts have also been ,made to reduce the original high sulphur content of nickelcopper mattes by admixture of finely divided metal, such as copper or iron powder. Considerable additional costs are occasioned, however, in the provision of the admixed metal in the necessary finely divided form. It has therefore been proposed to roast thoroughly 9. part of the matte,

or by reduction with gases in arotary tubular furnace. When carrying out the reduction in a way causing a furtherdecrease of the sulphur content left behind in the roasting stage, care should be taken that a correspondingly higher amount of sulphur remains in the roasting stage.

If the formation of carbonyl be carried out I under pressure, it is advantageous also to carry to mix it with another part of the unroasted matte,

to reduce the mixture and then to subject it to the treatment with carbon monoxide for the purpose of forming carbonyl. In this latter process, however, it is necessary to reduce as far as possible the sulphur content of the part to be roasted and this offers technical difliculties.

We have now found that all the said difliculties can be avoided by decreasing the sulphur content of the whole amount of matte, without previous removal-of the copper to such an extent by roasting that the copper and/or iron content of the roasted product is sufficient for binding the remalning amount of sulphur, reducing the partially roasted product and then subjecting it to the carbon monoxide treatment for the purpose of forming carbonyl.

The roasting, which is preferably carried out at about 800 0., offers no diilicul-ties because only the amount of sulphur which is most easily roasted off is to be removed.

The reduction of the roasted product may be carried out in different ways, for example by' fusing the mixture with carbon in a flame furnace out the reduction in the same pressure container under increased pressure with gases such as hydrogen. Very low temperatures, as for example 250 C., may be used, whereby a good reactivity of the nickel for the reaction with carbon monoxide to form nickel carbonyl is ensured.

Nickel-copper mattes of any constitution, in-

cluding those having a very high sulphur con-,

tent, maybe used as initial materials. Iron may ing should be carried so far that the ratio of iron to sulphur in the roast product is the same as in iron monosulphide. 'Thus, when workingaccording to our invention, the sulphur contained in the roasted and reduced product which is to be treated with carbon monoxide to form carbonyl, is in any case combined with copper and/or iron to sulphide, may be in the form of cuprous sulphide or of iron monosulphide or of both sulphides.

The following examples will further illustrate how the present invention may be carried out in practice, but the invention is not restricted to these examples.

Example 1 Nickel-copper matte having a content of 44.6 per cent of nickel, 33 per cent of copper, 0.6 per cent of iron and about 21 per cent of sulphur is roasted until the sulphur content has fallen to about 3 per cent. The roasted product is then treated in a high pressure furnace with flowing hydrogen in a cycle under a pressure of 200 atmospheres at 240 C. until no water separates when the hydrogen leaving the furnace is cooled. The hydrogen pressure is then allowed to subside and the temperature in the high pressure furnace is allowed to fall to about 100 C. At this temperature carbon monoxide is allowed to flow into the furnace and the pressure of the carbon monoxide is slowly raised to 200 atmospheres and the temperature to about 200C. The nickel carbonyl formed is separated in liquid form from v the gas leaving the furnace by cooling and the roasted product is converted into nickel carbonyl.

Example 2 Nickel-copper matte having a content of 47.28 per cent of nickel, 26.07 per cent of copper, 2.57 per cent of iron and 22.4 per cent of sulphur is roasted until it contains 39 .8 per cent of nickel, 21.85 per cent of copper, 2.16 per cent of iron and 4.26 per cent of sulphur. The mass is then treated with a stream of hydrogen at 240 C. under a pressure of 200 atmospheres and then treated with a stream of carbon monoxide at 220 C. under the same pressure. About 95.3 per cent of the nickel contained in the roasted product is converted into nickel carbonyl.

If the said nickel-copper matte be roasted until it contains 39.24 per cent of nickel, 21.6 per cent of copper, 2.15 per cent of iron and 7.8 per cent of sulphur and the roasted product be treated with hydrogen and carbon monoxide under the above mentioned conditions, only about 83.3 per cent of the nickel contained in the roasted product is converted into nickel carbonyl.

What we claim is:

1. A process of producing nickel carbonyl from nickel matte containing sulfur and at least one of the metals iron and copper which comprises roasting the matte until sulfur is removed to such an extent that the metal content of the roasted matte of at least one of the metals iron and copper is sufiicient to bind the remaining amount of sulfur, reducing the partially roasted product with hydrogen under substantial pressure and directly subjecting the roasted and reduced product to carbonylization by treatment with carbon monoxide.

2. A process of producing nickel carbonyl from nickel matte containing sulfur and at least one of the metals iron and copper which comprises roasting the matte until sulfur is removed to such an extent that the metal content of the roasted matte of at least one of the metals iron and copper is suflicient to bind the remaining amount of sulfur, reducing the partially roasted product at about 250 C. with hydrogen under substantial pressure and directly subjecting the roasted and reduced product to carbonylization by treatment with carbon monoxide.

LEO SCHLECHT. RUDOLF STAEGER. HERMANN KLIPPEL.