Composite treatment process for high-temperature reduction and oxidation of smelting slag

Abstract

The invention discloses a composite treatment process for high-temperature reduction and oxidation of smelting slag, and belongs to the technical field of non-ferrous metal smelting. Comprising the following steps that smelting slag and fuel are added into a first smelting furnace for high-temperature reduction smelting, the temperature in the first smelting furnace is controlled to range from 1400 DEG C to 1500 DEG C, and a metal phase, iron-rich smelting slag and first smelting furnace smoke are obtained; the smelting slag rich in iron is fed into a second smelting furnace to be subjected to high-temperature oxidation smelting, the temperature in the second smelting furnace is controlled to be 1400-1600 DEG C, and foamed slag and second smelting furnace smoke are obtained; the foam slag is subjected to granulation treatment, cooling is conducted after treatment is completed, and smelting slag containing Fe3O4 is obtained; and after the Fe3O4-containing smelting slag is subjected to ore grinding and magnetic separation, iron ore concentrate and tailings are obtained. By means of the high-temperature phase splitting-slag phase oxidation-magnetic separation enrichment cooperative treatment technology, the problems that an existing smelting slag treatment process is complex, the environment is polluted, the valuable metal recovery rate is low, and the iron ore concentrate quality is low are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of nonferrous metal smelting, and in particular relates to a composite treatment process for smelting slag. Background Art

[0002] Copper smelting slag usually contains valuable metals such as copper (0.5%~3%), lead and zinc (0.1%~1.5%), and iron (35%~45%). Traditional copper smelting slag treatment methods mainly include slag beneficiation and slag electric furnace depletion. Among them, although the slag beneficiation process can recover copper, iron and other valuable metals from copper smelting slag and improve the comprehensive utilization rate of resources, this method has the following disadvantages: (1) Low recovery rate: The mineral composition of copper smelting slag is complex, and it is difficult to completely separate these minerals during the beneficiation process, resulting in insufficient recovery of valuable metals. (2) Limited magnetic separation accuracy: The iron oxide content of olivine (Fe2SiO4) in copper slag is high and its magnetic properties are weak, making it difficult to effectively recover it by magnetic separation. In addition, iron concentrate often contains impurities such as lead and zinc, and cannot be directly used as a raw material for steelmaking. (3) Poor adaptability to slag: The composition and properties of copper smelting slag vary greatly due to factors such as smelting process and raw material source. Changes in the copper grade, sulfur content, oxidation degree, etc. in the slag will affect the mineral processing indicators. (4) Tailings treatment is difficult: mineral processing tailings cannot be used directly in the construction industry and still need to be stored in open-air piles. Toxic elements such as lead and arsenic remaining in the tailings may be released during weathering and rainwater erosion, leading to environmental problems such as soil salinization and groundwater pollution. Among them, the slag electric furnace depletion process does not require large crushing, grinding, flotation and other equipment and corresponding factory buildings and yards compared to the slag mineral processing process, and has the advantage of a small footprint. However, the recovery rate of valuable metals in this process is still not very high. The copper content in the depleted slag is high, and some heavy metals or harmful elements (such as lead, arsenic, etc.) may remain. In addition, this process has the problem of high energy consumption. Its electricity consumption is large and it relies on a stable power supply.

[0003] Chinese patent application number 202011580185.X discloses a method for separating and recovering valuable metals by chlorination roasting of copper smelting slag. While this method achieves efficient separation of lead, zinc, and iron through staged temperature increase, atmosphere control, and magnetic separation, it requires strict staged temperature control (a first stage of 800-850°C, a second stage of 1000-1050°C) and precise atmosphere adjustment, requiring high operational skills. Furthermore, the chlorination roasting process may generate chlorine gas, placing high demands on equipment materials and sealing properties. Chlorine gas handling is complex and poses certain environmental risks.

