Device and method for enriching impurity elements in smoke dust of tin smelting electric furnace

Abstract

The invention discloses a device and a method for enriching impurity elements in smoke dust of a tin smelting electric furnace. The enrichment device comprises a hopper, a feeding belt, an electric furnace, a re-combustion chamber, a surface cooling pipe, a cloth bag, an impurity removal belt and a wet impurity removal system which are connected in sequence. The enrichment method comprises the following steps: (1) mixing a tin-containing high-zinc material and a tin-containing high-cadmium material, loading the mixture into a hopper, and feeding the mixture into an electric furnace through a feeding belt for reduction smelting; (2) the flue gas enters a surface cooling pipe to be cooled after being subjected to secondary combustion and sedimentation in a recombustion chamber, and then flows through a cloth bag to be enriched; and (3) the high-zinc and high-cadmium smoke enters a wet impurity removal system through an impurity removal belt to be treated. By utilizing the advantages of high temperature in the electric furnace, short single-furnace smelting time, easiness in atmosphere control, high controllability of a dust collection process and the like, the zinc and cadmium enrichment wet feeding open circuit is realized, so that the influence of zinc and cadmium on a tin smelting system is reduced to the greatest extent, the long-period effective operation of the tin smelting system is realized, the sale creation effect of non-valued metals is activated, and the production cost is reduced. And the economic index of the tin smelting technology is improved.

Description

Technical Field

[0001] The invention relates to the technical field of nonferrous metallurgy, and more particularly to a device and a method for enriching impurity elements in tin smelting electric furnace dust. Background Art

[0002] Tin smelting raw materials contain certain impurities of zinc and cadmium. These impurity elements will circulate repeatedly in the main tin smelting furnaces and their dust collection systems, which will endanger the physical and mental health of employees and increase energy consumption. If the electric furnace is not used for enrichment, zinc and cadmium will continue to be enriched and increased in the furnace dust collection system, and there is a risk of blocking the dust collection system and causing a sudden stop in production, which directly affects the economic and technical indicators of tin smelting. Therefore, how to control the zinc and cadmium content in the furnace smoke, find the process conditions for enriching zinc and cadmium, and maximize the capture of zinc and cadmium into the wet system for processing is an important prerequisite for improving the technical and economic indicators and economic benefits of tin smelting, and it is also the most important assessment indicator for green tin smelting.

[0003] Therefore, how to enrich the impurity elements in the smoke from tin smelting electric furnaces is a problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a device and method for enriching impurity elements in tin smelting electric furnace smoke to solve the deficiencies in the prior art.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A device for enriching impurity elements in tin smelting electric furnace dust comprises a hopper, a feeding belt, an electric furnace, a re-burning chamber, a surface cooling tube, a cloth bag, a de-impurity belt and a wet de-impurity system which are connected in sequence.

[0007] Furthermore, the above-mentioned device for enriching impurity elements in the smoke of the tin smelting electric furnace also includes a tin chute and a front bed, and the electric furnace, the tin chute and the front bed are connected in sequence.

[0008] A further beneficial effect of the above method is that the mixture of crude tin and tin slag obtained after reduction smelting enters the front bed through the tin chute for precipitation separation, the obtained crude tin (mass percentage of tin ≥ 85%) enters the refining system, and the obtained tin slag (mass percentage of tin ≤ 6%) enters the fuming furnace to recover valuable metals.

[0009] Furthermore, the above-mentioned device for enriching impurity elements in the smoke of the tin smelting electric furnace also includes an electrode, and the electric furnace and the electrode are connected.

[0010] A further beneficial effect of adopting the above method is that the present invention can infer the progress of the reaction in the furnace according to the current and voltage of the electrode; it can also adjust the depth of the electrode to control the material reduction rate according to the reduction situation, and basically no safety and environmental risks such as material collapse and smoke will occur.

