Method for preparing high-grade matte nickel by efficiently smelting laterite-nickel ore

Abstract

The invention relates to the technical field of metallurgical engineering, in particular to a method for preparing high-grade matte nickel through efficient smelting of laterite-nickel ore. The method comprises the following steps: (1) adding a product obtained by smelting laterite-nickel ore by adopting an RKEF process as a raw material into an alkaline pretreatment converter to form furnace liquid; (2) a top lance and a bottom lance of the alkaline pretreatment converter are matched for oxygen supply blowing to obtain high-nickel molten iron; (3) adding the high-nickel molten iron into an acidic AOD furnace for vulcanization, and carrying out combined blowing to obtain high-nickel matte; the combined blowing in the step (3) comprises blowing by utilizing a top lance and a side lance of the acidic AOD furnace in cooperation with oxygen and nitrogen-oxygen mixed gas. By adopting the method disclosed by the invention, process parameters and reaction conditions of each stage can be more accurately controlled, the content of smelting components can be more effectively adjusted to meet the component range of the high-grade matte nickel, the iron content is further reduced, the purity and yield of the high-grade matte nickel are improved, and efficient preparation of the high-grade matte nickel is realized.

Description

Technical Field

[0001] The present invention relates to the field of metallurgical engineering technology, and in particular to a method for efficiently smelting laterite nickel ore to prepare high-grade nickel matte. Background Art

[0002] Since electrolytic nickel is mainly obtained by smelting nickel sulfide ore, and the sulfide ore extraction process is mature, long-term large-scale mining has resulted in limited sulfide ore resources available for development in the world in the near future. In addition, the exploration and construction cycles of sulfide ore resources are relatively long, and development and utilization are relatively difficult. In contrast to the situation of nickel sulfide ore, laterite nickel ore resources are abundant. The amount of nickel metal stored in laterite ore accounts for 65% of the nickel reserves, while the nickel extracted from laterite nickel ore each year only accounts for 30% of the world's nickel production. Therefore, with the gradual reduction of nickel sulfide ore resources in the world, extracting nickel metal from laterite nickel ore will have great development prospects.

[0003] As an intermediate product in the nickel metal industry chain, high-grade nickel matte has great strategic significance. For example, the rapid development of my country's electric vehicle market has driven the continuous increase in the demand for power batteries. High nickelization, as the main technical route to improve the energy density of power batteries, is an inevitable development trend of the industry in the future. Statistical data show that by 2025, the proportion of high-nickel products in global and Chinese ternary positive electrode materials is expected to reach more than 50%. As an important raw material for the production of high-nickel ternary materials, the high-grade nickel matte industry has good development prospects. However, there are various problems in the existing high-grade nickel matte preparation process. For example, the pyrometallurgical smelting of laterite nickel ore often adopts the method of preparing low-grade nickel matte first by electric furnace smelting or oxygen-enriched side blowing smelting and then preparing high-grade nickel matte. The vulcanizing agent is added too early in this process, which makes the sulfur recovery rate too low. The smelting time of the traditional horizontal converter blowing method is relatively long, which seriously affects the production efficiency. Therefore, it is particularly important to develop a process for efficiently smelting laterite nickel ore to prepare high-grade nickel matte. Summary of the invention

[0004] In order to solve the above-mentioned deficiencies in the prior art, the present invention provides a method for efficiently smelting laterite nickel ore to prepare high-grade nickel matte.

[0005] In order to solve the above technical problems, one of the technical solutions provided by the present invention is as follows:

[0006] A method for efficiently smelting laterite nickel ore to prepare high-grade nickel matte comprises the following steps:

[0007] (1) adding the product obtained by smelting laterite nickel ore using the RKEF process as a raw material into an alkaline pretreatment converter to form a furnace liquid;

[0008] (2) using the top gun and bottom gun of the alkaline pretreatment converter to cooperate with oxygen supply and blowing to obtain high-nickel molten iron;

[0009] (3) adding the high-nickel molten iron into an acidic AOD furnace for sulfidation and composite blowing to obtain high-nickel matte; the composite blowing in step (3) comprises using the top gun and side gun of the acidic AOD furnace to respectively cooperate with oxygen and nitrogen-oxygen mixed gas for blowing.

