DE2146357A1 - Removing cobalt and nickel from iron oxide ores - - by rouling the ore with liquid reducer - Google Patents

Abstract

Ni and/or Co are removed from iron oxide contg. ores by mixing the milled ore with a liquid C-contg. reducer and passing the mixt. through two smooth or grooved rolls to consolidate. A consolidated strand-like form exits from the rolls and breaks up into flat high strength bodies which can be fed into the reducing furnace when Co and Ni metal, together with Fe3O4 are produced. The final stage is that of leaching where the Co and Ni contents are removed. Pref. 1-5% Bunker-C oil is used as reducer.

Description

Process for the reduction of oxidic iron-containing nickel and Cobalt ores The invention relates to a method for reducing oxidic iron-containing ores Nickel and / or cobalt ores, the ores after being finely ground with liquid carbon-containing reducing agents mixed and then in reducing units to metallic nickel and / or cobalt and largely to Fe3O4.

It is known to post oxidic iron-containing nickel and cobalt ores previous drying and fine grinding with a liquid carbonaceous neduktionsmi t tcl to mix and reduce the mixture, being nickel and Cobalt can be converted into the metallic form, while the iron largely too Fe3O4 is reduced.

During the subsequent leaching, nickel and cobalt are dissolved and separated from iron (US Pat. No. 3,100,700).

For an extensive reduction of the Ni and Co components of the oxidic Nickel ores to metal, the ores must be ground as finely as possible, whereby the natural weathering of the oxidic nickel ores causes the grinding favors that a large percentage of the ore ber @ i @ s in fine. @ in the form.

The consequence of this working method is that @@ @@@@@@@ in Grinded ores at the re @ uction in the R @@ ukti @@@@@@ rega @@ n, in front of all @ m in rotary furnaces, a show water-like flow behavior, d. H. the entire furnace shipment @tends to fire and at times flows through the furnace so quickly that the dwell time cannot be adequately regulated or kept constant.

It is also known that such fine-grained ores to a high Staubumlanf lead what special facilities for the dust separation and the Makes recirculation of the separated dust necessary.

A use of the dust-finely ground oxidic Mickel ores in shaft furnaces is not possible at all.

The invention is based on the problem of this uncontrollable To avoid the flow behavior and the formation of dust of the fine-grained ores.

According to the invention, this object is achieved by using liquid carbonaceous reducing agents mixed ore before use in the reduction units is compacted between two smooth or grooved rollers to form flakes.

The ore is compacted into a strand of material between the two rollers, the plate-like body of high strength, so-called as it emerges from the rollers Ln Scabs, disintegrates, which are almost free of pores or inner surfaces ("processing technology" No. 2, 1967, pages @@ 92; "Chemie-Anlagen-Verfahren" 1971, March issue, pages 57 - 61).

A preferred embodiment of the invention is that as liquid reducing agent 1 to 5% of the ore weight of Bunker-C-Oil mixed with the ore actually

The Bunker-C-Oil is used at the same time to compress the ore to form Schü @ pen as a binder. The binding properties @ n d @ s Bunker-C-Oil are improved as a result, that the oil @m preheated condition at @ 0 to 120 ° C at ni @ drig @ r @@@ k @ sität dem Ore is added, wodur @ h di Homog @@ i @@@ favored the mix When the scabs, which are pressed immediately after mixing, cool down, the Increasing viscosity of the Bunker-C oil then has a beneficial effect on the agglomerates' potency the end.

Another preferred embodiment of the invention consists in that the scabs are produced with a pressure of D to 8 t / cm roller width.

The gap between the rollers can be adjusted with the help of the hydraulic pressure the loose roller against the fixed roller can be varied within the limits of 3 to 6 mm.

The advantages achieved with the invention are in particular: that the finely ground ore has a more favorable flow behavior due to the compression to form scabs shows in the reduction aggregates, d. H. the residence time of the ore material within the reduction units can be precisely regulated and controlled. This runs the reduction more complete and the leaching output in that following the reduction The leaching process is 3 to 5% higher than the leaching output of the previous one Use of fine-grain ores.

The dust generation is certainly reduced and special facilities the return can be omitted.

Compacting the ore into scabs takes less effort connected as a theoretically possible pelletizing of the ore and that for the subsequent Leaching required comminution is easier than with compacted scabs with reduced and burned pellets.

The theoretically possible use of briquetted ores compared to the process according to the invention had the disadvantage that the briquetting costs would be much higher and the reducibility of the briquettes as a result of the substantially lesser Pore volume and the smaller specific surface of the briquettes are considerable would be worse.

An embodiment of the invention is described in more detail below and is explained with reference to the drawing.

A mixture of lateritic and serpentinite nickel ores was ground to the following grain size after drying:> 0.5 mm 0.5% 0.5 - 0.3 mm 3.2% 0.3 - 0.2 mm 5.8 o / 0.2 - 0.09 mm 16.7% 0.09 - 0.063 mm 6.1% 0.063 - 0.040 mm 9.4% (0.040 mm 58.3%.

After mixing the cold ore with 2.5 wt.% Bunker-C oil, the previously Was heated to 1000 C, the mixture was placed in a bunker 1 and out of this discharged with the aid of a plug screw 2 into the feed nip of a 2-roll press. The rollers 3 had a diameter of 500 mm and a width of 45 mm. Both Rollers 3 were equipped with smooth bandages. The pressing pressure was by means of hydraulics set to 5 t per cm of roll width.

In the nip, the mixture was compacted into a strand which after leaving the gap in irregularly shaped scabs 4 with a size of 1 to 10 mm and a thickness of 3 to 6 mm disintegrated. 15 6 of the amount of material sent did not occur in the form of scabs and were screened off and returned.

The scabs were a rotary kiln with a diameter of 0.5 m and 8 m in length. The reduction process and the amount of dust were very constant was only 5% of the task, while the reduction when using fine-grained ores in the Oven due to uncontrollable flow of the O charge to the discharge and through a high dust accumulation, which accounted for 20% of the task, was severely impaired. Partially there is no reduction at all, as the ore passes through uncontrollably and too quickly the stove wandered.

The reduced scabs were then placed in a ball or S-tab mill crushed to 4 1 mm to the fineness of the material required for leaching restore. The leaching was done with ammoniacal ammonium carbonate solution made according to the Nicaro process.

PaUer t

Claims (2)

P a t e n t a n s p r ü c h e 1. Process for the reduction of oxidic ferrous nickel and / or cobalt ores, the ores after being ground mixed with liquid reducing agents containing carbon and then in reduction units reduced to metallic nickel and / or cobalt and largely to Fe3O4, characterized in that that with liquid carbonaceous reducing agents mixed ore before use iii the reduction units between two smooth or corrugated rollers is compacted into scabs. 2. The method according to claim 1, characterized in that as a liquid Reducing agent 1 to 5% of the ore weight of Bunker-C-Oil is added to the ore. 3, method according to claims 1 and 2, characterized in that - @@ huet that the scabs are produced with a pressure of @ to @ / @ m roller width.