[0011] A method for enriching impurity elements in tin smelting electric furnace dust, using the above-mentioned device for enriching impurity elements in tin smelting electric furnace dust, specifically comprises the following steps:

[0012] (1) mixing a tin-containing high-zinc material and a tin-containing high-cadmium material and loading them into a hopper, and then feeding them into an electric furnace through a feeding belt for reduction smelting to obtain a mixture of crude tin and tin slag and flue gas;

[0013] (2) The flue gas is subjected to secondary combustion and settling in the afterburning chamber, and then enters the surface cooling tube for cooling, and then flows through the bag filter for enrichment to obtain high-zinc and high-cadmium smoke;

[0014] (3) The high-zinc and high-cadmium smoke is sent to the wet decontamination system through the decontamination belt for wet decontamination treatment, and valuable metals such as tin and lead are recovered while zinc and cadmium are enriched and sold out.

[0015] The present invention utilizes the advantages of high temperature in the electric furnace, short smelting time in a single furnace, easy atmosphere control, and high controllability of the dust collection process to enrich zinc and cadmium by wet-feeding method, thereby minimizing the influence of zinc and cadmium on the tin smelting system, achieving long-term effective operation of the tin smelting system, activating the external sale of non-priced metals, and improving the economic indicators of tin smelting technology.

[0016] Furthermore, the above-mentioned method for enriching impurity elements in tin smelting electric furnace smoke also includes: passing a mixture of crude tin and tin slag into a front bed through a tin chute, precipitating and separating, and the obtained crude tin (mass percentage of tin ≥85%) enters a refining system, and the obtained tin slag (mass percentage of tin ≤6%) enters a fuming furnace to recover valuable metals.

[0017] Furthermore, in the above step (1), in the tin-containing high-zinc material, the mass percentage of zinc is ≥8%, preferably 9.24%-10.51%; in the tin-containing high-cadmium material, the mass percentage of cadmium is ≥6%, preferably 7.64%-9.82%; during the reduction smelting process, limestone or quartz is added to a silicate acidity of 0.85-1.10, the temperature is 1450-1600°C, the current is 6200-7000A, and the time is ≥4.5h, until the mass percentage of tin in the tin slag is ≤6%.

[0018] Furthermore, in the above step (2), the temperature of the afterburning chamber is 750-1000°C.

[0019] The above further beneficial effect is that the temperature can meet the secondary combustion requirements of the flue gas entering the reburning chamber, and prevent the carbon monoxide and other impurities in the flue gas that are easy to burn from entering the bag and burning the bag. The smoke dust settled in the reburning chamber and after secondary combustion is returned to the electric furnace for reduction smelting to recover valuable metals.

[0020] Furthermore, in the above step (2), the inlet temperature of the cloth bag is 150-180°C.

[0021] A further beneficial effect of the above method is that the cooling pipe can be partially opened and stopped according to the temperature of the bag dust box inlet, and the inlet of the bag can be controlled at 150-180°C, which can prevent the bag from being burned by excessive temperature and from being corroded by moisture due to low temperature.

[0022] Furthermore, in the above step (2), when the sum of the mass percentages of zinc and cadmium in the high-zinc and high-cadmium smoke is ≥30%, the high-zinc and high-cadmium smoke is passed through a de-impurity belt into a wet de-impurity system for wet de-impurity treatment; when the sum of the mass percentages of zinc and cadmium in the high-zinc and high-cadmium smoke is <30%, granulation is performed again and the dust is returned to the electric furnace for reduction smelting.

[0023] Furthermore, in the above step (3), after the wet decontamination treatment, the zinc-cadmium carbonate slag with a tin mass percentage of ≤0.5% is dried and sold to achieve harmless treatment of impurities zinc and cadmium; the tin-containing raw material with a sum of the mass percentages of zinc and cadmium less than 1.2% is returned to the electric furnace for reduction smelting, thereby improving the economic indicators of tin smelting technology.

[0024] A further beneficial effect of adopting the above method is that a certain economic benefit is obtained while reducing the impact of zinc and cadmium on the tin smelting system.