[0004] Chinese patent application number 202210274701.9 discloses a copper smelting slag dilution smelting process. This method primarily utilizes an oxygen-enriched, side-blown, dual-zone molten pool smelting method to dilute the copper smelting slag. However, this process is difficult to coordinate and control the dual-zone furnaces, has poor adaptability to raw materials, and requires strict control over slag composition. Summary of the Invention

[0005] The main purpose of the present invention is to provide a composite treatment process for high-temperature reduction and oxidation of smelting slag. Through a high-temperature phase separation-slag phase oxidation-magnetic separation enrichment coordinated treatment technology, and coordinated control of temperature and oxidizing atmosphere, the volatilization of lead, zinc, arsenic and silver and the reconstruction of the iron phase are achieved, thereby solving the technical problems of the existing technology such as complex treatment process, environmental pollution, low recovery rate of valuable metals, and low quality of iron concentrate.

[0006] In order to achieve the above object, the present invention provides a composite treatment process of high-temperature reduction and oxidation of smelting slag, comprising the following steps: adding smelting slag and fuel into a first smelting furnace for high-temperature reduction smelting, controlling the temperature in the first smelting furnace to be 1400° C. to 1500° C., to obtain a metallic phase, iron-rich smelting slag, and first smelting furnace flue gas; feeding the iron-rich smelting slag into a second smelting furnace for high-temperature oxidation smelting, controlling the temperature in the second smelting furnace to be 1400° C. to 1600° C., to obtain foamed slag and second smelting furnace flue gas; The foamed slag is granulated and cooled after the treatment to obtain Fe3O4-containing smelting slag; The Fe3O4-containing smelting slag is subjected to grinding and magnetic separation to obtain iron concentrate and tailings.

[0007] Furthermore, the second smelting furnace contains an oxygen-rich atmosphere, and the oxygen volume concentration of the oxygen-rich atmosphere is 21-95%.

[0008] Furthermore, the mass ratio of the smelting slag to the fuel is 1:0.01~0.1.

[0009] Furthermore, the fuel is selected from one or more of pulverized coal, lump coal or natural gas.

[0010] Furthermore, the oxygen consumption during the high temperature oxidation smelting process is 15-25 Nm / t of the weight of the iron-rich smelting slag. 3 .

[0011] Furthermore, the granulation treatment is selected from wet granulation or dry granulation; wherein the wet granulation is water quenching and the water pressure of the water quenching and the wind speed is 10~30Nm 3 / s; the dry granulation is wind-broken, the wind pressure of the wind-broken is 0.2~1.0MPa, and the wind speed is higher than 150Nm 3 / s.

[0012] Furthermore, the composite treatment process further comprises the following steps: passing the flue gas from the first smelting furnace and the flue gas from the second smelting furnace into a waste heat boiler to recover waste heat, thereby obtaining first smoke dust and first flue gas; performing dust collection treatment on the first flue gas to obtain second flue dust and second flue gas; After the first smoke dust and the second smoke dust are subjected to wet treatment, valuable metals such as lead, zinc, arsenic and silver are recovered.

[0013] Furthermore, the second smelting furnace adopts the following structural design, including a furnace body, a blowing device and a transmission device, the transmission device is arranged at both ends of the furnace body, for realizing the rotation of the furnace body; the blowing device is arranged below the furnace body, for blowing oxygen-rich atmosphere into the furnace body; the furnace body includes a furnace shell and a refractory lining, the furnace shell adopts a composite configuration of a cylindrical bottom and a square furnace mouth, the feed port of the furnace body is a top square furnace mouth, and the slag discharge port of the furnace body is arranged at the end of the furnace body.

[0014] Furthermore, the first smelting furnace is selected from a side-blown furnace or a bottom-blown furnace.

[0015] Furthermore, the smelting slag is selected from one or more of copper smelting slag, nickel smelting slag and lead smelting slag.

[0016] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention precisely controls the temperature of high-temperature reduction smelting, allowing volatile metals such as lead, zinc, arsenic, and silver contained in the smelting slag to enter the flue gas of the first smelting furnace. Medium-melting-temperature metals such as copper and nickel contained in the smelting slag are melted and enriched in the bottom layer to form a metallic phase, and iron in the smelting slag is enriched in the smelting slag. By utilizing the volatility and melting characteristics of each metal, effective separation between metals is achieved, the recovery rate of various valuable metals is improved, and the efficient utilization of valuable metals is achieved, reducing the burden of tailings treatment.

