Preparation process of nickel-iron alloy

文档序号:776080 发布日期:2021-04-09 浏览:31次 中文

阅读说明:本技术 一种镍铁合金的制备工艺 (Preparation process of nickel-iron alloy ) 是由 刘日宏 段景文 于 2020-11-30 设计创作,主要内容包括:本发明公开了一种镍铁合金的制备工艺,包括如下步骤:S1、将原矿石进行烘干,使原矿石水分含量在5~10%;S2、添加占原矿石质量3~8%的还原剂到原矿石中,将其混合均匀并送至回转窑内烧结后出炉,获得烧结物;S3、将烧结物进行加热熔炼,得到镍铁合金。本发明经过研究发现,在回转窑内烧结时的温度在1000~1200℃并在700~900℃出料高温预还原烧结物,能够降低镍和铁烧损量减少,并去除离子水,进而增加后续熔炼后产出的镍铁合金的产量,杜绝了因离子水引起的喷炉安全风险,并现有的镍铁合金常规生产法为烧结后冷料入炉,熔炼时间过久,而本申请在较高的温度(700~900℃)即出炉,可以减少熔炼处理的时间,进而使得镍铁合金的产出更快,最终实现产量增高的效果。(The invention discloses a preparation process of a nickel-iron alloy, which comprises the following steps: s1, drying the raw ore to enable the moisture content of the raw ore to be 5-10%; s2, adding a reducing agent which accounts for 3-8% of the mass of the raw ore into the raw ore, uniformly mixing the raw ore and the reducing agent, conveying the mixture into a rotary kiln for sintering, and discharging the mixture out of the kiln to obtain a sinter; and S3, heating and smelting the sinter to obtain the nickel-iron alloy. According to research, the invention discovers that the sintering temperature is 1000-1200 ℃ during sintering in the rotary kiln, the high-temperature pre-reduction sinter is discharged at 700-900 ℃, the burning loss of nickel and iron can be reduced, ionized water is removed, the output of the nickel-iron alloy produced after subsequent smelting is increased, the safety risk of furnace spraying caused by the ionized water is avoided, the conventional production method of the nickel-iron alloy is that cold materials after sintering are fed into the furnace, the smelting time is too long, the nickel-iron alloy is discharged at a higher temperature (700-900 ℃), the smelting time can be reduced, the output of the nickel-iron alloy is faster, and the effect of increasing the output is finally realized.)

1. A preparation process of a nickel-iron alloy is characterized by comprising the following steps:

step S1, drying the raw ore to enable the moisture content of the raw ore to be 5-10%;

step S2, adding a reducing agent which accounts for 3-8% of the mass of the raw ore into the raw ore, uniformly mixing the raw ore and the reducing agent, conveying the mixture into a rotary kiln for sintering, and taking the sintered product out of the kiln after sintering to obtain a high-temperature pre-reduction sintered product;

step S3, sending the high-temperature pre-reduced sinter obtained after the sintering out of the kiln into a submerged arc furnace for heating and smelting to obtain a nickel-iron alloy;

wherein the mass ratio of silicon dioxide to calcium oxide in the raw ore is 6-7: 10.

2. The process for preparing a ferronickel alloy according to claim 1, wherein the raw ore of step S1 is laterite-nickel ore, the raw ore has a silicon dioxide content of 40-50% by mass and a calcium oxide content of 3-5% by mass.

3. The process for preparing a ferronickel alloy according to claim 1, wherein the raw ore of step S1 is laterite-nickel ore, the raw ore has a silicon dioxide content of more than 50% by mass and a calcium oxide content of 3-5% by mass, and limestone is further added to the raw ore.

4. The process of claim 1, wherein the reductant in step S2 is coke, and the coke has a particle size of 3-5 mm.

5. The process for preparing a ferronickel alloy according to claim 1, wherein the sintering temperature in the step S2 is 1000 to 1200 ℃, and the discharging temperature of the high-temperature pre-reduced sinter is 700 to 900 ℃; the rotating speed of the kiln is 3-4 r/min.

