JPH05295469A - Production of ferro-nickel - Google Patents

Abstract

PURPOSE:To improve recovery rate of nickel by charging nickel oxide ore into a rotary kiln together with a reducing agent, executing semi-smelting reduc tion, slowly cooling the obtd. clinker, then pulverizing the clinker and recoverying the ferro-nickel. CONSTITUTION:The iron contg. nickel oxide ore is charged into the rotary kiln together with reducing agent such as anthracite. Then, a semi-smelting reduction is executed to the nickel oxide ore while tumbling it in an oxidizing combustion gas flow at a high temp. of about 1300 deg.C. By this method, Ni oxide and Fe oxide contents in the ore are reduced to obtain the ferro-nickel. At this time, the clinker containing Fe and Ni formed in the rotary kiln is slowly cooled to about 810 deg.C by air-cooling and thereafter, if necessary, this clinker is further rapidly cooled by water-cooling, etc., and successively, this clinker is pulverized and the ferro-nickel particles are recovered by a magnetic separation and floatation. By this method, most of Ni contained in sulfide layer 2 in the clinker is recovered by the ferro-nickel particles 1 and the sulfide layer 2 is removed together with slag 3 from the ferro-nickel particles 1 by pulverizing the clinker.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing ferronickel, and particularly to a method for producing ferronickel from nickel oxide ore with a high recovery rate.

[0002]

2. Description of the Related Art Conventional methods for producing ferronickel from nickel oxide ore by a dry method include a continuous method using a rotary kiln, and a batch method using a sintering pot. , Respectively known. For example, in the former case, there is a method using a semi-smelting reduction furnace proposed by the present applicant, which is disclosed as Japanese Patent Publication No. 1-21855. In this method, a reducing material (anthracite) is charged together with nickel oxide ore into a rotary kiln, and rolling granulation is carried out in an oxidizing combustion air stream to carry out semi-melt reduction to remove Ni oxide and Fe oxide contents in the ore. This is a technique of reducing and then clinker, which is a mixture of ferronickel and slag, is water-cooled to be coarsely crushed, further crushed by a rod mill or the like, and subjected to flotation and magnetic separation to recover ferronickel.

[0003]

In the above-mentioned conventional technique using a rotary kiln, 1300 ° C. from the rotary kiln.
As shown in FIG. 1, the water-cooled clinker discharged from the reactor was mainly composed of slag 3 and ferronickel particles 1, and the surface of the ferronickel particles was the sulfide phase 2 of Fe and Ni.
It is usually covered with. Generally, although 24.76 wt% of Ni is also contained in the sulfide phase 2, it is separated from the ferronickel grain surface in the crushing step described above and becomes a slag component, which is not recovered as a so-called Ni component. This was one of the causes of the decrease in Ni recovery rate.

Therefore, an object of the present invention is to recover Ni in the sulfide phase 2 which was once discarded together with the slag, and to recover Ni.
The goal is to establish a technology that can further improve the recovery rate and overcome the problems of the conventional technology.

[0005]

[Means for Solving the Problems] The inventors of the present invention have conducted diligent researches on the handling of the sulfides which inhibit the improvement of the Ni recovery rate. To solve the problems, the operation of the rotary kiln was The present invention has been completed based on the finding that it is effective to devise a method for cooling the clinker generated in the furnace after smelting reduction.

That is, a reducing material (anthracite) is charged together with nickel oxide ore into a rotary kiln, and the nickel oxide and Fe oxide components in the ore are removed by performing semi-smelting reduction while rolling in a high-temperature oxidizing combustion air stream. When the clinker is reduced to be discharged from the rotary kiln, the discharged raw material is immediately dropped into water for rapid cooling and water granulation in the conventional technique. Then, it was rapidly cooled, and thereafter, ferronickel grains were collected by pulverization, flotation, and magnetic separation according to a conventional method, thereby obtaining ferronickel with a high Ni recovery rate.