[0010] In one embodiment, before the blowing in step (2), a slag-forming agent is added to the alkaline pretreatment converter, wherein the slag-forming agent is a slag-forming agent containing CaO and SiO 2 Preferably, the CaO-containing material is selected from lime, SiO 2 The material is selected from quartz stone; preferably, the CaO / SiO 2 The weight ratio is between 2.0 and 4.0.

[0011] In one embodiment, in step (2), the blowing includes a first blowing stage in which the iron content in the furnace liquid is more than 40wt% and a second blowing stage in which the iron content in the furnace liquid is less than 40wt%;

[0012] The maximum flow rate of oxygen blown into the top gun in the first blowing stage is 200Nm 3 / min, minimum flow rate is 120Nm 3 / min, oxygen supply pressure is 0.8-1.2MPa, and the maximum flow rate of oxygen blown into the bottom gun in the first blowing stage is 40Nm 3 / min, minimum flow rate is 20Nm 3 / min, oxygen supply pressure is 1.0MPa;

[0013] The flow rate of oxygen blown into the top gun in the second blowing stage is 80-100 Nm 3 / min, the oxygen supply pressure is consistent with the first blowing stage, the gas flow rate blown into the bottom gun is 0.1-0.2 times the oxygen flow rate blown into the top gun; the oxygen flow rate blown into the side gun in the second blowing stage is 30-80Nm 3 / min, and the oxygen supply pressure is consistent with that in the first blowing stage.

[0014] In one embodiment, the high-nickel molten iron has an iron content of 15wt% to 25wt% and a carbon content of 0.3wt% to 0.5wt%.

[0015] In one embodiment, in step (2), the blowing temperature is controlled at 1550°C to 1660°C.

[0016] In one embodiment, during the blowing process of step (2), if the temperature is higher than the control range of the blowing temperature, high nickel iron coolant is added into the furnace, and the maximum amount of the high nickel iron coolant added does not exceed 30% of the weight of the furnace liquid.

[0017] In one embodiment, before the sulfurization in step (3), quartz is added to the acidic AOD furnace, and the amount of quartz added is 15% to 20% of the weight of the high-nickel molten iron.

[0018] In one embodiment, the vulcanizing agent used for vulcanization is selected from sulfur and / or ferrous sulfide.

[0019] In one embodiment, in step (3), the temperature in the acidic AOD furnace is controlled at 1210°C to 1410°C.

[0020] In one embodiment, in step (3), the flow rate of oxygen blown into the top gun is 80-100 Nm 3 / min, the flow rate of nitrogen and oxygen mixed gas blown in by the side gun is 50~80Nm 3 / min, wherein the flow ratio of nitrogen to oxygen in the nitrogen-oxygen mixed gas is 2:1.

[0021] Based on the above, compared with the prior art, the method for efficiently smelting laterite nickel ore to prepare high-grade nickel matte provided by the present invention has the following beneficial effects:

[0022] (1) The present invention adopts a multi-stage smelting process of RKEF, alkaline pretreatment converter, and acidic AOD furnace smelting in sequence to prepare high-grade nickel matte from laterite nickel ore, wherein the RKEF stage adopts a mineral thermal electric furnace for reduction smelting, the pretreatment alkaline converter stage adopts alkaline materials and top and bottom composite blowing and refining, and the acidic AOD furnace smelting stage adopts an acidic solvent and top and side composite blowing process; thus, the method of the present invention can more accurately control the process parameters and reaction conditions of each stage, more effectively adjust the smelting component content to meet the high-grade nickel matte component range, and further reduce the iron content, thereby improving the purity and output of the high-grade nickel matte, and realizing the efficient preparation of the high-grade nickel matte.