Technical Field

The invention relates to the technical field of metallurgy, in particular to a preparation process of a nickel-iron alloy.

Background

Nickel is an important strategic metal and is an excellent corrosion-resistant material, and nickel is not only a basic material for manufacturing nickel alloy, but also an alloy element in other alloys (such as iron, copper, aluminum and the like). Nickel is mainly used in the metallurgical industry and is an important alloy element for producing stainless steel, special steel, high-temperature alloy, precision alloy, heat-resistant alloy and the like. Nickel is also widely used in the fields of electroplating, magnetic materials, electronics, electric appliances, electromagnetic and sensor, oxygen storage alloy, shape memory alloy, national defense, aviation, aerospace, rocket technology and the like, for example, super nickel or nickel alloy is used as a high-temperature structural material, and nickel alloy are used in parts with special purposes, instrument manufacturing, machine manufacturing, rocket technical equipment, atomic reactor; nickel is also of particular value in the chemical industry for the production of alkaline storage batteries, porous filters, catalysts, pigments, dyes, etc.; large plants often use nickel clad steel, the nickel clad layer being hot rolled or welded; nickel is used for manufacturing production parts of corrosive chemical products. At present, the consumption of nickel is second to that of copper, aluminum, lead and zinc but is the fifth place in the non-ferrous metals all over the world, and the nickel is regarded as an important strategic substance for national economic construction, and the effective development and comprehensive utilization of the resources of the nickel are always paid attention to by various countries. Currently, 70% of the world's nickel is extracted from sulphide ores, while about 72% of the global nickel resource is present in oxidic ores. Along with the exploitation of nickel sulfide ores, the global resource of nickel sulfide ores is gradually reduced, and the economic and efficient utilization of nickel oxide ores (laterite-nickel ores) is more and more paid attention by people.

The prior direct production process of ferronickel mainly comprises the following steps: (1) smelting in an electric furnace to produce ferronickel: the energy consumption is high, and the production cost is overhigh; (2) smelting in a blast furnace to produce ferronickel: the adaptability to raw ores is poor, the requirement on magnesium content is strict, in addition, fine ores cannot be processed, and the strict requirement on furnace charging materials is also met; (3) the blast furnace smelting of ferronickel is characterized by large capacity, but huge investment, high production cost and serious damage to the blast furnace; (4) reduction roasting-ore dressing process for producing ferronickel: although the process has been successfully used for industrial production, the process technology is immature. The reduction roasting-mineral separation process for producing ferronickel is the most common ferronickel alloy production process at present, but the major problem of the ferronickel in the production process is that the burning loss of the ferronickel is large in the production process.

Disclosure of Invention

In order to overcome the problems in the prior art, the invention provides a preparation process of a nickel-iron alloy with less burning loss in the production process.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a preparation process of a nickel-iron alloy comprises the following steps:

step S1, drying the raw ore to enable the moisture content of the raw ore to be 5-10%;

step S2, adding a reducing agent which accounts for 3-8% of the mass of the raw ore into the raw ore, uniformly mixing the raw ore and the reducing agent, conveying the mixture into a rotary kiln for sintering, and taking the sintered product out of the kiln after sintering to obtain a high-temperature pre-reduction sintered product;

step S3, sending the high-temperature pre-reduced sinter obtained after the sintering out of the kiln into a submerged arc furnace for heating and smelting to obtain a nickel-iron alloy;

wherein the mass ratio of silicon dioxide to calcium oxide in the raw ore is 6-7: 10.

Further, the raw ore of the step S1 is laterite-nickel ore, the raw ore contains 40-50% by mass of silicon dioxide and 3-5% by mass of calcium oxide.

Further, the raw ore of the step S1 is laterite-nickel ore, the raw ore contains more than 50% by mass of silicon dioxide and 3-5% by mass of calcium oxide, and limestone is added into the raw ore.

