Method and device for treating laterite-nickel ore tailings

Abstract

The invention discloses a method and device for treating laterite-nickel ore tailings, and the method comprises the steps that the laterite-nickel ore tailings and a reducing agent are mixed to obtain mixed slag; carrying out granulation treatment on the mixed slag so as to obtain granular mixed slag; carrying out drying treatment on the granular mixed slag so as to obtain dried particles; carrying out roasting desulfurization treatment on the dry particles to obtain high-temperature roasted sand and roasted flue gas; carrying out cooling treatment on the high-temperature calcine to obtain an iron calcine crude product; and carrying out acid making treatment on the roasting flue gas. Therefore, by means of the treatment method, the laterite-nickel ore tailings are treated into the iron calcine crude product and the industrial sulfuric acid, environmental pollution is reduced, cyclic utilization of resources is achieved, and economic benefits are improved.

Description

Technical Field

[0001] The present application relates to the technical field of solid waste utilization, and in particular, to a method for treating laterite nickel ore tailings and a treatment device thereof. Background Art

[0002] Nickel ore resources are mainly divided into nickel sulfide ore and laterite nickel ore. With the large-scale use of high-grade nickel sulfide ore and the growing demand for nickel and cobalt materials in new energy storage and other fields, the efficient development and utilization of laterite nickel ore has become particularly important. Laterite nickel ore mainly includes limonite type, transition layer and rotten rock layer. Among them, the rotten rock layer laterite nickel ore is regarded as a high-grade ore due to its high nickel content. It can be used to prepare products such as nickel iron and matte nickel through pyrometallurgical process. In contrast, limonite-type laterite nickel ore is mainly located in the upper part of the ore deposit, and its nickel content is relatively low, usually between 0.6% and 1.2%, which belongs to medium and low grade laterite nickel ore. For medium and low grade laterite nickel ore, high pressure acid leaching process is an effective treatment method that can improve the utilization rate of nickel. However, the treatment method of high pressure acid leaching tailings of laterite nickel ore needs to be further improved.

[0003] It should be noted that the above statements are only used to provide background technical information related to the present application and do not necessarily constitute prior art. Summary of the invention

[0004] In a first aspect of the present application, the present application provides a method for treating laterite nickel ore tailings, comprising:

[0005] mixing the laterite nickel ore tailings and a reducing agent to obtain mixed slag;

[0006] Granulating the mixed slag to obtain granular mixed slag;

[0007] Drying the granular mixed slag to obtain dry granules;

[0008] The dried particles are subjected to roasting and desulfurization treatment to obtain high-temperature roasted sand and roasting flue gas;

[0009] Cooling the high-temperature roasted sand to obtain a crude iron roasted sand product;

[0010] The roasting flue gas is subjected to acid production treatment.

[0011] Therefore, the present invention processes the laterite nickel ore tailings into crude iron roasted sand and industrial sulfuric acid through the above-mentioned processing method, thereby reducing environmental pollution, realizing the recycling of resources, and improving economic benefits.

[0012] In some embodiments, the acid-making treatment of the roasting flue gas further includes performing a secondary combustion treatment on the roasting flue gas. Thus, the residual combustible material in the roasting flue gas can be subjected to secondary combustion, thereby reducing the emission of harmful gases. At the same time, the heat energy generated during the secondary combustion process can be used for the drying process of the granular mixed slag, thereby reducing the overall energy consumption in the production process.

[0013] In some embodiments, the dry mass ratio of the reducing agent to the laterite nickel ore tailings is (0.02-0.05): 1. Thus, the mass ratio of the reducing agent to the tailings dry mass is controlled to optimize the reduction reaction, thereby improving the recovery rate of iron.

[0014] In some embodiments, the reducing agent includes at least one of pulverized coal, coke, coal, and blue carbon. Thus, an appropriate reducing agent is selected to optimize the reduction reaction, thereby improving the recovery rate of iron.

[0015] In some embodiments, a chain grate is used to dry the granular mixed slag. Thus, by utilizing the production characteristics of the chain grate, such as continuous mixed slag conveying, uniform hot air distribution, and a forced ventilation system, the mixed slag can not only be dehydrated, but also the bonding strength between the particles of the mixed slag can be increased through heat treatment and mechanical action. This increase in bonding strength helps to reduce the generation of fine powder, thereby reducing the "ringing" phenomenon caused by powder aggregation during the subsequent rotary kiln roasting process of the mixed slag, and improving the stability and production safety of the subsequent roasting process.

[0016] In some embodiments, the granular mixed slag in the chain grate is laid with a thickness of 100 mm to 300 mm. Therefore, selecting a suitable laying thickness helps to increase the contact area between the hot air and the mixed slag, thereby improving the heat exchange efficiency, avoiding the problem of uneven drying of the internal particles due to an excessively thick mixed slag layer, and also preventing the waste of heat energy caused by an excessively thin mixed slag layer.

[0017] In some embodiments, the drying step includes sequentially performing air blast drying, exhaust air drying, and preheat drying.

[0018] In some embodiments, the drying process satisfies at least one of the following conditions:

[0019] The hot air temperature of the blast drying process is 220°C-320°C, and the drying time of the blast drying process is 2min-6min;

[0020] The hot air temperature of the exhaust drying process is 240°C-340°C, and the drying time of the exhaust drying process is 1min-5min;

[0021] The hot air temperature of the preheating drying process is 400° C.-750° C., and the drying time of the exhaust drying process is 5 min-20 min.

[0022] Therefore, according to the characteristics of the mixed slag to be dried and the drying requirements, the hot air temperature and the drying time during the drying process are controlled to avoid over-drying or under-drying of the mixed slag, thereby improving the drying efficiency.