[0017] (2) The present invention precisely controls the temperature and oxidizing atmosphere of high-temperature oxidation smelting, and oxidizes the metallic Fe and iron-containing compounds such as FeO and Fe2SiO4 in the iron-rich smelting slag to generate ferroferric oxide, thereby increasing the magnetic properties and facilitating subsequent magnetic separation. At the same time, it reduces the lead and zinc content in the iron concentrate and improves the quality of the iron concentrate. The tailings after magnetic separation can be used as the raw material for silicon powder products, and the silicon content of the raw material is high in purity.

[0018] (3) The present invention achieves energy saving and consumption reduction through the design of cascade utilization of thermal energy. In the reaction system of the second smelting furnace, the strong exothermic property of FeO oxidation to generate Fe3O4 is utilized to construct a self-heating system, thereby reducing the demand for external heating and improving energy utilization efficiency.

[0019] (4) The high-temperature oxygen reduction and oxidation composite treatment process of the present invention reduces environmental pollution and has high adaptability to slag, and is suitable for treating iron-containing slag types such as copper smelting slag, nickel smelting slag, and lead smelting slag. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic flow chart of the composite treatment process of high-temperature reduction and oxidation of smelting slag according to the present invention is shown; Figure 2 A schematic side view of the structure of a second smelting furnace in an embodiment of the present invention is shown; Figure 3 A schematic diagram of the internal structure of a second smelting furnace in an embodiment of the present invention is shown; Among them, the above drawings include the following figure marks: 1. furnace body, 2. blowing device, 3. transmission device, 11. furnace shell, 12. refractory lining, 13. feed port, 14. slag outlet. DETAILED DESCRIPTION

[0021] It should be noted that, in the case of no conflict, the embodiments in this application and the features in the embodiments can be combined with each other. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope. The present invention will be described in detail below in conjunction with the embodiments.

[0022] To achieve the above objectives, an embodiment of the present invention provides a composite treatment process for high-temperature reduction and oxidation of smelting slag, comprising the following steps: adding smelting slag and fuel into a first smelting furnace for high-temperature reduction smelting, controlling the temperature in the first smelting furnace to be 1400° C. to 1500° C., to obtain a metallic phase, iron-rich smelting slag, and first smelting furnace flue gas; feeding the iron-rich smelting slag into a second smelting furnace for high-temperature oxidation smelting, controlling the temperature in the second smelting furnace to be 1400° C. to 1600° C., to obtain foamed slag and second smelting furnace flue gas; The foamed slag is granulated and cooled after the treatment to obtain Fe3O4-containing smelting slag; The Fe3O4-containing smelting slag is subjected to grinding and magnetic separation to obtain iron concentrate and tailings.

[0023] The present invention controls the high-temperature reduction smelting temperature at 1400°C to 1500°C, resulting in selective metal volatilization. This temperature suppresses the oxidation of iron in the smelting slag, allowing the melting of medium-melting-temperature metals such as copper and nickel, thereby enriching copper and nickel (with a recovery rate exceeding 95%). Meanwhile, metals such as lead, zinc, arsenic, and silver are volatilized and concentrated in the flue gas of the first smelting furnace. At this temperature, the residual lead and zinc content is significantly reduced to below 0.05%, while iron is concentrated in the smelting slag. This high-temperature intensification process achieves efficient removal of impurity metals and targeted enrichment of the target metal by optimizing thermodynamic conditions.

[0024] The present invention controls the high-temperature oxidation smelting temperature between 1400°C and 1600°C, which increases the oxidation rate of ferrous oxide in materials such as fayalite (2FeO·SiO2), making it more easily oxidized to form ferrosoferric oxide (Fe3O4). Temperatures below 1400°C result in incomplete oxidation of the ferrous oxide, leaving residual FeO. Temperatures above 1600°C may further oxidize Fe3O4 to Fe2O3, reducing product purity. Furthermore, maintaining the appropriate viscosity and fluidity of the slag within this temperature range facilitates the formation of foamy slag and ensures a thorough oxidation reaction.

