Process for treating high-lead bismuth oxidizing slag through oxygen-enriched side-blown converter

Abstract

The invention relates to a non-ferrous metal smelting technology, in particular to a process for treating high-lead-bismuth oxidizing slag through an oxygen-enriched side-blown converter, and provides a new path for treating the high-lead-bismuth oxidizing slag with large treatment capacity and low energy consumption. The reduction time and the reduction energy consumption are greatly reduced through rapid and efficient reduction smelting in oxygen-enriched side-blown converter equipment, and the lead and bismuth are partially separated in the reduction stage, so that the chlorination lead removal time is shortened. Converter reduction smelting treatment of the silver-bismuth-containing lead oxidizing slag is converted into oxygen-enriched side-blown converter treatment, so that the output rate of crude bismuth and crude silver can be greatly increased, and consumption of natural gas, oxygen and power is reduced. Through combustion and stirring of natural gas and rich oxygen in the side-blown furnace, the heat conduction and chemical reaction speed is increased. The reaction time is saved by 70%, and the processing cost is saved by about 60%. The reaction process has the function of preliminarily separating lead and bismuth, and qualified crude bismuth products can be produced after gold and silver are separated through a vacuum furnace. And the workload of removing lead, arsenic, antimony, tellurium and silver in the subsequent refining process is greatly reduced.

Description

TECHNICAL FIELD

[0001] The application relates to a non-ferrous smelting technology, in particular to a process for treating high-lead bismuth oxidized slag in an oxygen-rich side-blown furnace. BACKGROUND

[0002] The traditional treatment process of bismuth-lead oxidized slag in a silver separation furnace is as follows:

[0003] 1. static reduction smelting in a converter - bismuth-lead alloy melt separation copper removal;

[0004] 2. multi-stage distillation silver-gold separation in a vacuum furnace - bismuth-lead alloy chlorination refining lead and bismuth separation;

[0005] 3. arsenic and antimony removal by oxidation;

[0006] 4. tellurium removal by adding alkali;

[0007] 5. silver removal by adding zinc;

[0008] 6. zinc removal by chlorination;

[0009] 7. high-temperature refining;

[0010] 8. ingot casting.

[0011] The operation cycle is long, and the energy consumption is high. The main problem is that the reduction smelting time is long, the time length of each furnace is 12-24 hours, and the chlorination lead removal time is long, usually taking 24-96 hours. SUMMARY

[0012] The application aims to provide a process for treating high-lead bismuth oxidized slag in an oxygen-rich side-blown furnace to solve the problems in the background technology.

[0013] To achieve the above-mentioned purpose, the application provides the following technical scheme:

[0014] A process for treating high-lead bismuth oxidized slag in an oxygen-rich side-blown furnace, comprising the following steps:

[0015] Step one, silver separation by fire method, high-silver precious lead is produced by silver separation by fire method, and the produced high-silver lead bismuth oxidized slag is crushed and uniformly fed into the oxygen-rich side-blown furnace through a metering belt at a uniform speed to be fed into the oxygen-rich side-blown furnace for reduction smelting;

[0016] Step two, reduction smelting, a reducing agent is added during smelting to partially reduce the molten compound, part of the lead is separated, and ash, low-bismuth high-lead reduction slag and bismuth-lead alloy are produced; wherein the ash and low-bismuth high-lead reduction slag return lead system recovers lead and antimony, and the reducing agent is reducing coal;

[0017] The smelting process also adds sodium salt slag to reduce the melting point of the slag, improve its fluidity, and promote the separation of metal precipitation and slag; the sodium salt slag is conveyed together with the reducing coal and the crushed silver-containing high-lead bismuth oxide slag through a metering belt;

[0018] Step three, copper removal by liquation, the bismuth-lead alloy produced by reduction smelting is transferred to a copper removal by liquation pot to separate copper;

[0019] Step four, bismuth-silver separation, after copper removal, the low-copper bismuth-lead alloy is subjected to two-stage vacuum distillation in a vacuum furnace to obtain low-silver crude bismuth and high-silver lead-bismuth residue, and the efficient separation of bismuth and silver is completed; wherein, the crude bismuth alloy is used for direct sales or chlorination refining by using a traditional process;

[0020] Step five, silver production, the high-silver lead-bismuth residue is returned to the silver separation furnace for oxidation refining to separate lead and bismuth, and to produce crude silver.