Further, the reducing agent in the step S2 is coke, wherein the particle size of the coke is 3-5 mm.

Further, the sintering temperature in the step S2 is 1000-1200 ℃, and the discharging temperature of the high-temperature pre-reduced sinter is 700-900 ℃; the rotating speed of the kiln is 3-4 r/min.

Compared with the prior art, the invention has the following beneficial effects:

(1) according to the invention, researches show that the sintering temperature in the rotary kiln is 1000-1200 ℃ and the high-temperature pre-reduced sinter is obtained by discharging at 700-900 ℃, so that the burning loss of nickel and iron in the sinter produced by sintering can be reduced, the output of the nickel-iron alloy produced after subsequent smelting is increased, the conventional discharging temperature of the existing nickel-iron alloy is 400-500 ℃, the sintering time is too long, the high-temperature pre-reduced sinter in the application directly enters the furnace after being discharged from the furnace at a higher temperature (700-900 ℃), the smelting time is reduced, and the productivity of the nickel-iron alloy is improved.

(2) According to the invention, coke is mixed in raw ore, and is sintered and smelted, and the coke is used as a reducing agent at the sintering temperature (1000-1200 ℃) to reduce NiO and other oxides in the raw ore to obtain the ferronickel alloy, and the inventor finds that the particle size of the added coke is 3-5 mm, so that the coke particles are in contact with each other and fully react to generate reducing gas CO, and therefore the NiO and other oxides in the raw ore can be completely reduced, the ferronickel alloy with higher strength is ensured to be obtained, the ferronickel alloy with better performance is obtained, and the ferronickel alloy is simultaneously improved; and simultaneously, the coke particles are prevented from being bonded on the inner wall of the rotary kiln to reduce the sintering space of the raw ore, thereby further improving the productivity of the ferronickel alloy.

(3) According to the invention, when the mass percentage of the silicon dioxide is detected to be more than 50% and the mass percentage of the calcium oxide is detected to be 3-5%, the limestone is added into the raw ore, and carbon dioxide is released from the limestone during sintering to generate calcium oxide, so that the content of calcium can be increased, the mass ratio of the silicon dioxide to the calcium oxide in the raw ore can reach the required ratio, the raw ore is stable in performance in the subsequent treatment process, and the high-quality ferronickel alloy is produced.

Drawings

FIG. 1 is a flow chart of a smelting process of a ferronickel alloy in the invention.

Detailed Description

The present invention will be further described with reference to the following description and examples, which include but are not limited to the following examples.

The process for the preparation of the nickel-iron alloy in all the examples described below is shown in figure 1.

Example 1

A preparation process of a nickel-iron alloy comprises the following steps:

step S1, firstly, drying the laterite-nickel ore to enable the moisture content of the laterite-nickel ore to be 5-10%; and then, detecting the laterite-nickel ore, and determining that the mass ratio of silicon dioxide to calcium oxide is 6-7: 10, wherein the specific mass percentage of the silicon dioxide is 40-50%, and the mass percentage of the calcium oxide is 3-5%.

And S2, adding coke which accounts for 3-8% of the mass of the raw ore and has a particle size of 3mm into the raw ore, uniformly mixing the coke and the raw ore, conveying the mixture into a rotary kiln, sintering at the temperature of 1000 ℃ and the rotating speed of 3-4 r/min, and discharging the sintered product from the kiln at the temperature of 700 ℃ to obtain a high-temperature pre-reduction sintered product.

And step S3, feeding the obtained high-temperature pre-reduced sinter into a submerged arc furnace for heating and smelting to obtain the ferronickel alloy.

Example 2

A preparation process of a nickel-iron alloy comprises the following steps:

step S1, firstly, drying the laterite-nickel ore to enable the moisture content of the laterite-nickel ore to be 5-10%; and then, detecting the laterite-nickel ore, and determining that the mass ratio of silicon dioxide to calcium oxide is 6-7: 10, wherein the specific mass percentage of the silicon dioxide is 40-50%, and the mass percentage of the calcium oxide is 3-5%.

