Treatment method for high nickel matte leaching residue

Abstract

The present invention provides a method for treating high-nickel matte leaching slag, comprising: delivering high-nickel matte leaching slag, a carbonaceous reducing agent, a quartz stone slagging agent, and low-nickel sulfur to a reduction furnace in preset proportions; delivering natural gas and oxygen-enriched air to the reduction furnace in preset proportions to chemically react with the high-nickel matte leaching slag, carbonaceous reducing agent, quartz stone slagging agent, and low-nickel sulfur in the reduction furnace to produce secondary medium-nickel matte, secondary blowing slag, and flue gas; extracting the secondary medium-nickel matte using a wet process system to obtain metallic nickel, cobalt, gold, silver, target, and platinum; and deslagging the secondary blowing slag and flue gas using a pyrometallurgical smelting system and an acid production system, respectively. The present invention can address the current problems of high energy consumption, metal dispersion, and low recovery in the treatment of high-nickel matte leaching slag.

Description

Technical Field

[0001] The present invention relates to the field of smelting technology, and more particularly to a method for treating high-nickel matte leaching slag. Background Art

[0002] Currently, the following methods are used to treat waste high-nickel matte leaching residues generated by both hydrometallurgical and pyrometallurgical processes in the smelting industry. In the hydrometallurgical process, the high-nickel matte leaching residue is melted and separated at high temperatures. Fe2O3, Ni3S2, and Cu2S melt, and the oxide and matte phases, which are immiscible, separate into separate layers. This method, however, uses high-temperature electric furnaces to process the waste high-nickel matte leaching residue, as the melting point of Fe2O3 is 1565°C. This consumes a significant amount of electricity and results in high energy consumption. In pyrometallurgical processes, the high-nickel matte leaching residue is generally returned to the smelting process for treatment. Nickel, copper, and cobalt exist in the high-valent sulfide form of the high-nickel matte leaching residue, while iron exists as a trivalent oxide. After returning to the smelting process, the trivalent iron oxides are reduced to divalent oxides by the matte phase in the coal and concentrate added to the smelting process. This iron oxide then reacts with the added quartz to form a fayalite slag phase. After decomposition, high-valent sulfides of nickel, copper, and cobalt become low-valent sulfides, which then intermelt with low-valent sulfides in the concentrate to form low-nickel matte. While this method of treating high-nickel matte leaching residue, when treated together with the concentrate, solves the problem of hazardous waste disposal, the precious metals and nickel and cobalt enriched in the leaching residue are encapsulated by the large amount of smelting slag and enter the slag phase, increasing metal loss and reducing recovery. To address these issues, the present invention urgently needs to provide a method for treating high-nickel matte leaching residue. Summary of the Invention

[0003] In view of the above problems, the purpose of the present invention is to provide a high nickel matte leaching residue treatment method to solve the current treatment of high nickel matte leaching residue problems such as high energy consumption, metal dispersion, low recovery rate, etc.

[0004] The present invention provides a method for treating high-nickel matte leaching residue, comprising:

[0005] The high nickel matte leaching slag, carbonaceous reducing agent, quartz stone slagging agent, and low nickel sulfur are transported to the reduction furnace according to the preset ratio;

[0006] delivering natural gas and oxygen-enriched air to the reduction furnace in a preset ratio, and chemically reacting with the high-nickel matte leaching slag, carbonaceous reducing agent, quartz stone slagging agent, and low-nickel sulfur in the reduction furnace to generate secondary medium-nickel matte, secondary blowing slag, and flue gas;

[0007] Extracting the secondary nickel matte through a wet process system to obtain metallic nickel, cobalt, gold, silver, target, and platinum;

[0008] The secondary blowing slag and the flue gas are respectively subjected to slag removal treatment by a pyrometallurgical smelting system and an acid making system.

[0009] In addition, a preferred solution is that, before being transported to the reduction furnace, the process further comprises: performing a drying pretreatment on the high-nickel matte leaching slag, wherein the dried high-nickel matte leaching slag has a water content of 10% to 15%.

[0010] In addition, a preferred solution is that the low nickel matte is in hot or cold state; wherein,

[0011] The low-nickel matte has nickel and copper content of 0-35%, and iron content of 25-35%.