[0023] In some embodiments, the hot air for the blast drying process comes from a hot air furnace. Thus, using a hot air furnace as a source of hot air for the blast drying process can provide a stable and controllable heat source and optimize the thermal efficiency of the drying process.

[0024] In some embodiments, the hot air for the exhaust drying process comes from a hot air furnace. Thus, using a hot air furnace as a source of hot air for the exhaust drying process can provide a stable and controllable heat source and optimize the thermal efficiency of the drying process.

[0025] In some embodiments, the hot air direction of the blast drying process is opposite to the hot air direction of the exhaust drying process. Thus, by controlling the wind directions of the blast drying process and the exhaust drying process, the heat exchange efficiency in the drying process is optimized, and the drying speed and quality are improved.

[0026] In some embodiments, the hot air for the preheating and drying treatment comes from the waste gas generated after the high-temperature roasted sand is cooled, and / or the waste gas generated after the roasting flue gas is subjected to secondary combustion.

[0027] Thus, the waste gas reaches the hot air temperature of the preheating and drying treatment after being heated and / or cooled. The waste gas generated after the high-temperature roasted sand is cooled and / or the waste gas generated after the roasting flue gas is subjected to secondary combustion treatment is used as the hot air of the preheating and drying treatment, thereby improving the efficiency of energy reuse and reducing energy waste.

[0028] In some embodiments, the granulated mixed slag satisfies at least one of the following conditions:

[0029] The shape of the granular mixed slag includes at least one of a sphere, a cylinder, a cube, and a cuboid;

[0030] The length of a single particle of the granular mixed slag is 1 mm to 100 mm, or the diameter of a single particle is 1 mm to 100 mm;

[0031] The compressive strength of the granular mixed slag is greater than or equal to 10N / m 2 .

[0032] Therefore, by controlling the shape, size and compressive strength of the mixed slag particles, the stability of the mixed slag during the drying and roasting desulfurization treatment processes is improved, the generation of dust is reduced, and the breakage rate of the mixed slag particles is reduced.

[0033] In some embodiments, the roasting temperature of the roasting desulfurization treatment is 950° C.-1150° C. Thus, by controlling the temperature of roasting desulfurization, the conversion rate of ferrous ions and the efficiency of the desulfurization reaction are improved, while avoiding equipment loss caused by excessive high temperature.

[0034] In some embodiments, the method further comprises drying the mixed slag at a drying temperature of 350° C. to 450° C. Thus, the laterite nickel ore tailings and the reducing agent are pre-dried to reduce their water content in advance, providing a basis for subsequent granulation of the mixed slag.

[0035] In some embodiments, the water content of the mixed slag is 15%-18%. Thus, the mixed slag has a suitable water content, which helps to improve the success rate of subsequent granulation of the mixed slag.

[0036] In some embodiments, the particle size of the high-temperature roasted sand is greater than or equal to 5 mm, thereby meeting the use standard of crude iron roasted sand.

[0037] In some embodiments, the cooling treatment of the high temperature roasted sand includes at least one cold air treatment. Thus, the cold air treatment can quickly reduce the temperature of the high temperature roasted sand.

[0038] In a second aspect of the present application, the present application provides a processing device used in a method for processing laterite nickel ore tailings, the processing device comprising:

[0039] A mixing device, wherein the mixing device is used to mix the laterite nickel ore tailings and the reducing agent to obtain mixed slag;

[0040] A granulating device, wherein the granulating device is used to granulate the mixed slag to obtain granular mixed slag;

[0041] A drying device, the drying device is used to dry the granular mixed slag to obtain dry particles;

[0042] A roasting device, wherein the roasting device is used to perform a roasting and desulfurization treatment on the dried particles to obtain high-temperature roasted sand and roasting flue gas;

[0043] A cooling device is used to cool the high-temperature roasted sand to obtain a crude iron roasted sand product.

[0044] In some embodiments, the processing device further includes a heat exchange device, which is used to heat up the waste gas generated after the high-temperature roasted sand is cooled, and / or the heat exchange device is used to cool down the waste gas generated after the roasting flue gas is secondary burned. Thus, the waste gas is heated or cooled by the heat exchange device, thereby improving the recovery efficiency of heat energy and reducing energy waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0046] Figure 1 It is a schematic diagram of the process flow of a method for treating laterite nickel ore tailings in one embodiment of the present application.

[0047] Figure 2 It is a schematic diagram of the system structure of a method for treating laterite nickel ore tailings in one embodiment of the present application. DETAILED DESCRIPTION

[0048] Hereinafter, a method for treating laterite nickel ore tailings and an embodiment of a treatment device thereof of the present application will be specifically disclosed with appropriate reference to the accompanying drawings. However, there may be cases where unnecessary detailed descriptions are omitted. For example, there are cases where detailed descriptions of well-known matters and repeated descriptions of actually the same structures are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following description are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0049] " Scope " disclosed in the present application is limited in the form of lower limit and upper limit, and a given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a special range. The scope limited in this way can be to include end values ​​or not include end values, and can be combined arbitrarily, that is, any lower limit can form a scope with any upper limit combination. For example, if the scope of 60-120 and 80-110 is listed for a particular parameter, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​1 and 2 listed, and if the maximum range values ​​3,4 and 5 are listed, the following scope can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present application, unless otherwise specified, the numerical range "ab" represents the abbreviation of any real number combination between a and b, wherein a and b are real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0050] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0051] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0052] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by technicians in the technical field to which this application belongs; the terms used in this application are only for the purpose of describing specific embodiments and are not intended to limit this application; unless otherwise specified, the numerical values ​​of the parameters mentioned in this application can be measured using various measurement methods commonly used in the art (for example, they can be tested according to the methods given in the embodiments of this application).