[0025] In some optional embodiments of the present invention, the smelting slag can be selected from iron-containing slag types such as copper smelting slag, nickel smelting slag, and lead smelting slag. The residual metal content in copper smelting slag includes copper (0.5%-3%), lead and zinc (0.1%-1.5%), and iron (35%-45%). The residual metal content in nickel smelting slag includes nickel (0.2%-1.0%), copper (0.3%-1.0%), lead and zinc (0.1%-0.5%), and iron (40%-45%). The residual metal content in lead smelting slag includes lead (0.5%-5%), zinc (3.0%-15.0%), copper (0.2%-2.5%), and iron (20%-35%).

[0026] In a preferred embodiment of the present invention, the second smelting furnace contains an oxygen-enriched atmosphere, wherein the oxygen concentration of the oxygen-enriched atmosphere is 21% to 95% by volume. Oxygen has combustion-supporting properties and serves as both a combustion aid and an oxidant in the second smelting furnace. Controlling the oxygen concentration within the above range allows the metallic Fe and iron-containing compounds such as FeO and Fe2SiO4 in the iron-rich smelting slag to be fully oxidized into ferrosoferric oxide, thereby increasing the Fe3O4 conversion rate and facilitating subsequent magnetic separation. Further preferably, the oxygen concentration of the oxygen-enriched atmosphere is 60% to 80% by volume.

[0027] In order to further optimize the reduction efficiency of the high-temperature reduction smelting in the first smelting furnace and enhance the metal recovery rate, in a preferred embodiment of the present invention, the mass ratio of the smelting slag to the fuel is 1:0.01~0.1.

[0028] In an optional embodiment of the present invention, the fuel is selected from one or more of pulverized coal, lump coal or natural gas.

[0029] In order to further improve the conversion rate of Fe3O4 in the iron-rich smelting slag, in a preferred embodiment of the present invention, the oxygen consumption in the high-temperature oxidation smelting process is 15-25 Nm 3 .

[0030] In some preferred embodiments of the present invention, the granulation treatment is selected from wet granulation and dry granulation; wherein, the wet granulation is water quenching and breaking up (using a high-pressure water jet to impact the foam slag, and the instantaneous thermal stress generated by water quenching causes the foam slag to be mechanically broken, and rapid cooling and solidification are achieved). The dry granulation is wind breaking and breaking up (using a high-speed airflow to impact the foam slag, and the pneumatic impact generated by the airflow causes the foam slag to break into fine droplets, and then the physical heat of the foam slag is recovered). Furthermore, in order to improve the granulation efficiency and facilitate subsequent magnetic separation and grinding, and improve the resource recovery rate, the water pressure of the water quenching and breaking up is 0.2~1.0MPa, and the wind speed is 10~30Nm 3 / s. The dry granulation is wind-broken, and the wind pressure of the wind-broken is 0.2~1.0MPa, and the wind speed is higher than 150Nm 3 The particle size of the foamed slag after the granulation treatment is 0.5-10.0 mm.

[0031] In a preferred embodiment of the present invention, the composite treatment process further comprises the following steps: After the flue gas from the first smelting furnace and the flue gas from the second smelting furnace are introduced into a waste heat boiler to recover waste heat, first smoke dust and first flue gas are obtained; performing dust collection treatment on the first flue gas to obtain second flue dust and second flue gas; After the first smoke dust and the second smoke dust are subjected to wet treatment, valuable metals such as lead, zinc, arsenic and silver are recovered.

[0032] The present invention recovers valuable metals such as lead, zinc, arsenic, and silver by subjecting the flue gas from the first and second smelting furnaces to a flue gas treatment process that includes waste heat recovery, dust collection, and wet treatment (contaminated acid recovery). The treatment process achieves a recovery rate of over 90% for these valuable metals.