[0012] In addition, a preferred solution is that the carbonaceous reducing agent is a carbon-containing substance such as anthracite, coke, or a solid reducing agent, wherein the particle size of the carbonaceous reducing agent is 5 to 10 mm.

[0013] In addition, a preferred solution is that the quartz slag-forming agent reacts with the high-nickel matte leaching residue and the iron oxide in the low-nickel matte to generate fayalite, wherein the particle size of the quartz slag-forming agent is 5-10 mm.

[0014] In addition, a preferred solution is that the natural gas and oxygen-enriched air are sprayed into the molten pool of the reduction furnace through a spray gun arranged at the bottom of the reduction furnace, wherein the concentration of the oxygen-enriched air is 40~80%, and the air pressure of the spray gun is 1.0~1.3MPa.

[0015] In addition, a preferred solution is that, in the reduction furnace, the chemical reaction of the natural gas, oxygen-enriched air, the high-nickel matte leaching slag, the carbonaceous reducing agent, the quartz stone slagging agent, and the low-nickel sulfur comprises:

[0016] The high-valent sulfides NiS and CuS in the high-nickel matte leaching residue are decomposed into Ni3S2 and Cu2S at high temperature;

[0017] C and H2 produced by cracking CH4 in the natural gas;

[0018] The high-valent oxide Fe2O3 in the high-nickel matte leaching residue reacts with C to form FeO, and FeO reacts with SiO2 in the quartz slag-making agent to form fayalite;

[0019] The FeS in the low-nickel matte reacts with the O2 in the oxygen-enriched air to generate FeO and SO2.

[0020] In addition, a preferred solution is that the nickel matte in the secondary is formed by the mutual melting of Ni3S2, Cu2S, Co3S4, FeS and metal Au, Ag, Pt, Pd generated in the chemical reaction process.

[0021] In addition, a preferred solution is that the secondary blowing slag is formed by the mutual melting of 2FeO*SiO2 and other impurities generated during the chemical reaction.

[0022] In addition, a preferred solution is that the flue gas includes SO2 and H2O, and the temperature is 1200~1350℃;

[0023] Before the flue gas enters the acid-making system, it is first cooled by using a hood cooling method to reduce the temperature and H2O content in the flue gas;

[0024] The cooled flue gas is then subjected to dust removal treatment.

[0025] From the above technical solutions, it can be seen that the high-nickel matte leaching slag treatment method provided by the present invention has the following beneficial effects compared with the prior art:

[0026] 1) The present invention uses metal sulfides and simple substances as reducing agents, saving the amount of original carbonaceous reducing agents;

[0027] 2) The present invention utilizes the heat generated by FeS oxidation as supplementary heat for the process;

[0028] 3) The present invention utilizes a spray gun disposed at the bottom of the reduction furnace to inject natural gas and oxygen-enriched air, thereby improving reaction kinetics and accelerating the chemical reaction;

[0029] 4) Using the above method, the nickel recovery rate of the whole process is greater than 97.5%, the cobalt recovery rate is greater than 60%, and the gold, silver, platinum and palladium recovery rates reach 60% respectively.

[0030] In order to achieve the above and related purposes, one or more aspects of the present invention include the features that will be described in detail later. The following description and the accompanying drawings describe some exemplary aspects of the present invention in detail. However, these aspects indicate only some of the various ways in which the principles of the present invention can be used. In addition, the present invention is intended to include all of these aspects and their equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] By referring to the following description in conjunction with the accompanying drawings, and with a more complete understanding of the present invention, other objects and results of the present invention will become more clear and easy to understand. In the accompanying drawings:

[0032] Figure 1 Schematic diagram of the process of treating high-nickel matte leaching slag according to an embodiment of the present invention.

[0033] The same reference numerals throughout the drawings indicate similar or corresponding features or functions. Implementation Method

[0034] In the following description, for illustrative purposes, numerous specific details are set forth to provide a comprehensive understanding of one or more embodiments. However, it will be apparent that the embodiments may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form to facilitate description of one or more embodiments.

[0035] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0036] In view of the aforementioned problems in the current treatment of high-nickel matte leaching slag, such as high energy consumption, metal dispersion, and low recovery rate, the present invention provides a method for treating high-nickel matte leaching slag.

[0037] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0038] In order to illustrate the high nickel matte leaching slag treatment method provided by the present invention, Figure 1 The flowchart of the high nickel matte leaching slag treatment method according to an embodiment of the present invention is shown.