[0053] In the description of the present application, "A and / or B" may include the case of A alone, the case of B alone, or any of the cases of A and B, where A and B are only used for examples and may be any technical feature connected by "and / or" in the present application.

[0054] The high-pressure acid leaching process of laterite nickel ore is carried out under high temperature and high pressure conditions, using sulfuric acid or nitric acid as the leaching medium. By finely controlling the process parameters, most of the iron and aluminum elements in the laterite nickel ore are hydrolyzed into the acid leaching tailings, while nickel and cobalt are selectively leached into the leachate. After the leachate is neutralized and impurity-removed, a high-quality nickel and cobalt solution can be obtained. Finally, the nickel and cobalt solution can produce products such as nickel cobalt hydroxide (MHP) or nickel cobalt sulfide (MSP) through a hydrolysis precipitation process. The advantage of the high-pressure acid leaching process lies in its excellent leaching selectivity and high nickel and cobalt leaching rates. However, this process will produce a large amount of high-iron and high-sulfur leaching tailings. At present, the treatment methods of these leaching tailings are mainly storage or deep-sea landfill treatment, which may not only cause environmental pollution, but also lead to waste of resources. Therefore, how to further optimize the tailings after high-pressure acid leaching of laterite nickel ore to reduce environmental pollution and waste of resources is a problem that needs to be solved urgently.

[0055] In a first aspect of the present application, the present application provides a method for treating laterite nickel ore tailings, referring to Figure 1 , the method comprising:

[0056] S100: mixing the laterite nickel ore tailings and the reducing agent to obtain mixed slag.

[0057] The laterite nickel tailings used in the present application are tailings after high-pressure acid leaching of laterite nickel ore. Specifically, the laterite nickel tailings are solid wastes remaining after the extraction of nickel and cobalt elements, and the tailings contain multiple elements. In some embodiments, the main elements on a dry basis in the laterite nickel tailings include Fe, Si, Al, Ca, Mg, S, P, Ni, Cr, etc.

[0058] In some embodiments, the dry mass ratio of the reducing agent to the laterite nickel ore tailings is (0.02-0.05): 1. Thus, the mass ratio of the reducing agent to the tailings dry mass is controlled to optimize the reduction reaction, thereby improving the recovery rate of iron.

[0059] As an example, the dry mass ratio of the reducing agent to the laterite nickel ore tailings may be 0.02:1, 0.03:1, 0.04:1 or 0.05:1.

[0060] In some embodiments, the reducing agent includes at least one of pulverized coal, coke, coal, and blue carbon. Thus, an appropriate reducing agent is selected to optimize the reduction reaction, thereby increasing the recovery rate of iron.

[0061] In some embodiments, the mixed slag needs to be dried at a temperature of 350° C.-450° C. Since the water content of the laterite nickel tailings is in the range of 30%-35%, it is pre-dried before use to reduce its water content, providing a basis for subsequent granulation of the mixed slag.

[0062] As an example, the drying temperature may be 350°C, 370°C, 390°C, 410°C, 430°C, or 450°C.

[0063] In some embodiments, the water content of the mixed slag is 15%-18%. Thus, the mixed slag has a suitable water content, which helps to improve the success rate of subsequent granulation of the mixed slag.

[0064] As an example, the moisture content of the mixed slag may be 15%, 16%, 17% or 18%.

[0065] S200: granulating the mixed slag to obtain granular mixed slag.

[0066] In some embodiments, the granulated mixed slag satisfies at least one of the following conditions:

[0067] The shape of the granular mixed slag includes at least one of a sphere, a cylinder, a cube, and a cuboid;

[0068] The length of a single particle of the granular mixed slag is 1 mm to 100 mm, or the diameter of a single particle is 1 mm to 100 mm;

[0069] The compressive strength of the granular mixed slag is greater than or equal to 10N / m 2 .

[0070] Therefore, by controlling the shape, size and compressive strength of the mixed slag particles, the stability of the mixed slag during the drying and roasting desulfurization treatment processes is improved, the generation of dust is reduced, and the breakage rate of the mixed slag particles is reduced.

[0071] As an example, the length of a single particle of the granulated mixed slag may be 1 mm, 5 mm, 10 mm, 20 mm, 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm or 100 mm.

[0072] As an example, the diameter of a single particle of the granulated mixed slag may be 1 mm, 5 mm, 10 mm, 20 mm, 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm or 100 mm.

[0073] As an example, the compressive strength of the granular mixed slag is tested using a compressive strength pressure testing machine. The compressive strength of the granular mixed slag includes but is not limited to 10N / m 2 , 15N / m 2 , 20N / m 2 、30N / m 2 , 40N / m 2 , 60N / m 2、80N / m 2 The compressive strength of the granular mixed slag is screened according to actual use needs.

[0074] In some embodiments, the granular mixed slag satisfies the following conditions at the same time: the shape of the granular mixed slag is spherical; the diameter of a single particle of the granular mixed slag is 1 mm-100 mm; the compressive strength of the granular mixed slag is greater than or equal to 10 N / m 2 .

[0075] In some embodiments, the granular mixed slag satisfies the following conditions at the same time: the shape of the granular mixed slag is cylindrical; the length of a single particle of the granular mixed slag is 1 mm-100 mm, and the diameter of a single particle is 1 mm-100 mm; the compressive strength of the granular mixed slag is greater than or equal to 10 N / m 2 .