[0023] (2) The present invention adopts the method of obtaining high-nickel molten iron by an alkaline converter. Since the furnace is in an alkaline atmosphere, no vulcanizing agent is added in the process, and the obtained high-nickel molten iron is directly poured into an acidic AOD furnace in liquid form, and then a vulcanizing agent is added in the process for treatment. The intermediate process does not involve water quenching, so the required heat is greatly reduced. At the same time, since the vulcanization process in AOD is an acidic atmosphere, the yield of sulfur can be greatly improved.

[0024] Other features and beneficial effects of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other beneficial effects of the present invention can be realized and obtained by the structures particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 A process flow chart for efficiently smelting laterite nickel ore to prepare high-grade nickel matte is provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0027] In the description of the present invention, it should be noted that all terms used in the present invention (including technical terms and scientific terms) have the same meanings as those generally understood by ordinary technicians in the field to which the present invention belongs, and cannot be understood as limiting the present invention; it should be further understood that the terms used in the present invention should be understood to have the same meanings as these terms in the context of this specification and in the relevant fields, and should not be understood in an idealized or overly formal sense, unless explicitly defined in the present invention.

[0028] Please refer to Figure 1 As shown, an embodiment of the present invention provides a method for efficiently smelting laterite nickel ore to prepare high-grade nickel matte, comprising the following steps:

[0029] (1) adding the product obtained by smelting laterite nickel ore using the RKEF process as a raw material into an alkaline pretreatment converter to form a furnace liquid;

[0030] Specifically, the RKEF process is used to prepare the nickel iron water raw material required for high-grade nickel matte, and the roasted sand required for the submerged arc furnace is fed into the submerged arc furnace through the feeding pipe from the roasting rotary kiln; the submerged arc furnace adopts a high voltage and low current mode, and the roasted sand discharged from the rotary kiln is evenly distributed into the submerged arc furnace under a heat-insulated state. The roasted sand is heated by the arc resistance, and the residual carbon in the roasted sand reduces the oxides of nickel and iron. The chemical reactions involved include:

[0031] (2NiO·SiO 2 )+C=2Ni+2CO+SiO 2

[0032] (2FeO·SiO 2 )+2C=2Fe+2CO+SiO 2

[0033] The iron and nickel produced are infinitely soluble in each other in liquid state, producing an iron-nickel metal mixture. Due to the density difference, the slag and iron are separated, the nickel-iron metal liquid is located at the bottom, and the residual oxide slag floats on the top, and finally nickel-iron water containing about 10% nickel is produced.

[0034] The slag outlet and iron outlet are provided on the ore-fired furnace. The iron outlet and slag outlet will discharge molten iron and slag regularly. The slag is discharged every 2 hours, and each slag discharge takes about 40 minutes. The molten iron will directly enter the converter through the chute. The molten iron is discharged about once every 4 to 5 hours, and each iron discharge takes about 15 to 30 minutes. The temperature of the produced nickel iron water is between 1300 and 1450°C.

[0035] (2) using the top gun and bottom gun of the alkaline pretreatment converter to cooperate with oxygen supply and blowing to obtain high-nickel molten iron;

[0036] Specifically, the nickel iron water produced by the RKEF process is added to the alkaline pretreatment converter through the molten iron ladle to form a furnace liquid, and the alkaline pretreatment converter is an alkaline atmosphere; in a preferred embodiment, before the blowing of step (2), a slag-forming agent is added to the alkaline pretreatment converter, and the slag-forming agent is a slag-forming agent containing CaO and SiO 2 Preferably, the CaO-containing material is selected from lime, SiO 2 The material is selected from quartz stone; preferably, the CaO / SiO 2 The weight ratio is between 2.0 and 4.0.