[0033] In an optional embodiment of the present invention, the second smelting furnace can adopt a bottom-blown furnace, a side-blown furnace, a top-blown furnace, a bottom-blown furnace and other furnace types. However, in order to better apply the treatment process of the present invention, the present invention specially designs the structure of the second smelting furnace, including a furnace body, a blowing device and a transmission device. The transmission device is arranged at both ends of the furnace body to realize the rotation of the furnace body, balance the temperature distribution in the furnace, and reduce local overheating or erosion; the blowing device is arranged below the furnace body to blow oxygen-rich atmosphere into the furnace body to control the concentration of the oxidizing atmosphere in the furnace; the furnace body includes a furnace shell and a refractory lining. The furnace shell adopts a composite configuration of a cylindrical bottom and a square furnace mouth. The feed port of the furnace body is a top square furnace mouth, and the slag outlet of the furnace body is arranged at the end of the furnace body.

[0034] Further preferably, the second smelting furnace has a diameter of 5-6 meters and a length of 10-12 meters. The refractory lining can be constructed of high-quality magnesia-chrome bricks to resist erosion by high-temperature melts and chemical corrosion, extending the life of the furnace. The injection device includes an oxygen lance constructed as a multi-layered casing. The inner tube carries oxygen for the smelting reaction, while the outer tube carries air for cooling and protection. The oxygen lance is self-consumable and requires replacement when the front section corrodes or burns to a certain length.

[0035] The design of the second smelting furnace of the present invention ensures the stability of the furnace, realizes uniform heating, avoids high viscosity of the smelting slag, ensures the fluidity of the slag, and facilitates material feeding. It also fully considers the diversity of the oxygen concentration filled. This flexibility enables the furnace to select the most appropriate oxygen concentration for combustion according to different production needs and economic considerations.

[0036] In a preferred embodiment of the present invention, in order to ensure that oxygen fully participates in the reaction and optimizes the high-temperature oxidation smelting effect, the oxygen injection lance is accurately inserted into the foamed slag layer in the furnace, and its end is controlled to be 2 to 3 meters away from the liquid surface.

[0037] In an optional embodiment of the present invention, the first smelting furnace may be selected from, for example, a side-blown furnace or a bottom-blown furnace.

[0038] The present application is further described in detail below with reference to specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in this application.

[0039] Example 1 A composite treatment process of high temperature reduction and oxidation of smelting slag, such as Figure 1 As shown, the following steps are included: (1) Copper-containing smelting slag (its main element chemical composition is: Cu: 1.8%, Pb: 0.57%, Zn: 2.5%, Fe: 42.98%, S: 0.75%) and fuel (lump coal) with a mass ratio of 1:0.05 are added to the first smelting furnace (side-blown furnace), and oxygen as a combustion agent is supplied to the furnace. The temperature in the furnace is controlled at 1450℃, and high-temperature reduction smelting is carried out for 1.5~2h. During this process, 99% of the copper is melted and separated, 95% of volatile metals such as lead, zinc, arsenic and silver enter the flue gas, and iron enters the smelting slag, resulting in a copper-rich metal phase, iron-rich smelting slag and the flue gas of the first smelting furnace.

[0040] (2) The iron-rich smelting slag is fed into the second smelting furnace (bottom-blown furnace), and oxygen-enriched air (oxygen volume concentration is 95%, and the oxygen consumption in the high-temperature oxidation smelting process is 22.4 Nm per ton of the iron-rich smelting slag) is blown into the furnace. 3 ) to carry out high-temperature oxidation smelting, controlling the temperature in the furnace at 1450℃, and oxidizing the metal Fe, FeO, ferrous oxides in fayalite and other substances in the smelting slag to produce ferrosoferric oxide (Fe3O4), forming foamy slag and flue gas from the second smelting furnace.

[0041] (3) The foam slag overflows from the foam slag outlet, and is wet granulated after overflowing. The foam slag is broken up by water quenching (water pressure is 0.5MPa, wind speed is 20Nm 3 / s, the particle size of the foam slag after breaking up is 0.5~10.0mm), and then it is sent to the slag slow cooling field for cooling to obtain Fe3O4-containing smelting slag.