[0076] S300: Drying the granular mixed slag to obtain dry granules.

[0077] In some embodiments, a chain grate is used to dry the granular mixed slag. Thus, by utilizing the production characteristics of the chain grate, such as continuous mixed slag conveying, uniform hot air distribution, and a forced ventilation system, the moisture in the mixed slag can be removed, and the bonding strength between the particles of the mixed slag can be increased through heat treatment and mechanical action. This increase in bonding strength helps to reduce the generation of fine powder, thereby reducing the "ringing" phenomenon caused by powder aggregation during the subsequent rotary kiln roasting process of the mixed slag, and improving the stability and production safety of the subsequent roasting process.

[0078] In some embodiments, the granular mixed slag in the chain grate is laid with a thickness of 100 mm to 300 mm. Therefore, selecting a suitable laying thickness helps to increase the contact area between the hot air and the mixed slag, thereby improving the heat exchange efficiency, avoiding the problem of uneven drying of the internal particles caused by an excessively thick mixed slag layer, and also preventing the waste of heat energy caused by an excessively thin mixed slag layer.

[0079] As an example, the laying thickness of the granular mixed slag in the chain grate may be 100 mm, 150 mm, 200 mm, 250 mm or 300 mm.

[0080] In some embodiments, the drying step includes sequentially performing a forced air drying process, a suction air drying process, and a preheating drying process.

[0081] In some embodiments, the drying step satisfies at least one of the following conditions:

[0082] The hot air temperature of the blast drying process is 220℃-320℃, and the drying time of the blast drying process is 2min-6min;

[0083] The hot air temperature of the exhaust drying process is 240℃-340℃, and the drying time of the exhaust drying process is 1min-5min;

[0084] The hot air temperature of the preheating drying treatment is 400°C-750°C, and the drying time of the exhaust drying treatment is 5min-20min.

[0085] Therefore, according to the characteristics of the mixed slag to be dried and the drying requirements, the hot air temperature and the drying time during the drying process are controlled to avoid over-drying or under-drying of the mixed slag and improve the drying efficiency.

[0086] As an example, the hot air temperature of the blast drying process may be 220°C, 240°C, 260°C, 280°C, 300°C or 320°C.

[0087] As an example, the drying time of the forced air drying process may be 2 min, 3 min, 4 min, 5 min or 6 min.

[0088] As an example, the hot air temperature of the exhaust drying process may be 240°C, 260°C, 280°C, 300°C, 320°C or 340°C.

[0089] As an example, the drying time of the exhaust drying process may be 1 min, 2 min, 3 min, 4 min or 5 min.

[0090] As an example, the hot air temperature of the preheat drying process may be 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C or 750°C.

[0091] As an example, the drying time of the preheat drying process may be 5 min, 10 min, 15 min or 20 min.

[0092] In some embodiments, the drying step needs to meet the following conditions at the same time: the hot air temperature of the blast drying treatment is 220℃-320℃, and the drying time of the blast drying treatment is 2min-6min; the hot air temperature of the exhaust drying treatment is 240℃-340℃, and the drying time of the exhaust drying treatment is 1min-5min; the hot air temperature of the preheating drying treatment is 400℃-750℃, and the drying time of the exhaust drying treatment is 5min-20min. Therefore, the drying step is divided into three stages. In the blast drying stage, the moisture on the surface of the granular mixed slag is first removed; then the temperature is increased, and in the exhaust drying stage, the moisture in the granular mixed slag is further reduced; finally, the temperature is continued to be increased, which helps to completely remove the moisture in the deep layer of the granular mixed slag, and at the same time preheat the mixed slag to prepare for the next stage of roasting and desulfurization. Through this staged drying strategy, the entire drying process can not only adapt to the moisture removal needs of different stages, but also optimize energy use, thereby achieving the goal of energy saving and consumption reduction. In addition, this gradual heating method helps to reduce thermal stress and avoid cracking or damage of the granular mixed slag due to sudden temperature changes.

[0093] In some embodiments, the hot air for the blast drying process comes from a hot air furnace. Thus, using a hot air furnace as a source of hot air for the blast drying process can provide a stable and controllable heat source and optimize the thermal efficiency of the drying process.

[0094] In some embodiments, the hot air for the exhaust drying process comes from a hot air furnace. Therefore, using a hot air furnace as a source of hot air for the exhaust drying process can provide a stable and controllable heat source and optimize the thermal efficiency of the drying process.

[0095] In some embodiments, the hot air direction of the forced air drying process is opposite to that of the exhaust air drying process. Thus, by controlling the wind directions of the forced air drying process and the exhaust air drying process, the heat exchange efficiency in the drying process is optimized, and the drying speed and quality are improved.

[0096] In some embodiments, the hot air for the preheating and drying process is derived from the waste gas generated after the high-temperature roasted sand is cooled, and / or the waste gas generated after the roasting flue gas is subjected to secondary combustion. Thus, the waste gas reaches the hot air temperature for the preheating and drying process after heating and / or cooling. The waste gas generated after the high-temperature roasted sand is cooled, and / or the waste gas generated after the roasting flue gas is subjected to secondary combustion as the hot air for the preheating and drying process, thereby improving the efficiency of energy reuse and reducing energy waste.

[0097] S400: The dried particles are subjected to roasting and desulfurization treatment to obtain high-temperature roasted sand and roasting flue gas.

[0098] In some embodiments, the roasting temperature of the roasting desulfurization treatment is 950° C.-1150° C. Thus, by controlling the temperature of the roasting desulfurization, the conversion rate of ferrous ions and the efficiency of the desulfurization reaction are improved, while avoiding equipment loss caused by excessive high temperature.