[0039] like Figure 1 As shown, the method for treating high-nickel matte leaching slag provided by the present invention comprises:

[0040] S110: transporting high nickel matte leaching slag, carbonaceous reducing agent, quartz stone slagging agent, and low nickel sulfur to the reduction furnace according to a preset ratio;

[0041] S120: delivering natural gas and oxygen-enriched air to the reduction furnace in a preset ratio, chemically reacting with the high-nickel matte leaching slag, carbonaceous reducing agent, quartz stone slagging agent, and low-nickel sulfur in the reduction furnace to generate secondary medium-nickel matte, secondary blowing slag, and flue gas;

[0042] S130: extracting the secondary nickel matte through a wet process system to obtain metallic nickel, cobalt, gold, silver, target, and platinum;

[0043] S140: Deslagging the secondary blowing slag and the flue gas is performed by a pyrometallurgical smelting system and an acid making system respectively.

[0044] The purpose of the present invention is to remove iron from the leaching slag and enrich the nickel, cobalt and precious metals in the system. A rotary metallurgical furnace is used to mix the high-nickel matte leaching slag produced by the hydrometallurgical system and the low-nickel matte produced by the pyrometallurgical system for secondary blowing. The high-valent iron oxides in the high-nickel matte leaching slag react with the sulfides in the low-nickel matte and are reduced to divalent iron oxides. Then, slag is formed with the added quartz stone to form a secondary blowing slag phase. The high-valent nickel and copper sulfides in the high-nickel matte leaching slag decompose and fuse with the sulfides in the low-nickel matte to form a matte phase as secondary medium nickel matte. The secondary medium nickel matte is sent as raw material to the subsequent precious metal extraction process for processing. The secondary blowing slag is a general solid waste and can be sold or returned to the pyrometallurgical system for recycling. The treatment method proposed by the present invention can be applied to the treatment process transformation of wet high-nickel matte leaching slag in newly built nickel smelting enterprises and old nickel smelting enterprises.

[0045] In order to achieve short-process, low-cost, low-energy-consumption, and low-investment continuous smelting of high-nickel matte leaching slag, the present invention provides a high-nickel matte leaching slag treatment method, in which high-nickel matte leaching slag and low-nickel matte are treated together in a rotary metallurgical furnace (reduction furnace), aiming to achieve efficient and economical continuous smelting.

[0046] Among them, high-nickel matte leaching slag is a by-product of the pressurized and normal-pressure leaching process of high-nickel matte. In the leaching process, most of the metallic nickel and metallic cobalt in the high-nickel matte are dissolved in the solution and then purified and enriched to become products. The remaining high-valent nickel and cobalt sulfides, high-valent iron oxides, precious metal elements, and substances insoluble in acidic solutions become leaching slag together.

[0047] In step S110, high-nickel matte leaching residue, carbonaceous reducing agent, quartz stone slagging agent, and low-nickel sulfur are all materials in the reduction furnace. The high-nickel matte leaching residue is the high-nickel matte leaching residue after wet filtration, with a moisture content of 30-35%. Drying pretreatment is required before entering the furnace, and the dried high-nickel matte leaching residue has a moisture content of 10-15%.

[0048] The low-nickel matte can be produced from the smelting process and converter slag depletion process in a conventional nickel concentrate smelting process, or from the smelting slag depletion process in a one-step nickel smelting process. The low-nickel matte contains 0-35% nickel and copper, and 25-35% iron. The low-nickel matte produced from converter slag and smelting slag depletion has a higher metal content than the low-nickel matte produced from conventional smelting processes. In embodiments of the present invention, the low-nickel matte can be hot or cooled.

[0049] The carbonaceous reducing agent may be anthracite, coke, solid reducing agent or other carbon-containing substances with a particle size of 5 to 10 mm.

[0050] Quartz slag-making agent is used. Since the iron content of high-nickel matte leaching slag is 40%-50% and that of low-nickel matte is 25%-35%, and the secondary blowing process uses an iron-silicon slag system, quartz is added. SiO2 reacts with FeO to form 2FeO*SiO2 fayalite. The particle size is 5-10mm.

[0051] In the embodiment of the present invention, high-nickel matte leaching slag, cold low-nickel sulfur, carbonaceous reducing agent, and quartz stone slagging agent are quantitatively metered according to metallurgical calculations and then added to the furnace via a belt conveyor. Hot low-nickel sulfur is then transported into the furnace via a container and crane.