[0025] It can be seen from the above technical solution that compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] 1. Low difficulty in management and control. Compared with other metallurgical furnaces, electric furnaces have the advantages of high furnace temperature, short single furnace smelting time, easy atmosphere control, and high controllability of dust collection process. At the same time, the present invention can infer the progress of the reaction in the furnace according to the current and voltage of the electrode, and then combine manual furnace exploration and opening observation to accurately judge the material reaction situation and adjustment conditions. It does not have strict requirements on the professional level of the operator, and the management and control difficulty is low.

[0027] (2) Good economic benefits. The zinc and cadmium recovered by the present invention are harmful impurities during tin smelting. They are purchased without price. After recovery, they are sold at a price based on grade, which has good economic benefits.

[0028] (3) Short process. The present invention adopts electric furnace enrichment, and the materials are directly put into the furnace for reduction after batching. The flue gas is captured and enters the acid making system after secondary combustion, sedimentation and cooling. The process is short and easy to clean.

[0029] (4) Low safety and environmental protection risks. The ball formation rate of the raw materials entering the furnace of the present invention reaches more than 88%, the gap in the reduction smelting process is large, the adjustment range of silica acidity is reasonable, and the depth of the electrode can be adjusted according to the reduction situation to control the material speed, and basically no safety and environmental protection risks such as collapse and smoke will occur. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0031] Figure 1 The present invention is a schematic structural diagram of a device for enriching impurity elements in tin smelting electric furnace dust.

[0032] Among them, 1- hopper, 2- feeding belt, 3- electric furnace, 4- tin chute, 5- front bed, 6- afterburning chamber, 7- surface cooling tube, 8- cloth bag, 9- impurity removal belt, 10- wet impurity removal system, 11- electrode. DETAILED DESCRIPTION

[0033] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0034] In the description of the present invention, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0035] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0036] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0038] Example 1

[0039] The device for enriching impurity elements in tin smelting electric furnace dust comprises a hopper 1, a feed belt 2, an electric furnace 3, a re-burning chamber 6, a surface cooling tube 7, a cloth bag 8, a de-impurity belt 9 and a wet de-impurity system 10 which are connected in sequence.

[0040] Example 2

[0041] The device for enriching impurity elements in tin smelting electric furnace dust comprises a hopper 1, a feeding belt 2, an electric furnace 3, a reburning chamber 6, a surface cooling tube 7, a cloth bag 8, a decontamination belt 9 and a wet decontamination system 10 which are connected in sequence;

[0042] It also includes a tin trough 4 and a front bed 5, and the electric furnace 3, the tin trough 4 and the front bed 5 are connected in sequence.

[0043] Example 3

[0044] The device for enriching impurity elements in tin smelting electric furnace dust comprises a hopper 1, a feeding belt 2, an electric furnace 3, a reburning chamber 6, a surface cooling tube 7, a cloth bag 8, a decontamination belt 9 and a wet decontamination system 10 which are connected in sequence;

[0045] It also includes a tin trough 4 and a front bed 5, and the electric furnace 3, the tin trough 4 and the front bed 5 are connected in sequence.

[0046] It also includes an electrode 11, and the electric furnace 3 is connected to the electrode 11.

[0047] Example 4

[0048] The method for enriching impurity elements in tin smelting electric furnace dust adopts the device for enriching impurity elements in tin smelting electric furnace dust of Example 3, and specifically comprises the following steps:

[0049] (1) mixing a tin-containing high-zinc material and a tin-containing high-cadmium material and loading them into a hopper 1, and then feeding them into an electric furnace 3 through a feeding belt 2 for reduction smelting to obtain a mixture of crude tin and tin slag and flue gas;

[0050] The mass percentage of zinc in the tin-containing high-zinc material is 9.54%; the mass percentage of cadmium in the tin-containing high-cadmium material is 7.88%; during the reduction smelting process, limestone is added to a silicate acidity of 0.86, the temperature is 1500° C., the current of electrode 11 is 6500A, and the time is 4.8 hours;

[0051] (2) The mixture of crude tin and tin slag enters the front bed 5 through the tin chute 4 for precipitation and separation. The obtained crude tin enters the refining system, and the obtained tin slag enters the fuming furnace to recover valuable metals;