[0099] The following chemical reactions occur during the roasting and desulfurization process of dry particles:

[0100] 2C+O 2 (g)=2CO(g)↑

[0101] 3Fe 2 O 3 +C=2Fe 3 O 4 +CO(g)↑

[0102] Fe 3 O 4 +CO(g)=3FeO+CO 2 (g)↑

[0103] 2Al 2 (SO 4 ) 3 =2Al 2 O 3 +6SO 2 (g)↑+3O 2 (g)↑

[0104] CaSO 4 +2C=CaS+2CO 2 (g)↑

[0105] 3CaSO 4 +CaS=4CaO+4SO 2 (g)↑

[0106] CaSO 4 +2Fe 3 O 4 =CaO+3Fe 2 O 3 +SO 2 (g)↑

[0107] Fe in mixed slag 2 O 3 During the calcination process, it is reduced to Fe 3 O 4 or FeO, using Fe 2+ To complete the desulfurization reaction of sulfate, this process can occur in a lower temperature range (950℃-1150℃), which not only improves the desulfurization rate, but also avoids the problem of soft melting ring of mixed slag caused by high-temperature roasting.

[0108] As an example, the calcination temperature of the calcination desulfurization treatment may be 950°C, 1000°C, 1050°C, 1100°C or 1150°C.

[0109] In some embodiments, the roasting desulfurization process step requires fuel to provide thermal energy.

[0110] In some embodiments, the fuel includes at least one of sulfur, long flame coal, pulverized coal, natural gas, and hydrogen.

[0111] In some embodiments, the fuel injection rate per unit time is 1-3 t / h.

[0112] As an example, the fuel injection rate per unit time may be 1 t / h, 2 t / h or 3 t / h.

[0113] In some embodiments, the fuel needs combustion-supporting air, and the combustion-supporting air includes oxygen-enriched air with an oxygen concentration of 21%-23%, thereby improving the combustion efficiency during the roasting and desulfurization process.

[0114] As an example, the oxygen concentration of the oxygen enriched air may be 21%, 22%, or 23%.

[0115] In some embodiments, the combustion-supporting wind speed is 180 m / s-300 m / s.

[0116] As an example, the combustion-supporting wind speed may be 180 m / s, 200 m / s, 220 m / s, 240 m / s, 260 m / s, 280 m / s or 300 m / s.

[0117] S500: Cooling the high-temperature roasted sand to obtain crude iron roasted sand.

[0118] In some embodiments, the particle size of the high temperature roasted sand is greater than or equal to 5 mm, thereby meeting the use standard of crude iron roasted sand.

[0119] As an example, the particle size of the high temperature roasted sand can be 5 mm, 7 mm, 9 mm, 10 mm, 20 mm, 40 mm, 60 mm or 100 mm.

[0120] In some embodiments, the cooling treatment of the high temperature roasted sand includes at least one cold wind treatment. Thus, by cooling at least one cold wind treatment, the temperature of the high temperature roasted sand can be quickly reduced.

[0121] As an example, the cooling treatment of the high-temperature roasted sand may include 1 cold air treatment, 2 cold air treatments, 3 cold air treatments, 4 cold air treatments, 5 cold air treatments, and 6 cold air treatments.

[0122] In some embodiments, the waste gas generated after the high-temperature roasted sand is cooled is heated through heat exchange and becomes the source of hot air for the preheating and drying process.

[0123] In some embodiments, the temperature of the cold exhaust gas after heat exchange reaches 400° C.-750° C. Thus, the use temperature of the hot air for preheating and drying treatment is reached.

[0124] As an example, the temperature of the cold exhaust gas after heat exchange may be 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C or 750°C.

[0125] In some embodiments, the iron grade of the crude iron roasted sand product is increased to 40%-50%. As a result, the crude iron roasted sand product has met the standard of being a low-grade iron ore resource due to the increase in iron grade. The crude iron roasted sand product can directly enter the subsequent smelting process for further refining. In particular, the crude iron roasted sand product is suitable for processing using advanced non-blast furnace ironmaking technologies such as Hismelt. These modern processes can efficiently convert crude iron roasted sand products into high-quality molten iron, improve the overall resource utilization value, and achieve dual benefits of economy and environmental protection.

[0126] S600: Acid treatment is performed on the roasting flue gas.

[0127] In some embodiments, the acid-making treatment of the roasting flue gas further includes performing a secondary combustion treatment on the roasting flue gas. Thus, the residual combustible material in the roasting flue gas can be subjected to secondary combustion, thereby reducing the emission of harmful gases. At the same time, the heat energy generated during the secondary combustion process can be used for the drying process of the granular mixed slag, thereby reducing the overall energy consumption in the production process. The chemical reaction of the secondary combustion is: 2CO(g)+O 2 (g) = 2CO 2 (g)↑.

[0128] In some embodiments, the hot exhaust gas generated by the secondary combustion is heat exchanged through an air-cooled heat exchanger, whereby the heat energy of the hot exhaust gas is sent to the preheating and drying step of the chain grate machine for use, thereby realizing the reuse of the heat source.

[0129] In some embodiments, the cooling gas for heat exchange with the hot waste gas comes from the cold waste gas generated after the high-temperature roasted sand is cooled, thereby the cold waste gas is reused and energy is saved.

[0130] In some embodiments, the hot exhaust gas is cooled to 350° C.-450° C. and enters a dust collection system for dust removal.

[0131] As an example, the hot exhaust gas is cooled to 350°C, 370°C, 390°C, 410°C, 430°C or 450°C.