[0042] (4) The Fe3O4-containing smelting slag was ground and then magnetically separated from the smelting slag using a magnetic separation device (magnetic separation intensity of 0.8T) to obtain iron concentrate. The iron concentrate grade after magnetic separation was approximately 83%, and the iron recovery rate was approximately 86%.

[0043] (5) The flue gas from the first smelting furnace and the flue gas from the second smelting furnace are introduced into a waste heat boiler to recover waste heat, thereby obtaining first smoke dust and first flue gas.

[0044] (6) The first flue gas is subjected to dust collection treatment (electrostatic precipitator dust collection, bag dust collection) to obtain second flue dust and second flue gas, and the first flue dust and the second flue dust are subjected to dirty acid treatment to recover Zn and As (recovery rate reaches 99%), and further recovered to obtain lead paste (recovery rate reaches 99%); the second flue gas is subjected to tail gas treatment (desulfurization).

[0045] Example 2 A composite treatment process of high temperature reduction and oxidation of smelting slag, such as Figure 1 As shown, the following steps are included: (1) Nickel-containing smelting slag (its main element chemical composition is: Ni: 0.3%, Pb: 0.5%, Zn: 2.3%, Fe: 30%, S: 0.8%) and fuel (lump coal) with a mass ratio of 1:0.1 are added to the first smelting furnace (side-blown furnace), and oxygen as a combustion agent is supplied to the furnace. The temperature in the furnace is controlled at 1430℃, and high-temperature reduction smelting is carried out for 1.5~2h. During this process, 97% of the nickel is melted and separated, 95% of volatile metals such as lead, zinc, arsenic and silver enter the flue gas, and iron enters the smelting slag, resulting in a nickel-rich metal phase, iron-rich smelting slag and the flue gas of the first smelting furnace.

[0046] (2) The iron-rich smelting slag is fed into the second smelting furnace (bottom-blown furnace), and oxygen-enriched air is blown into the furnace (the volume concentration of oxygen is 80%, and the oxygen consumption in the high-temperature oxidation smelting process is 24Nm3 per ton of the weight of the iron-rich smelting slag). 3 ) to carry out high-temperature oxidation smelting, controlling the temperature in the furnace at 1450℃, and oxidizing the metal Fe, FeO, ferrous oxides in fayalite and other substances in the smelting slag to produce ferrosoferric oxide (Fe3O4) to form foamy slag and flue gas from the second smelting furnace.

[0047] (3) The foam slag overflows from the foam slag outlet and is broken up by wind (wind pressure is 0.5MPa, wind speed is 160Nm 3 / s, the particle size of the foam slag after breaking up is 0.5~10.0mm), and then it is sent to the slag slow cooling field for cooling to obtain Fe3O4-containing smelting slag.

[0048] (4) The Fe3O4-containing smelting slag is ground and then magnetically separated from the smelting slag using a magnetic separation device (magnetic separation intensity of 0.8T) to obtain iron concentrate. The iron concentrate grade after magnetic separation is approximately 80% or more, and the iron recovery rate is approximately 86%.

[0049] (5) The flue gas from the first smelting furnace and the flue gas from the second smelting furnace are introduced into a waste heat boiler to recover waste heat, thereby obtaining first smoke dust and first flue gas.

[0050] (6) The first flue gas is subjected to dust collection treatment (electrostatic precipitator dust collection, bag dust collection) to obtain second flue dust and second flue gas, the first flue dust and the second flue dust are subjected to dirty acid treatment to recover Zn and As, and further recovered to obtain lead paste (containing lead); the second flue gas is subjected to tail gas treatment (desulfurization).