[0052] In step S120, the natural gas and oxygen-enriched air are sprayed into the molten pool of the reduction furnace through a spray gun provided at the bottom of the reduction furnace. According to metallurgical calculation results, the concentration of the oxygen-enriched air is 40-80%, and the air pressure of the spray gun is 1.0-1.3 MPa.

[0053] Step S120 also includes a smelting process, in which the materials added to the furnace undergo chemical reactions of dehydration, decomposition, oxidation, and reduction under the agitation of natural gas and oxygen-enriched air. The high-valent sulfides NiS and CuS in the high-nickel matte leaching residue decompose into Ni3S2 and Cu2S at high temperatures, and C and H2 are produced after the cracking of natural CH4. The high-valent oxide Fe2O3 in the high-nickel matte leaching residue reacts with C to form FeO, which then reacts with SiO2 in the added quartz to form 2FeO*SiO2 fayalite. FeS in the low-nickel matte reacts with O2 in the oxygen-enriched air to form FeO and SO2. The main reactions are as follows:

[0054] NiS→Ni3S2+S2↑

[0055] CuS→Cu2S+S2↑

[0056] CH4→C+2H2↑

[0057] Fe2O3+C→FeO+CO↑

[0058] S2+O2→SO2↑

[0059] CO+O2→CO2↑

[0060] FeS+O2→FeO+SO2↑

[0061] FeO + SiO2→2FeO*SiO2

[0062] All materials undergo the aforementioned reactions to form secondary nickel matte, secondary converting slag, and flue gas. Ni3S2, Cu2S, Co3S4, FeS, and precious metals Au, Ag, Pt, and Pd generated during the reaction fuse together to form secondary nickel matte, which is then sent to a wet process system for extraction of precious metals, nickel, and cobalt. 2FeO*SiO2 and other impurities generated during the reaction fuse together to form secondary converting slag, which is returned to the slag depletion process of the pyrometallurgical smelting system.

[0063] In the above reaction, the matte phase in the nickel matte and the added carbonaceous reducing agent reduce the Fe2O3 in the leached slag to FeO, which reacts with quartz to form 2FeO*SiO2. The slag has a melting point of 1100-1200°C. If hot low-nickel matte is used, the heat input during the smelting process also increases the sensible heat of the melt. The FeS in the low-nickel matte reacts with the injected oxygen-enriched air, generating oxidation heat and adding heat to the reduction process.

[0064] Compared with the prior art, which has a large amount of smelting slag and carries away a large amount of precious metals, the present invention processes high-nickel matte leaching slag together with low-nickel matte, resulting in a small amount of secondary blowing slag, and thus carries away a small amount of precious metals.

[0065] In step S130 and step S140, the melt is discharged, and the secondary nickel matte and the secondary blowing slag are separated into layers in the furnace due to their different densities and then discharged through the discharge ports respectively.

[0066] Flue gas treatment: Due to the use of natural gas, coal, and chemical reactions, the generated flue gas contains SO2 and H2O, and its temperature ranges from 1200°C to 1350°C. The flue gas is cooled by air exchange within the hood, which simultaneously reduces the H2O content and dew point. The cooled flue gas, which contains SO2, undergoes dust removal and is then fed to the acid production system.

[0067] In the implementation of the present invention, high-nickel matte leaching slag, quartz, carbonaceous reducing agent, and low-nickel matte are added to a rotary metallurgical furnace for secondary blowing, reduction and smelting. The produced reduced slag is discharged regularly and then returned to the previous slag treatment process. A single layer of spray guns is arranged in the length direction of one side of the metallurgical furnace, with the height located at the slag layer. 1 to 10 spray guns can be set to spray oxygen-enriched air with an oxygen concentration of 30 to 80%. By adopting the treatment method of the present invention, a nickel recovery rate of more than 97.5%, a cobalt recovery rate of more than 60%, and a gold, silver, platinum and palladium recovery rate of 60% can be achieved in the combined full-process of pyrometallurgy and hydrometallurgy.