[0132] In some embodiments, the SO in the hot exhaust gas after dust removal is 2 The content is 3.5%-4%. 2 Industrial sulfuric acid can be prepared through the "one turn and one suction" process.

[0133] Thus, through the aforementioned treatment method: 1. Mixing treatment, first mix the laterite nickel ore tailings and the reducing agent, so that the two are evenly mixed, and the subsequent reduction efficiency is improved; 2. Granulation treatment, the mixed slag after granulation has better formability and fluidity, so as to facilitate subsequent drying treatment and roasting desulfurization treatment; 3. Drying treatment, reduce material weight, reduce energy consumption, prevent agglomeration and adhesion during roasting, and improve roasting efficiency; 4. Roasting desulfurization treatment, remove sulfide at high temperature, reduce pollutant emissions in the air, and improve the grade of iron ore at the same time, which is convenient for subsequent processing; 5. Cooling treatment, reduce the temperature of high-temperature roasting sand, facilitate subsequent storage and transportation, reduce heat energy loss, and improve the energy efficiency of the entire process; 6. Acid production treatment, convert SO and other components in the roasting flue gas into useful chemical raw materials such as sulfuric acid, realize the recycling of resources, and reduce environmental pollution. Therefore, the present invention processes the laterite nickel ore tailings into iron roasting sand crude products and industrial sulfuric acid through the aforementioned treatment method, reduces environmental pollution, realizes the recycling of resources, and improves economic benefits.

[0134] In a second aspect of the present application, the present application provides a processing device used in a method for processing laterite nickel ore tailings, the processing device comprising:

[0135] A mixing device, the mixing device is used to mix the laterite nickel ore tailings and the reducing agent to obtain mixed slag;

[0136] A granulating device, which is used to granulate the mixed slag to obtain granular mixed slag;

[0137] A drying device, the drying device is used to dry the granular mixed slag to obtain dry particles;

[0138] A roasting device, which is used to perform roasting and desulfurization treatment on the dried particles to obtain high-temperature roasted sand and roasting flue gas;

[0139] The cooling device is used to cool the high-temperature roasted sand to obtain crude iron roasted sand.

[0140] The mixing device may be a double screw dryer, a rotary drying kiln or a rake steam dryer. In some embodiments, the mixing device is a double screw dryer, and the propeller blades of the dryer continuously stir the material, so that the material is dried and mixed more evenly.

[0141] As an example, the granulation device can be an extrusion granulator. Thus, the extrusion granulator is used to facilitate the formation of granular mixed slag, simplify the pretreatment process of the material, improve production efficiency, reduce process energy consumption, and save production costs.

[0142] In some embodiments, the working pressure of the extrusion granulator is 1 MPa-2.5 MPa.

[0143] As an example, the operating pressure of the extrusion granulator may be 1 MPa, 1.5 MPa, 2 MPa or 2.5 MPa.

[0144] In some embodiments, the rotation frequency of the scraper of the extrusion granulator is 5 rpm to 15 rpm.

[0145] As an example, the scraper rotation frequency of the extrusion granulator can be 5 rev / sec, 7 rev / sec, 9 rev / sec, 11 rev / sec, 13 rev / sec or 15 rev / sec.

[0146] As an example, the roasting device may be a rotary kiln.

[0147] In some embodiments, the filling rate of the dry particles in the rotary kiln is 5%-15%. In some embodiments, the roasting time of the dry particles in the rotary kiln is 10min-20min. In some embodiments, the rotation speed of the rotary kiln is 0.4rpm-1.2rpm. In some embodiments, the slope of the rotary kiln is 2%-4%.

[0148] As an example, the filling rate of the dry particles in the rotary kiln may be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14% or 15%.

[0149] As an example, the calcination time of the dried particles in the rotary kiln may be 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, 16 min, 17 min, 18 min, 19 min or 20 min.

[0150] As an example, the rotation speed of the rotary kiln may be 0.4 rpm, 0.6 rpm, 0.8 rpm, 1.0 rpm or 1.2 rpm.

[0151] As an example, the slope of the rotary kiln may be 2%, 3% or 4%.

[0152] As an example, the cooling device may be a ring cooler.

[0153] In some embodiments, the processing device further includes a heat exchange device, which is used to heat up the waste gas generated after the high-temperature roasted sand is cooled, and / or the heat exchange device is used to cool down the waste gas generated after the roasting flue gas is secondary burned. Thus, the waste gas is heated or cooled by the heat exchange device, thereby improving the recovery efficiency of heat energy and reducing energy waste.

[0154] The scheme of the present application is described below by specific examples. It should be noted that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. If no specific technology or conditions are specified in the examples, the technology or conditions described in the literature in this area or the product instructions are used. The reagents or instruments used are not specified by the manufacturer, and are all conventional products that can be obtained commercially.

[0155] Example 1

[0156] The laterite nickel ore tailings used in this embodiment are tailings of laterite nickel ore after high-pressure acid leaching.

[0157] Treatment method of laterite nickel ore tailings, combined with Figure 2 , the specific steps are as follows:

[0158] S100, laterite nickel ore tailings, includes 32% water and 68% dry basis. The main components of the dry basis are shown in Table 1:

[0159] Table 1

[0160]

[0161]

[0162] 100t of laterite nickel tailings, laterite nickel tailings and lignite powder (the mass ratio of lignite powder to laterite nickel tailings is 0.025:1) are transported to a double screw dryer (the internal temperature of the double screw dryer is 320°C) via a belt conveyor. The laterite nickel tailings and lignite powder are dried and mixed in the double screw dryer to obtain mixed slag, and the water content of the mixed slag is 17%.