[0037] In the embodiment of the present invention, the lining of the alkaline pretreatment converter is alkaline material, the working layer is made of magnesia carbon bricks, and the permanent layer is made of magnesia bricks. Top and bottom composite blowing is adopted, the top blowing oxygen working pressure is 0.8-1.2MPa, and the maximum oxygen flow rate is 200Nm 3 / min; the oxygen pressure in the bottom blowing system is 1.0MPa, and the maximum oxygen flow rate is 40Nm 3 / min. Since 80% of the furnace liquid in the alkaline pretreatment converter will be oxidized into slag, the amount of nickel iron water charged at the beginning of blowing is 65% to 70% of the average molten iron output of the alkaline pretreatment converter, providing sufficient reaction space for deironing and decarburization. When oxygen is blown into the molten nickel iron water in the furnace, since Ni's affinity for oxygen is not as great as Fe and C, and Fe accounts for the majority of the melt, Fe is first oxidized into the slag layer, and C is discharged in the form of CO. After the iron content and carbon content in the nickel iron water reach the requirements (the iron content is blown to 15% to 25%, and the carbon content is blown to 0.3% to 0.5%), high-nickel iron water is produced.

[0038] In order to adapt to the serious problem of nickel oxidation caused by low iron content and high nickel content in the late stage of oxidation, when the iron content in nickel-iron water is lower than 40%, it is necessary to reduce the oxygen injection flow rate. The oxygen flow rate adjustment range is 1~3Nm 3 / (t·min). It should be noted that when the iron content in nickel-iron water is lower than 40%, it means that the iron content in the furnace liquid has dropped by more than half. If the original flow rate is maintained, the nickel in the furnace liquid will be oxidized in large quantities.

[0039] In this embodiment, during blowing, the temperature is controlled at 1550°C to 1660°C. If the temperature is too high, high-nickel iron coolant is added to the furnace to cool it down. The maximum amount of coolant added does not exceed 30% of the weight of the nickel iron water in the furnace.

[0040] Due to the excellent metallurgical dynamics conditions of the alkaline pretreatment converter, the entire oxygen blowing process to remove iron and other easily oxidizable elements lasts about 100 to 150 minutes.

[0041] (3) adding the high-nickel molten iron into an acidic AOD furnace for sulfidation and composite blowing to obtain high-nickel matte; the composite blowing in step (3) comprises using the top gun and side gun of the acidic AOD furnace to respectively cooperate with oxygen and nitrogen-oxygen mixed gas for blowing.

[0042] Specifically, the high-nickel iron water obtained from the alkaline pretreatment converter is added to the acidic AOD furnace. Acidic clay bricks are used as refractory materials in the furnace, and quartz stone is used as a solvent to create an acidic atmosphere. The amount of quartz stone added is 15% to 20% of the total amount of high-nickel iron water. According to the batching calculation, a vulcanizing agent is added to the furnace for vulcanization at one time. The vulcanizing agent can be sulfur or ferrous sulfur as needed. During the entire vulcanization stage, the temperature in the furnace is maintained at 1210 to 1410°C. When the temperature is too high, an appropriate amount of quartz stone can be added to cool it down.

[0043] The acidic AOD blowing process uses the top-side combined blowing process to further reduce the iron content in the high-nickel iron water. The top oxygen gun flow rate is 80-100Nm 3 / min, the flow ratio of oxygen and nitrogen in the side gun is 2:1, and the total flow rate of the side gun gas is 50~80Nm 3 / min, where the role of nitrogen is to improve the reaction kinetics of the molten pool and it does not participate in the actual reaction. When the iron content in the acidic AOD furnace is 4% to 5% and the sulfur content is 20% to 25%, the blowing is stopped and the whole sulfurization time is about 250 to 350 minutes. As needed, the obtained high-iron matte furnace liquid can be obtained by water quenching to obtain granular high-iron matte, or high-iron matte ingots can be obtained by die casting.

[0044] The first blowing stage of the embodiment of the present invention adopts a combination of top blowing and bottom blowing, which has the advantage that the top blowing can quickly reduce iron in the early stage, and the bottom blowing assists in stirring. The bottom blowing is carried out through refractory bricks, so the flow rate is relatively small; while the second blowing stage adopts a combination of top blowing and side blowing, which has the advantage that the side blowing is directly blown through a pipeline, which can increase the flow rate and control the gas ratio to achieve the effect of reducing iron and increasing nickel. At this time, the top blowing is performed as an auxiliary function.