[0052] (3) the flue gas is subjected to secondary combustion and settling in a 750° C. after-burning chamber 6, and then enters a surface cooling tube 7 for cooling, and then flows through a cloth bag 8 with an inlet temperature of 160° C. for enrichment, to obtain high-zinc and high-cadmium flue gas with a sum of the mass percentages of zinc and cadmium ≥ 30%; when the sum of the mass percentages of zinc and cadmium in the high-zinc and high-cadmium flue gas is less than 30%, granulation is performed again, and the flue gas is returned to the electric furnace 3 for reduction smelting;

[0053] (4) The high-zinc and high-cadmium smoke is sent to the wet decontamination system 10 through the decontamination belt 9 for wet decontamination treatment, and then the zinc-cadmium carbonate slag with a tin mass percentage of ≤0.5% is dried and sold, and the tin-containing raw material with a sum of the mass percentages of zinc and cadmium less than 1.2% is returned to the electric furnace 3 for reduction smelting.

[0054] Example 5

[0055] The method for enriching impurity elements in tin smelting electric furnace dust adopts the device for enriching impurity elements in tin smelting electric furnace dust of Example 3, and specifically comprises the following steps:

[0056] (1) mixing a tin-containing high-zinc material and a tin-containing high-cadmium material and loading them into a hopper 1, and then feeding them into an electric furnace 3 through a feeding belt 2 for reduction smelting to obtain a mixture of crude tin and tin slag and flue gas;

[0057] In the tin-containing high-zinc material, the mass percentage of zinc is 10.11%; in the tin-containing high-cadmium material, the mass percentage of cadmium is 8.88%; during the reduction smelting process, limestone is added until the silica acidity is 1.04, the temperature is 1550°C, the current of electrode 11 is 6500A, and the time is 4.8h;

[0058] (2) The mixture of crude tin and tin slag enters the front bed 5 through the tin chute 4 for precipitation and separation. The obtained crude tin enters the refining system, and the obtained tin slag enters the fuming furnace to recover valuable metals;

[0059] (3) the flue gas is subjected to secondary combustion and settling in a 750° C. after-burning chamber 6, and then enters a surface cooling tube 7 for cooling, and then flows through a cloth bag 8 with an inlet temperature of 160° C. for enrichment, to obtain high-zinc and high-cadmium flue gas with a sum of the mass percentages of zinc and cadmium ≥ 30%; when the sum of the mass percentages of zinc and cadmium in the high-zinc and high-cadmium flue gas is less than 30%, granulation is performed again, and the flue gas is returned to the electric furnace 3 for reduction smelting;

[0060] (4) The high-zinc and high-cadmium smoke is sent to the wet decontamination system 10 through the decontamination belt 9 for wet decontamination treatment, and then the zinc-cadmium carbonate slag with a tin mass percentage of ≤0.5% is dried and sold, and the tin-containing raw material with a sum of the mass percentages of zinc and cadmium less than 1.2% is returned to the electric furnace 3 for reduction smelting.

[0061] Comparative Example 1

[0062] The only difference from Example 4 is that the silica acidity of the reduction smelting is 0.83.

[0063] Comparative Example 2

[0064] The only difference from Example 5 is that the reduction smelting time is 4.5 h.

[0065] Performance Testing

[0066] The mass fraction of tin in the tin slag in step (2) of Examples 4-5 and Comparative Examples 1-2, and the sum of the mass percentages of zinc and cadmium in the high-zinc and high-cadmium smoke in step (3) were tested respectively.

[0067] The results are shown in Table 1.

[0068] Table 1 Performance test results of Examples 4-5 and Comparative Examples 1-2

[0069]

[0070] As shown in Table 1, in the tin slag of Examples 4-5, the mass fraction of tin is ≤6%, and the sum of the mass percentages of zinc and cadmium in the high-zinc and high-cadmium dust is ≥30.51%. In Comparative Examples 1-2, the mass fraction of tin is ≤7.5%, and the sum of the mass percentages of zinc and cadmium in the high-zinc and high-cadmium dust is ≥26.39%.