[0163] S200, the mixed slag is conveyed to the extrusion granulator by a belt conveyor for granulation. The working pressure of the extrusion granulator is 2MPa, and the scraper rotation frequency is 10 rpm. The cylindrical granular mixed slag with a length and diameter of 10mm is obtained. The average compressive strength of the granular mixed slag is 12N / m 2 Finally, the qualified granular mixed slag is transported to the chain grate section by belt.

[0164] S300, the granular mixed slag is evenly distributed into a material layer with a thickness of 220 mm on the head of the chain plate of the chain grate through a distributor, and then the granular mixed slag is subjected to blast drying, exhaust drying and drying preheating treatment in sequence as the chain plate moves;

[0165] (1) Blast drying: The hot air for blast drying is generated by a hot air furnace, and the hot air is blown into the material layer by the blower fan at the bottom of the material layer, that is, the hot air passes through the material layer from bottom to top. The temperature of the hot air is 240°C, and the blast drying time is 3 minutes. After the hot air and the material layer undergo heat exchange, the airflow carries the moisture in the material layer into the upper cover of the chain grate. The exhaust gas in the upper cover of the blast drying section can be directly discharged into the atmosphere after dust removal by the furnace cover dust collector.

[0166] (2) Exhaust drying: The hot air for exhaust drying is generated by a hot air furnace and is sent into the material layer by a hot air blower at the top of the material layer, that is, the hot air passes through the material layer from top to bottom. The temperature of the hot air is 260°C and the exhaust drying time is 2 minutes. After the hot air exchanges heat with the material layer, the airflow carries the moisture in the material layer out of the chain grate.

[0167] (3) Preheating and drying treatment: The hot air for preheating and drying treatment is sent to the upper cover of the preheating and drying section after passing through the air-cooling heat exchanger. The hot air is blown into the material layer by the high-temperature fan, that is, the hot air passes through the material layer from top to bottom. The temperature of the hot air is 410°C and the preheating and drying time is 7 minutes. After the hot air exchanges heat with the material layer, the exhaust gas is discharged;

[0168] After the drying process is completed, dry particles are obtained; the chain grate conveys the dry particles to the rotary kiln roasting section through the shovel plate device and the slide plate device.

[0169] S400, the dried particles are sent to the rotary kiln (the aspect ratio of the rotary kiln is 6:1), and the dried particles roll in the circumferential direction with the rotation of the rotary kiln, and the dried particles move from the kiln tail to the kiln head. The feeding speed of the dried particles is adjusted to make the filling rate of the dried particles in the rotary kiln 10%, and the rotation speed of the rotary kiln is adjusted to 0.8rpm, and the slope of the rotary kiln is adjusted to 2%, so that the residence time of the dried particles in the rotary kiln is 13min; the kiln head of the rotary kiln is equipped with a fuel burner and a combustion-supporting air channel, which burns long bituminous coal, and the combustion-supporting air is oxygen-enriched air with an oxygen concentration of 21%; the fuel injection amount per unit time is adjusted to 2t / h, and the combustion-supporting air speed is adjusted to 200m / s, so that the temperature of the high temperature zone in the rotary kiln is 1000℃. The dried particles are roasted at high temperature to obtain high-temperature roasted sand and roasting flue gas.

[0170] S500, high temperature roasted sand is screened by the fixed screen at the kiln head of the rotary kiln. The high temperature roasted sand with a particle diameter greater than or equal to 5 mm is sent to the blast type ring cooler for cooling treatment, and the crushed material with a particle diameter less than 5 mm is returned to the mixed granulation treatment step for further granulation. The initial temperature of the high temperature roasted sand is 950°C. The high temperature roasted sand is evenly spread on the ring cooler trolley through the flat material wheel of the feed hopper. A bellows is arranged under the ring cooler trolley. The bellows blow natural wind from bottom to top into the ring cooler, thereby cooling the high temperature roasted sand and obtaining a crude iron roasted sand product.

[0171] In this embodiment, the ring cooler is divided into ring cooling section 1, ring cooling section 2, and ring cooling section 3. The ring cooling air section 1 and the ring cooling air section 2 respectively produced by the ring cooling section 1 and the ring cooling section 2 are merged into the air-cooled heat exchanger, and the 3 ring cooling air sections produced by the ring cooling section 3 are drawn out and discharged through the exhaust pipe of the ring cooler itself.

[0172] S600, the roasting flue gas produced by the rotary kiln is subjected to secondary combustion treatment in the secondary combustion chamber, so that the CO in the roasting flue gas is fully burned, and the temperature of the generated hot flue gas is 1200℃; the hot flue gas is subjected to heat exchange through the air-cooled heat exchanger, and the cooling gas of the air-cooled heat exchanger comes from the 1st section of the ring cooling air and the 2nd section of the ring cooling air produced by the 1st section of the ring cooling and the 2nd section of the ring cooling, respectively. After heat exchange, the hot flue gas becomes cooling flue gas with a temperature of 350℃, and the cooling flue gas enters the dust collection system for dust removal. After dust removal, the cooling flue gas enters the acid making system for acid making treatment, and finally obtains industrial sulfuric acid. The temperature of the ring cooling exhaust gas that passes through the air-cooled heat exchanger rises to 410℃, and this part of the hot air is transported to the preheating and drying section of the chain grate machine for use. SO in the rotary kiln flue gas produced in this embodiment 2 The content is 3.5%-4%, and industrial sulfuric acid can be prepared through the "one turn and one absorption" process.