[0045] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments; the technical features designed in different implementation modes of the present invention described below can be combined with each other as long as they do not conflict with each other; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0046] Example

[0047] The laterite nickel ore with the composition described in Table 1 was roasted and reduced by RKEF process. The 48MVA submerged arc furnace produced molten nickel iron once every 5 hours. The output through the tapping port of the submerged arc furnace was 55t each time. The composition was as described in Table 2. The temperature of the molten nickel iron was 1410°C. The RKEF slag was discharged through the tapping port. The composition was as shown in Table 3.

[0048] Table 1 Composition of laterite nickel ore

[0049]

[0050] Table 2 RKEF nickel-iron water composition

[0051]

[0052] Table 3 RKEF slag composition

[0053]

[0054] RKEF nickel iron water is added to the pretreatment converter through the iron ladle. The pretreatment converter capacity is 80t. 8.5t of quartz stone and 37t of lime are added into the furnace. The slag basicity is 3.0. The top blowing oxygen pressure is 1.0MPa and the flow rate is 35Nm 3 / min, at this time, a violent oxidation reaction occurs in the furnace, and the iron and other easily oxidizable elements in the nickel-iron water are oxidized in large quantities.

[0055] After 25 minutes, the temperature of the nickel-iron water in the pretreatment converter was measured. At this time, the temperature was 1680℃ and the iron content in the nickel-iron water was 68%. At this time, 17t of high-nickel-iron coolant with a nickel content of 30% was added to the furnace to cool it down to 1580℃ and continue blowing. After smelting for 45 minutes, the temperature was continued to be measured. The temperature in the furnace was 1630℃. Samples were taken for component analysis. After component analysis, the iron content in the nickel-iron water was 38%. At this time, the oxygen flow rates of the top gun and the bottom gun were adjusted to 100Nm 3 / min and 15Nm 3 / min. Continue blowing for 120min, take a sample and measure the temperature. At this time, the temperature is 1650℃ and the iron content is 20.7%. Stop blowing and the weight of the obtained high-nickel molten iron is 14.5t. The specific composition of the high-nickel molten iron produced by the pretreatment converter is shown in Table 4.

[0056] Table 4 Composition of high nickel molten iron produced by pretreatment converter

[0057]

[0058] The high-nickel iron water obtained from the pretreatment converter is added to the acidic AOD furnace. The capacity of the acidic AOD furnace is 30t. 2.5t of quartz stone is added. At this time, the temperature in the furnace is 1230℃. 7.4t of ferrous sulfide is added. The composition of the added ferrous sulfide is shown in Table 5.

[0059] Table 5 Sulfur iron composition table

[0060]

[0061] Open the acid AOD furnace top gun and side gun, the top gun flow rate is 80Nm 3 / min, the total flow rate of the side gun is 60Nm 3 / min, the flow ratio of oxygen and nitrogen is 2:1. After 200 minutes of blowing, sampling and temperature measurement, at this time the iron content in the furnace liquid is 12%, the temperature is 1480 ℃, at this time, 0.8t of quartz stone is added to cool the furnace liquid to 1270 ℃. Continue blowing, when the total blowing time is 300min, sampling and temperature measurement again, at this time the furnace liquid temperature is 1400 ℃, the chemical composition analysis is 4.3% Fe, 75% Ni, 20.5% S, 0.3% C. This composition is in line with the composition range of high nickel matte, stop blowing oxygen, and water quench the high nickel matte furnace liquid to obtain 14.2t of granular high nickel matte product.

[0062] In addition, those skilled in the art should understand that, although there are many problems in the prior art, each embodiment or technical solution of the present invention can be improved in only one or several aspects, without having to solve all the technical problems listed in the prior art or background technology at the same time. Those skilled in the art should understand that the content not mentioned in a claim should not be used as a limitation on the claim.