[0007]

[Function] The clinker discharged from the rotary kiln (1300 ° C) was once air-cooled to 810 ° C, and then dropped into water for rapid cooling and crushing, and the macrostructure of the clinker was as shown in Fig. 1. It was found that the surface of the nickel particles was covered with the sulfide phase 2, and the particles thus formed were scattered in the slag. Certainly, in terms of macrostructure, the clinker rapidly cooled from 1300 ° C is very similar to the clinker cooled to 810 ° C and then water-cooled. However, when the sulfide phase of both samples was quantitatively analyzed by EPMA, as shown in Table 1, the sulfide phase of the rapidly cooled clinker contained 24.76 wt% of Ni, while 810
It was revealed that the sulphide phase of the clinker cooled by air after cooling to ℃ contained only 1.84 wt% Ni.

The inventors consider the cause of this as follows. That is, FeS, Ni in the sulfide phase
S is present and these sulfides are in contact with ferronickel, ie Fe and Ni. When the high temperature region is gradually cooled, in such a system, the reaction of the following formula (1) occurs preferentially, metal nickel is easily produced, and the reduction production of Ni is enhanced. Fe ＋ NiS → FeS ＋ Ni …… (1)

The slow cooling of the clinker for proceeding the reaction of the above formula (1) is effective up to 810 ° C. In addition, the cooling rate at this time may be a degree of cooling in the atmosphere.
In addition, the quenching treatment to be performed thereafter has the main purpose of roughly crushing the clinker by thermal shock and improving the pulverizability in the subsequent step by making the crystal grain size of the slag finer, and therefore, from a high temperature. It is more effective to quench it, but 810
Do not exceed ℃. The cooling rate during this rapid cooling may be about water cooling.

According to the research conducted by the present inventors, in consideration of the improvement of Ni recovery rate and the reduction of pulverizability, at least 1000-81
It was found that it is better to air cool the temperature range of 0 ° C. In order to prevent Ni oxidation loss during cooling and to enhance the effect, gradual cooling in a non-oxidizing atmosphere is preferable.

Further, the reason why the material is gradually cooled and then rapidly cooled is as follows.
This is because it is more effective to coarsely crush the clinker by thermal shock, and to make the slag grain size finer to improve the pulverizability in the subsequent step, and the second method of the present invention is exactly This phenomenon is used.

[0012]

EXAMPLES Examples according to the present invention and comparative examples are shown below. In each example, the experiment was performed with the raw material mixture ratio, rotary kiln operating conditions, crushing conditions, flotation conditions, and magnetic separation conditions kept constant. Example 1 140 kg of anthracite coal was added to 1 t of nickel oxide ore having the composition shown in Table 2, charged in a rotary kiln, tumbled and granulated in an oxidizing combustion air stream, and subjected to semi-melt reduction at a maximum temperature of 1400 ° C. did. Then 13 clinker from the rotary kiln
It was discharged at 00 ° C, air-cooled to 1000 ° C, and then water-cooled. After crushing the water-cooled clinker to a particle size of 0.2 mm or less, ferronickel particles were collected by flotation and magnetic separation. The Ni recovery rate at this time is shown in Table 3.

Example 2 140 kg of anthracite was added to 1 t of nickel oxide ore having the composition shown in Table 2, charged in a rotary kiln, and tumbled and granulated in an oxidizing combustion air stream at a maximum temperature of 1400 ° C. Semi-melt reduced. Then 13 clinker from the rotary kiln
It was discharged at 00 ° C, air-cooled to 810 ° C, and then water-cooled. After pulverizing the water-cooled raw material to a particle size of 0.2 mm or less, ferronickel particles were collected by flotation and magnetic separation. The Ni recovery rate at this time is shown in Table 3.

Example 3 140 kg of anthracite coal was added to 1 t of nickel oxide ore having the composition shown in Table 2, charged in a rotary kiln, and tumbled and granulated in an oxidizing combustion air stream at a maximum temperature of 1400 ° C. Semi-melt reduced. Then 13 clinker from the rotary kiln
It was discharged at 00 ° C, air-cooled to 810 ° C in a non-oxidizing atmosphere, and then water-cooled. After pulverizing the water-cooled raw material to a particle size of 0.2 mm or less, ferronickel particles were collected by flotation and magnetic separation. The Ni recovery rate at this time is shown in Table 3.