[0051] Example 3 A composite treatment process of high temperature reduction and oxidation of smelting slag, such as Figure 1 As shown, the following steps are included: (1) Zinc-containing smelting slag (its main element chemical composition is: Zn: 2.5%, Pb: 1.2%, Cu: 1.0%, Fe: 28%) and fuel (lump coal) with a mass ratio of 1:0.08 are added to the first smelting furnace (side-blown furnace), and oxygen as a combustion agent is supplied to the furnace. The temperature in the furnace is controlled at 1400℃, and high-temperature reduction smelting is carried out for 1.5~2h. During this process, 98% of the copper is melted and separated, 95% of the volatile metals such as lead, zinc, arsenic and silver enter the flue gas, and iron enters the smelting slag, resulting in a copper-rich metal phase, iron-rich smelting slag and the flue gas of the first smelting furnace.

[0052] (2) The iron-rich smelting slag is fed into the second smelting furnace (bottom-blown furnace), and oxygen-enriched air is blown into the furnace (the volume concentration of oxygen is 75%, and the oxygen consumption in the high-temperature oxidation smelting process is 23Nm per ton of the weight of the iron-rich smelting slag). 3 ) to carry out high-temperature oxidation smelting, controlling the temperature in the furnace at 1400°C to form foamy slag and flue gas from the second smelting furnace.

[0053] (3) The foam slag overflows from the foam slag outlet and is broken up by wind (wind pressure is 0.5MPa, wind speed is 160Nm 3 / s, the particle size of the foam slag after breaking up is 0.5~10.0mm), and then it is sent to the slag slow cooling field for cooling to obtain Fe3O4-containing smelting slag.

[0054] (4) The Fe3O4-containing smelting slag is ground and then magnetically separated from the smelting slag using a magnetic separation device (magnetic separation intensity of 0.8T) to obtain iron concentrate. The iron concentrate grade after magnetic separation is approximately 83% or above, and the iron recovery rate is approximately 85%.

[0055] (5) The flue gas from the first smelting furnace and the flue gas from the second smelting furnace are introduced into a waste heat boiler to recover waste heat, thereby obtaining first smoke dust and first flue gas.

[0056] (6) The first flue gas is subjected to dust collection treatment (electrostatic precipitator dust collection, bag dust collection) to obtain second flue dust and second flue gas, the first flue dust and the second flue dust are subjected to dirty acid treatment to recover Zn and As, and further recovered to obtain lead paste (containing lead); the second flue gas is subjected to tail gas treatment (desulfurization).

[0057] Example 4 A composite treatment process for high-temperature reduction and oxidation of smelting slag, which differs from Example 1 in that the bottom-blowing furnace of the prior art used in the second smelting furnace of Example 1 is replaced by a specially designed second smelting furnace of the present invention, and its specific structure is as follows Figure 2 and Figure 3As shown, it includes a furnace body 1, a blowing device 2 and a transmission device 3, the transmission device 3 is arranged at both ends of the furnace body 1, and is used to realize the rotation of the furnace body 1, balance the temperature distribution in the furnace, and reduce local overheating or erosion; the blowing device 2 is arranged below the furnace body 1, and is used to blow oxygen-rich atmosphere into the furnace body to control the concentration of the oxidizing atmosphere in the furnace; the furnace body 1 includes a furnace shell 11 and a refractory lining 12, the furnace shell 11 adopts a composite configuration of a cylindrical bottom and a square furnace mouth, the feed port 13 of the furnace body 1 is a top square furnace mouth, and the slag outlet 14 of the furnace body is arranged at the end of the furnace body.

[0058] The final iron ore concentrate obtained from this treatment has a grade of approximately 86% and an iron recovery rate of approximately 90%.

[0059] Comparative Example 1 A combined high-temperature reduction and oxidation treatment process for smelting slag, differing from Example 1 in that the high-temperature reduction smelting temperature is 1300°C, and the high-temperature oxidation smelting temperature is 1300°C. The resulting iron concentrate has a grade of approximately 45% and an iron recovery rate of approximately 55%.

[0060] Comparative Example 2 A combined high-temperature reduction and oxidation treatment process for smelting slag, differing from Example 1 in that the high-temperature reduction smelting temperature is 1600°C and the high-temperature oxidation smelting temperature is 1700°C. The resulting iron concentrate has a grade of approximately 55% and an iron recovery rate of approximately 65%.