[0173] The composition of the crude iron roasted sand was tested, and the composition is shown in Table 2:

[0174] Table 2

[0175]

[0176] As shown in Table 2, after the laterite nickel ore tailings are subjected to roasting and desulfurization treatment, the iron grade of the crude iron roasted sand can reach 44.3%, and the sulfur removal rate is 99.02%.

[0177] Example 2

[0178] The difference between Example 2 and Example 1 is that the element content of the laterite nickel ore tailings is different. The main component contents on a dry basis are shown in Table 3:

[0179] Table 3

[0180]

[0181]

[0182] The components of the crude iron roasted sand of Example 2 were detected, and the components are shown in Table 4:

[0183] Table 4

[0184]

[0185] As shown in Table 4, after the laterite nickel ore tailings are subjected to roasting and desulfurization treatment, the iron grade of the crude iron roasted sand can reach 42.65%, and the sulfur removal rate is 99.06%.

[0186] Example 3

[0187] The difference between Example 3 and Example 1 is that the mass ratio of lignite powder to laterite nickel tailings is 0.05: 1. After the laterite nickel tailings are roasted and desulfurized, the iron grade of the crude iron roasted sand can reach 44.17%, and the sulfur removal rate is 98.94%.

[0188] Example 4

[0189] The difference between Example 4 and Example 1 is that in the drying process of the granular mixed slag, a one-step drying method is adopted, that is, the drying temperature is 410° C. and the drying time is 12 minutes. After the laterite nickel ore tailings are roasted and desulfurized, the iron grade of the crude iron roasted sand can reach 40.88%, and the sulfur removal rate is 99.31%.

[0190] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A method for treating laterite nickel ore tailings, characterized in that: include: mixing the laterite nickel ore tailings and a reducing agent to obtain mixed slag; Granulating the mixed slag to obtain granular mixed slag; Drying the granular mixed slag to obtain dry granules; The dried particles are subjected to roasting and desulfurization treatment to obtain high-temperature roasted sand and roasting flue gas; Cooling the high-temperature roasted sand to obtain a crude iron roasted sand product; The roasting flue gas is subjected to acid production treatment.

2. The method according to claim 1, characterized in that: The acid-making treatment of the roasting flue gas further includes performing secondary combustion treatment on the roasting flue gas.

3. The method according to claim 1 or 2, characterized in that: The dry basis mass ratio of the reducing agent to the laterite nickel ore tailings is (0.02-0.05):1; Optionally, the reducing agent includes at least one of pulverized coal, coke, coal, and blue carbon.

4. The method according to claim 1 or 2, characterized in that: Using a chain grate to dry the granular mixed slag; Optionally, the laying thickness of the granular mixed slag in the chain grate is 100mm-300mm.

5. The method according to claim 4, characterized in that The drying process comprises sequentially performing air blast drying, exhaust air drying, and preheat drying; Optionally, the drying process satisfies at least one of the following conditions: The hot air temperature of the blast drying process is 220°C-320°C, and the drying time of the blast drying process is 2min-6min; The hot air temperature of the exhaust drying process is 240°C-340°C, and the drying time of the exhaust drying process is 1min-5min; The hot air temperature of the preheating drying process is 400° C.-750° C., and the drying time of the exhaust drying process is 5 min-20 min.

6. The method according to claim 5, characterized in that The hot air for the blast drying process comes from a hot air furnace; and / or, The hot air for the exhaust drying process comes from a hot air furnace; and / or, The hot air direction of the forced air drying process is opposite to the hot air direction of the exhaust air drying process; and / or, The hot air of the preheating and drying treatment comes from the waste gas generated after the high-temperature roasted sand is cooled, and / or the waste gas generated after the roasting flue gas is subjected to secondary combustion.

7. The method according to claim 1 or 2, characterized in that: The granular mixed slag meets at least one of the following conditions: The shape of the granular mixed slag includes at least one of a sphere, a cylinder, a cube, and a cuboid; The length of a single particle of the granular mixed slag is 1 mm to 100 mm, or the diameter of a single particle is 1 mm to 100 mm; The compressive strength of the granular mixed slag is greater than or equal to 10N / m 2 .

8. The method according to claim 1 or 2, characterized in that: The roasting temperature of the roasting desulfurization treatment is 950°C-1150°C.

9. The method according to claim 1 or 2, characterized in that: The method further comprises drying the mixed slag at a drying temperature of 350° C. to 450° C.; Optionally, the water content of the mixed slag is 15%-18%.

10. The method according to claim 1 or 2, characterized in that: The particle size of the high temperature roasted sand is greater than or equal to 5 mm; and / or, The cooling treatment of the high temperature roasted sand includes at least one cold air treatment.

11. A processing device used in the method for processing laterite nickel ore tailings according to any one of claims 1 to 10, characterized in that: The processing device comprises: A mixing device, wherein the mixing device is used to mix the laterite nickel ore tailings and the reducing agent to obtain mixed slag; A granulating device, wherein the granulating device is used to granulate the mixed slag to obtain granular mixed slag; A drying device, the drying device is used to dry the granular mixed slag to obtain dry particles; A roasting device, wherein the roasting device is used to perform a roasting and desulfurization treatment on the dried particles to obtain high-temperature roasted sand and roasting flue gas; A cooling device is used to cool the high-temperature roasted sand to obtain a crude iron roasted sand product.

12. The processing device according to claim 11, characterized in that It further comprises a heat exchange device, which is used to heat up the waste gas generated after the high-temperature roasted sand is cooled, and / or, the heat exchange device is used to cool down the waste gas generated after the roasting flue gas is subjected to secondary combustion.

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