[0071] The above experiments show that the present invention, by utilizing the advantages of high temperature in the electric furnace, short smelting time in a single furnace, easy atmosphere control, and high controllability of the dust collection process, enriches zinc and cadmium by wet-feeding method, thereby minimizing the impact of zinc and cadmium on the tin smelting system, achieving long-term effective operation of the tin smelting system, activating the external sale of non-priced metals, and improving the economic indicators of tin smelting technology.

[0072] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.

[0073] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A device for enriching impurity elements in tin smelting electric furnace dust, characterized in that: The utility model comprises a hopper, a feeding belt, an electric furnace, a re-burning chamber, a surface cooling pipe, a cloth bag, a de-impurity belt and a wet de-impurity system which are connected in sequence.

2. The device for enriching impurity elements in tin smelting electric furnace dust according to claim 1, characterized in that: It also includes a tin trough and a front bed, and the electric furnace, the tin trough and the front bed are connected in sequence.

3. The device for enriching impurity elements in tin smelting electric furnace dust according to claim 1, characterized in that: It also includes an electrode, and the electric furnace is connected to the electrode.

4. A method for enriching impurity elements in tin smelting electric furnace dust, characterized in that: The device for enriching impurity elements in tin smelting electric furnace dust as claimed in any one of claims 1 to 3 specifically comprises the following steps: (1) mixing a tin-containing high-zinc material and a tin-containing high-cadmium material and loading them into a hopper, and then feeding them into an electric furnace through a feeding belt for reduction smelting to obtain a mixture of crude tin and tin slag and flue gas; (2) The flue gas is subjected to secondary combustion and settling in the afterburning chamber, and then enters the surface cooling tube for cooling, and then flows through the bag filter for enrichment to obtain high-zinc and high-cadmium smoke; (3) The high-zinc and high-cadmium smoke is sent to the wet decontamination system through a decontamination belt for wet decontamination treatment. While recovering valuable metals, zinc and cadmium are enriched and sold off.

5. The method for enriching impurity elements in tin smelting electric furnace dust according to claim 4, characterized in that: Also includes: The mixture of crude tin and tin slag enters the front bed through the tin chute for sedimentation and separation. The obtained crude tin enters the refining system, and the obtained tin slag enters the fuming furnace to recover valuable metals.

6. The method for enriching impurity elements in tin smelting electric furnace dust according to claim 4, characterized in that: In step (1), the mass percentage of zinc in the tin-containing high-zinc material is ≥8%; the mass percentage of cadmium in the tin-containing high-cadmium material is ≥6%; during the reduction smelting process, limestone or quartz is added to a silicate acidity of 0.85-1.10, the temperature is 1450-1600° C., the current is 6200-7000A, and the time is ≥4.5h, until the mass percentage of tin in the tin slag is ≤6%.

7. The method for enriching impurity elements in tin smelting electric furnace dust according to claim 4, characterized in that: In step (2), the temperature of the afterburning chamber is 750-1000°C.

8. The method for enriching impurity elements in tin smelting electric furnace dust according to claim 4, characterized in that: In step (2), the inlet temperature of the cloth bag is 150-180°C.

9. The method for enriching impurity elements in tin smelting electric furnace dust according to claim 4, characterized in that: In step (2), when the sum of the mass percentages of zinc and cadmium in the high-zinc and high-cadmium smoke is ≥30%, the high-zinc and high-cadmium smoke enters a wet de-impurity system through a de-impurity belt for wet de-impurity treatment; when the sum of the mass percentages of zinc and cadmium in the high-zinc and high-cadmium smoke is <30%, granulation is performed again and the smoke is returned to the electric furnace for reduction smelting.

10. The method for enriching impurity elements in tin smelting electric furnace dust according to claim 4, characterized in that: In step (3), after the wet decontamination treatment, the zinc-cadmium carbonate slag with a tin mass percentage of ≤0.5% is dried and sold, and the tin-containing raw material with a sum of the mass percentages of zinc and cadmium of <1.2% is returned to the electric furnace for reduction smelting.

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