And step S2, adding coke which accounts for 3-8% of the mass of the raw ore and has a particle size of 4mm into the raw ore, uniformly mixing the coke and the raw ore, conveying the mixture into a rotary kiln, sintering at 1100 ℃ and a rotation speed of 3-4 r/min, and discharging the sintered product from the kiln at 800 ℃ to obtain a high-temperature pre-reduction sintered product.

And step S3, feeding the obtained high-temperature pre-reduced sinter into a submerged arc furnace for heating and smelting to obtain the ferronickel alloy.

Example 3

A preparation process of a nickel-iron alloy comprises the following steps:

step S1, firstly, drying the laterite-nickel ore to enable the moisture content of the laterite-nickel ore to be 5-10%; and then, detecting the laterite-nickel ore, and determining that the mass ratio of silicon dioxide to calcium oxide is 6-7: 10, wherein the specific mass percentage of the silicon dioxide is 40-50%, and the mass percentage of the calcium oxide is 3-5%.

And S2, adding coke which accounts for 3-8% of the mass of the raw ore and has a particle size of 4mm into the raw ore, uniformly mixing the coke and the raw ore, conveying the mixture into a rotary kiln, sintering at 1200 ℃ and 3-4 r/min, and discharging from the kiln at 850 ℃ to obtain a high-temperature pre-reduction sinter.

And step S3, feeding the obtained high-temperature pre-reduced sinter into a submerged arc furnace for heating and smelting to obtain the ferronickel alloy.

Example 4

A preparation process of a nickel-iron alloy comprises the following steps:

step S1, firstly, drying the laterite-nickel ore to enable the moisture content of the laterite-nickel ore to be 5-10%; and then, detecting the laterite-nickel ore, and determining that the mass ratio of silicon dioxide to calcium oxide is 6-7: 10, wherein the specific mass percentage of the silicon dioxide is 40-50%, and the mass percentage of the calcium oxide is 3-5%.

And S2, adding coke which accounts for 3-8% of the mass of the raw ore and has a particle size of 5mm into the raw ore, uniformly mixing the coke and the raw ore, conveying the mixture into a rotary kiln, sintering at 1200 ℃ and 3-4 r/min, and discharging from the kiln at 900 ℃ to obtain a high-temperature pre-reduction sinter.

And step S3, feeding the obtained high-temperature pre-reduced sinter into a submerged arc furnace for heating and smelting to obtain the ferronickel alloy.

Comparative example 1

A preparation process of a nickel-iron alloy comprises the following steps:

step S1, firstly, drying the laterite-nickel ore to enable the moisture content of the laterite-nickel ore to be 5-10%; and then, detecting the laterite-nickel ore, and determining that the mass ratio of silicon dioxide to calcium oxide is 6-7: 10, wherein the specific mass percentage of the silicon dioxide is 40-50%, and the mass percentage of the calcium oxide is 3-5%.

And S2, adding coke which accounts for 3-8% of the mass of the raw ore and has a particle size of 4mm into the raw ore, uniformly mixing the coke and the raw ore, conveying the mixture into a rotary kiln, sintering at 1100 ℃ and a rotating speed of 3-4 r/min, and discharging the sintered product from the kiln at 400 ℃ to obtain a high-temperature pre-reduction sintered product.

And step S3, feeding the obtained high-temperature pre-reduced sinter into a submerged arc furnace for heating and smelting to obtain the ferronickel alloy.

Comparative example 2

A preparation process of a nickel-iron alloy comprises the following steps:

step S1, firstly, drying the laterite-nickel ore to enable the moisture content of the laterite-nickel ore to be 5-10%; and then, detecting the laterite-nickel ore, and determining that the mass ratio of silicon dioxide to calcium oxide is 6-7: 10, wherein the specific mass percentage of the silicon dioxide is 40-50%, and the mass percentage of the calcium oxide is 3-5%.