Example 4 To 1 t of nickel oxide ore having the composition shown in Table 2, 140 kg of anthracite was added and charged into a rotary kiln, and tumbled and granulated in an oxidizing combustion air stream at a maximum temperature of 1400 ° C. Semi-melt reduced. Then, the clinker was gradually cooled in a rotary kiln and discharged at 810 ° C. to be water-cooled. After crushing the water-cooled clinker to a particle size of 0.2 mm or less, ferronickel particles were collected by flotation and magnetic separation. The Ni recovery rate at this time is shown in Table 3.

Example 5 To 1 t of nickel oxide ore having the composition shown in Table 2, 140 kg of anthracite was added and charged into a rotary kiln. The granules were tumbled and granulated in an oxidizing combustion air stream at a maximum temperature of 1400 ° C. Semi-melt reduced. Then, the clinker discharged from the rotary kiln at 1300 ° C. was air-cooled to 25 ° C., pulverized to a particle size of 0.2 mm or less, and ferronickel particles were collected by flotation and magnetic separation. The Ni recovery rate at this time is shown in Table 3.

Comparative Example To 1 t of nickel oxide ore having the composition shown in Table 2, 140 kg of anthracite was added and charged into a rotary kiln, and the mixture was tumbled and granulated in an oxidizing combustion air stream at a maximum temperature of 1400 ° C. Melt reduced. Then 13 clinker from the rotary kiln
It was discharged at 00 ° C and immediately cooled with water. After crushing the water-cooled clinker to a particle size of 0.2 mm or less, ferronickel particles were collected by flotation and magnetic separation. The Ni recovery rate at this time is shown in Table 3.

[0018]

[Table 1]

[0019]

[Table 2]

[0020]

[Table 3]

As can be seen from the results shown in Table 3 above, the Ni recovery rate in Example 3 was 97.8%, and the Ni recovery rate in Comparative Example 9 was 9%.
The 6.4% Ni recovery was improved compared to 1.4%. In Example 1, since the cooling temperature was relatively high at 1000 ° C., the Ni recovery rate was
It remained at 94.5%. In Example 2, since Ni was cooled in the atmosphere, the Ni recovery rate was lower than that in Example 3, and was 96.3%. In Example 4, cooling was performed in the rotary kiln,
The Ni recovery rate equivalent to that in Example 3 was obtained. In Example 5, since the clinker was gradually cooled to room temperature, the crushability of the clinker was lowered, and the Ni recovery rate was 94.9%.

[0022]

As described above, according to the present invention,
Ferronikel with high Ni content can be easily produced from Ni oxide ore.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of an effluent clinker.

[Explanation of symbols]

 1 Ferronickel grain 2 Sulfide phase 3 Slag

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Nakajima 413 Sutsu, Miyazu, Kyoto Prefecture Nippon Metallurgical Industry Co., Ltd. Oeyama Factory

Claims (2)

[Claims] 1. A rotary kiln is charged with a reducing material together with nickel oxide ore, and is subjected to semi-molten reduction while rolling in a high-temperature oxidizing combustion airflow, thereby oxidizing N in the ore.
i, a method for producing ferronickel by reducing Fe oxide, characterized in that the Fe / Ni-containing clinker obtained after the semi-melt reduction is gradually cooled and then pulverized to recover ferronickel particles. Method for producing ferronickel. 2. A rotary kiln is charged with a reducing material together with nickel oxide ore, and is subjected to semi-molten reduction while rolling in a high-temperature oxidizing combustion air flow to obtain nickel oxide in the ore.
In the method of producing ferronickel by reducing Fe oxide, the Fe / Ni-containing clinker obtained after the semi-melt reduction is gradually cooled, then rapidly cooled, and then pulverized to recover ferronickel particles. A characteristic method for producing ferronickel.