[0063] Although the terms such as RKEF process, alkaline pretreatment converter, top gun, bottom gun, side gun, acidic AOD furnace, blowing, nitrogen-oxygen mixed gas, slagging agent, sulfiding agent, etc. are used more frequently in this article, the possibility of using other terms is not excluded. The use of these terms is only to more conveniently describe and explain the essence of the present invention; interpreting them as any additional restrictions is contrary to the spirit of the present invention; the terms "first", "second", etc. (if any) in the description and claims of the embodiments of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for efficiently smelting laterite nickel ore to prepare high-grade nickel matte, characterized in that: The following steps are involved: (1) adding the product obtained by smelting laterite nickel ore using the RKEF process as a raw material into an alkaline pretreatment converter to form a furnace liquid; (2) using the top gun and bottom gun of the alkaline pretreatment converter to cooperate with oxygen supply and blowing to obtain high-nickel molten iron; (3) adding the high-nickel molten iron into an acidic AOD furnace for sulfidation and composite blowing to obtain high-nickel matte; the composite blowing in step (3) comprises using the top gun and side gun of the acidic AOD furnace to respectively cooperate with oxygen and nitrogen-oxygen mixed gas for blowing.

2. The method according to claim 1, characterized in that Before carrying out the blowing in step (2), a slag-forming agent is added to the alkaline pretreatment converter, wherein the slag-forming agent is a material containing CaO and SiO2; preferably, the CaO-containing material is selected from lime, and the SiO2-containing material is selected from quartz and / or dolomite; preferably, the weight ratio of CaO / SiO2 in the slag-forming agent is between 2.0 and 4.

0.

3. The method according to claim 1, characterized in that In step (2), the blowing includes a first blowing stage in which the iron content in the furnace liquid is above 40 wt % and a second blowing stage in which the iron content in the furnace liquid is less than 40 wt %; The maximum flow rate of oxygen blown into the top gun in the first blowing stage is 200Nm 3 / min, minimum flow rate is 120Nm 3 / min, oxygen supply pressure is 0.8-1.2MPa, and the maximum flow rate of oxygen blown into the bottom gun in the first blowing stage is 40Nm 3 / min, minimum flow rate is 20Nm 3 / min, oxygen supply pressure is 1.0MPa; The flow rate of oxygen blown into the top gun in the second blowing stage is 80-100 Nm 3 / min, the oxygen supply pressure is consistent with that in the first blowing stage, and the gas flow rate blown into the bottom gun is 0.1 to 0.2 times the oxygen flow rate blown into the top gun; The flow rate of oxygen blown into the side gun in the second blowing stage is 30-80 Nm 3 / min, and the oxygen supply pressure is consistent with that in the first blowing stage.

4. The method according to claim 1, characterized in that: The high-nickel molten iron has an iron content of 15wt% to 25wt% and a carbon content of 0.3wt% to 0.5wt%.

5. The method according to claim 1, characterized in that In step (2), the blowing temperature is controlled at 1550°C to 1660°C.

6. The method according to claim 5, characterized in that During the blowing process of step (2), if the temperature is higher than the control range of the blowing temperature, high nickel iron coolant is added into the furnace, and the maximum amount of the high nickel iron coolant added does not exceed 30% of the weight of the furnace liquid.

7. The method according to claim 1, characterized in that Before the sulfurization in step (3), quartz is added into the acidic AOD furnace, wherein the amount of quartz added is 15% to 20% of the weight of the high-nickel molten iron.

8. The method according to claim 1, characterized in that The vulcanizing agent used for vulcanization is selected from sulfur and / or ferrous sulfide.

9. The method according to claim 1, characterized in that: In step (3), the temperature in the acidic AOD furnace is controlled at 1210°C to 1410°C.

10. The method according to claim 1, characterized in that In step (3), the flow rate of oxygen blown into the top gun is 80-100 Nm 3 / min, the flow rate of nitrogen and oxygen mixed gas blown in by the side gun is 50~80Nm 3 / min, wherein the flow ratio of nitrogen to oxygen in the nitrogen-oxygen mixed gas is 2:1.

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