And step S2, adding coke which accounts for 3-8% of the mass of the raw ore and has a particle size of 0.2mm into the raw ore, uniformly mixing the coke and the raw ore, conveying the mixture into a rotary kiln, sintering at 1100 ℃ and at a rotating speed of 3-4 r/min, and discharging the sintered product from the kiln at 800 ℃ to obtain a high-temperature pre-reduction sintered product.

And step S3, feeding the obtained high-temperature pre-reduced sinter into a submerged arc furnace for heating and smelting to obtain the ferronickel alloy.

Comparative example 3

A preparation process of a nickel-iron alloy comprises the following steps:

step S1, firstly, drying the laterite-nickel ore to enable the moisture content of the laterite-nickel ore to be 5-10%; and then, detecting the laterite-nickel ore, and determining that the mass ratio of silicon dioxide to calcium oxide is 6-7: 10, wherein the specific mass percentage of the silicon dioxide is 40-50%, and the mass percentage of the calcium oxide is 3-5%.

And step S2, adding coke which accounts for 3-8% of the mass of the raw ore and has a particle size of 10mm into the raw ore, uniformly mixing the coke and the raw ore, conveying the mixture into a rotary kiln, sintering at 1100 ℃ and at a rotating speed of 3-4 r/min, and discharging the sintered product from the kiln at 800 ℃ to obtain a high-temperature pre-reduction sintered product.

And step S3, feeding the obtained high-temperature pre-reduced sinter into a submerged arc furnace for heating and smelting to obtain the ferronickel alloy.

And (3) testing and analyzing:

the nickel-iron alloys prepared in examples 1 to 4 and comparative examples 1 to 2 were formed into nickel-iron alloy products, and the formed products were subjected to vickers hardness test, the results of which are shown in table 1.

Table 1: of the nickel-iron alloys prepared in examples 1-4 and comparative examples 1-2

Group of Hardness value
Example 1 630
Example 2 650
Example 3 670
Example 4 640
Comparative example 1 530
Comparative example 2 460
Comparative example 3 480

As can be seen from Table 1, the particle size of the coke and the discharge temperature of the obtained high-temperature pre-reduced sinter both have an influence on the properties of the obtained ferronickel alloy. When the particle size of the coke particles is small (less than 3mm), the coke particles are bonded on the inner wall of the rotary kiln along with the rotation of the rotary kiln, so that the coke particles cannot be fully contacted with air to generate CO, NiO and other oxides in the raw ore are completely reduced, and the nickel-iron alloy with higher strength cannot be obtained; and along with the aggregation of coke particles on the inner wall of the rotary kiln, the space for sintering raw ores in the rotary kiln is reduced, thereby reducing the yield of the nickel-iron alloy. Secondly, when the particle size of the coke particles is larger than 5mm, the coke particles can not be fully contacted with the air to generate enough reducing gas CO, so that NiO and other oxides in the raw ore are not beneficial to being completely reduced, and the yield of the nickel-iron alloy is reduced.

According to the invention, the particle size of the coke particles for reducing the raw ore, the sintering temperature of the raw ore in the rotary kiln and the discharge temperature of the high-temperature pre-reduced sinter obtained after sintering are adjusted, so that the coke particles can react with oxygen to generate reducing gas CO, NiO and other oxides in the ore are completely reduced, and the nickel-iron alloy with higher strength is ensured to be obtained; secondly, coke particles are prevented from being bonded on the inner wall of the rotary kiln, so that the sintering space of the rotary kiln for raw ores is reduced, and the yield of the nickel-iron alloy is improved; finally, the sintering time is shortened by improving the kiln discharging temperature of the sintered high-temperature pre-reduced sinter, the fusing time is shortened, and the yield of the nickel-iron alloy is further improved.

The above-mentioned embodiment is only one of the preferred embodiments of the present invention, and should not be used to limit the scope of the present invention, but all the insubstantial modifications or changes made within the spirit and scope of the main design of the present invention, which still solve the technical problems consistent with the present invention, should be included in the scope of the present invention.

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