[0061] The embodiments described above are merely illustrative of embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. The present invention may also be implemented in other specific ways or in other specific forms without departing from the gist or essential features of the present invention. Therefore, the embodiments described should be considered in all respects as illustrative and not restrictive. The scope of the present invention should be described by the appended claims, and any variations equivalent to the intent and scope of the claims should also be included within the scope of the present invention.

Claims

1. A composite treatment process of high-temperature reduction and oxidation of smelting slag, characterized in that: The following steps are involved: adding smelting slag and fuel into a first smelting furnace for high-temperature reduction smelting, controlling the temperature in the first smelting furnace to be 1400° C. to 1500° C., to obtain a metallic phase, iron-rich smelting slag, and first smelting furnace flue gas; feeding the iron-rich smelting slag into a second smelting furnace for high-temperature oxidation smelting, controlling the temperature in the second smelting furnace to be 1400° C. to 1600° C., to obtain foamed slag and second smelting furnace flue gas; The foamed slag is granulated and cooled after the treatment to obtain Fe3O4-containing smelting slag; The Fe3O4-containing smelting slag is subjected to grinding and magnetic separation to obtain iron concentrate and tailings.

2. The composite treatment process of high-temperature reduction and oxidation of smelting slag according to claim 1, characterized in that: The second smelting furnace contains an oxygen-rich atmosphere, and the oxygen volume concentration of the oxygen-rich atmosphere is 21-95%.

3. The composite treatment process of high-temperature reduction and oxidation of smelting slag according to claim 1, characterized in that: The mass ratio of the smelting slag to the fuel is 1:0.01-0.

1.

4. The composite treatment process of high-temperature reduction and oxidation of smelting slag according to claim 1, characterized in that: The fuel is selected from one or more of pulverized coal, lump coal or natural gas.

5. The combined treatment process of high-temperature reduction and oxidation of smelting slag according to claim 1, characterized in that: The oxygen consumption during the high temperature oxidation smelting process is 15-25 Nm / ton of the weight of the iron-rich smelting slag. 3 .

6. The combined treatment process of high-temperature reduction and oxidation of smelting slag according to claim 1, characterized in that: The granulation process is selected from wet granulation or dry granulation; The wet granulation is water quenching, the water pressure of the water quenching is 0.2~1.0MPa, the wind speed is 10~30Nm 3 / s; The dry granulation is wind-broken, and the wind pressure of the wind-broken is 0.2-1.0 MPa and the wind speed is higher than 150 Nm 3 / s.

7. The combined treatment process of high-temperature reduction and oxidation of smelting slag according to claim 1, characterized in that: The composite treatment process further comprises the following steps: After the flue gas from the first smelting furnace and the flue gas from the second smelting furnace are introduced into a waste heat boiler to recover waste heat, first smoke dust and first flue gas are obtained; performing dust collection treatment on the first flue gas to obtain second flue dust and second flue gas; After the first smoke dust and the second smoke dust are subjected to wet treatment, valuable metals such as lead, zinc, arsenic and silver are recovered.

8. The combined treatment process of high-temperature reduction and oxidation of smelting slag according to claim 1, characterized in that: The second smelting furnace adopts the following structural design, including a furnace body, a blowing device and a transmission device. The transmission device is arranged at both ends of the furnace body for realizing the rotation of the furnace body; the blowing device is arranged below the furnace body for blowing an oxygen-rich atmosphere into the furnace body; the furnace body includes a furnace shell and a refractory lining. The furnace shell adopts a composite configuration of a cylindrical bottom and a square furnace mouth. The feed port of the furnace body is a top square furnace mouth, and the slag discharge port of the furnace body is arranged at the end of the furnace body.

9. The combined treatment process of high-temperature reduction and oxidation of smelting slag according to claim 1, characterized in that: The first smelting furnace is selected from a side-blown furnace or a bottom-blown furnace.

10. The combined treatment process of high-temperature reduction and oxidation of smelting slag according to claim 1, characterized in that: The smelting slag is selected from one or more of copper smelting slag, nickel smelting slag and lead smelting slag.

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