[0068] It can be seen from the above embodiments that the method for treating high-nickel matte leaching slag provided by the present invention uses metal sulfides and elemental substances as reducing agents, thereby saving the amount of primary carbonaceous reducing agent used; by using a spray gun arranged at the bottom of the reduction furnace to inject natural gas and oxygen-enriched air, the reaction kinetic conditions are improved and the chemical reaction is accelerated; using the above method, the nickel recovery rate of the whole process is greater than 97.5%, the cobalt recovery rate is greater than 60%, and the gold, silver, platinum and palladium recovery rates reach 60%, respectively, thereby realizing a short process, low cost, low energy consumption, and low investment continuous smelting of high-nickel matte leaching slag.

[0069] The above description of the method for treating high-nickel matte leaching residue according to the present invention is described by way of example with reference to the accompanying drawings. However, those skilled in the art will appreciate that various modifications may be made to the method for treating high-nickel matte leaching residue according to the present invention without departing from the scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A method for treating high nickel matte leaching residue, characterized in that: include: The high-nickel matte leaching residue, carbonaceous reducing agent, quartz stone slagging agent, and low-nickel matte are transported to the reduction furnace according to the preset ratio; delivering natural gas and oxygen-enriched air to the reduction furnace in a preset ratio, and chemically reacting with the high-nickel matte leaching slag, carbonaceous reducing agent, quartz stone slagging agent, and low-nickel matte in the reduction furnace to generate secondary medium-nickel matte, secondary blowing slag, and flue gas; Extracting the secondary nickel matte through a wet process system to obtain metallic nickel, cobalt, gold, silver, target, and platinum; Deslagging the secondary blowing slag and the flue gas respectively through a pyrometallurgical smelting system and an acid-making system; In the reduction furnace, the chemical reactions occurring among the natural gas, oxygen-enriched air, the high-nickel matte leaching slag, the carbonaceous reducing agent, the quartz stone slagging agent, and the low-nickel matte include: The high-valent sulfides NiS and CuS in the high-nickel matte leaching residue are decomposed into Ni3S2 and Cu2S at high temperature; C and H2 produced by cracking CH4 in the natural gas; The high-valent oxide Fe2O3 in the high-nickel matte leaching residue reacts with C to form FeO, and FeO reacts with SiO2 in the quartz slag-making agent to form fayalite; The FeS in the low-nickel matte reacts with the O2 in the oxygen-enriched air to generate FeO and SO2.

2. The method for treating high-nickel matte leaching residue according to claim 1, wherein: Before being transported to the reduction furnace, the method further includes: performing drying pretreatment on the high-nickel matte leaching slag, wherein the dried high-nickel matte leaching slag has a water content of 10% to 15%.

3. The method for treating high nickel matte leaching residue according to claim 1, wherein: The low nickel matte is in hot or cold state; wherein, The low-nickel matte has nickel and copper content of 0-35%, and iron content of 25-35%.

4. The method for treating high-nickel matte leaching residue according to claim 1, wherein: The carbonaceous reducing agent is anthracite or coke, wherein the particle size of the carbonaceous reducing agent is 5-10 mm.

5. The method for treating high-nickel matte leaching residue according to claim 1, wherein: The quartz slag-forming agent reacts with the high-nickel matte leaching residue and the iron oxide in the low-nickel matte to generate fayalite, wherein the particle size of the quartz slag-forming agent is 5-10 mm.

6. The method for treating high-nickel matte leaching residue according to claim 1, wherein: The natural gas and oxygen-enriched air are sprayed into the molten pool of the reduction furnace through a spray gun arranged at the bottom of the reduction furnace, wherein the concentration of the oxygen-enriched air is 40-80%, and the air pressure of the spray gun is 1.0-1.3 MPa.

7. The method for treating high-nickel matte leaching residue according to claim 1, wherein: The secondary nickel matte is formed by the mutual melting of Ni3S2, Cu2S, Co3S4, FeS and metal Au, Ag, Pt, Pd generated in the chemical reaction process.

8. The method for treating high-nickel matte leaching residue according to claim 1, wherein: The secondary blowing slag is 2FeO generated during the chemical reaction SiO2 and other impurities are melted together.

9. The method for treating high-nickel matte leaching residue according to claim 1, wherein: The flue gas includes SO2 and H2O, and has a temperature of 1200-1350°C; Before the flue gas enters the acid-making system, it is first cooled by using a hood cooling method to reduce the temperature and H2O content in the flue gas; The cooled flue gas is then subjected to dust removal treatment.

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