[0021] The process for treating high-lead bismuth oxide slag in the oxygen-enriched side-blown furnace as described above: in the step one, the lead content in the produced silver-containing high-lead bismuth oxide slag is < 35%, and the mass ratio of lead to bismuth ranges from 0 to 0.8.

[0022] The process for treating high-lead bismuth oxide slag in the oxygen-enriched side-blown furnace as described above: in the step two, the reducing coal for limited reduction reaction in the smelting process uses natural gas as fuel supplemented with 90%-96% pure oxygen, and the gas stream is injected through a high-pressure combustion nozzle to forcibly stir the molten body in the furnace, thereby strengthening the reaction process and reaction rate; the added reducing coal is anthracite particle, and the addition ratio is 2%-6% of the dry weight of the bismuth slag; the limited reduction is performed on the silver-containing high-lead bismuth oxide to preliminarily separate lead and reduce the lead content of the high-silver bismuth-lead alloy.

[0023] The process for treating high-lead bismuth oxide slag in the oxygen-enriched side-blown furnace as described above: the carbon content in the anthracite particle is greater than 80%.

[0024] The process for treating high-lead bismuth oxide slag in the oxygen-enriched side-blown furnace as described above: in the step two, the sodium salt slag is an alkaline slag obtained by filtering the filtrate of an alkaline desulfurization system, or is a sodium salt such as flake caustic soda, soda ash, or sodium sulfate, so as to reduce the viscosity of the upper floating slag, promote the separation of metal precipitation, and save the slag discharging time; the furnace temperature for reduction smelting is controlled at 1000°C to reduce the dust rate and the bismuth content in the dust.

[0025] The process for treating high-lead bismuth oxide slag in the oxygen-enriched side-blown furnace as described above: in the step three, in the copper removal by liquation process, the bismuth-lead alloy produced by reduction smelting is added to a copper removal by liquation pot, heated to 500-550 degrees, and the high-melting-point non-meltable substance is fished out, then cooled to 350 degrees, stirred, and the hull is added to adsorb and precipitate copper ash, so that the copper content is less than 1%, which is convenient for entering the vacuum furnace; wherein, the impurities such as antimony, arsenic, and tellurium form compounds together with copper to precipitate copper floating slag and copper-removed bismuth-lead alloy.

[0026] The process for treating high-lead-bismuth oxide slag in an oxygen-enriched side-blown furnace as described above: In step four, the low-silver crude bismuth and high-silver lead-bismuth residues obtained by two-stage vacuum distillation in a vacuum furnace, wherein the low-silver crude bismuth contains more than 90% bismuth and less than 40g / t of silver, simplifies the crude bismuth refining and deep processing process.

[0027] The process for treating high-lead-bismuth oxide slag in an oxygen-enriched side-blown furnace as described above: In step two, the ratio of lead-bismuth oxide slag to reducing coal is 100:2 to 6, so as to achieve complete reduction of bismuth and partial reduction of lead with a controlled reducing agent, thereby achieving preliminary separation of lead and bismuth; creating conditions for producing crude bismuth with a purity of over 90% without the use of chlorination for lead removal.

[0028] The lead-bismuth oxide slag is fed evenly for 2.2 hours per furnace, then reduced by interruption for 0.5 hours, and discharged for 10 minutes as one cycle. The reduction by interruption for no less than 0.5 hours is to achieve full reduction of bismuth.

[0029] The process for treating high-lead-bismuth oxide slag in an oxygen-enriched side-blown furnace as described above: In step four, during the first stage of the two-stage vacuum distillation in the vacuum furnace, the ratio of volatiles to residues is controlled to be 4-5:1; during the second stage of distillation, the ratio of volatiles to residues is controlled to be 2.5-1.5:1.

[0030] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention is a novel method for treating high-lead bismuth oxide slag in an oxygen-enriched side-blown furnace. The combustion and stirring of natural gas in the side-blown furnace, along with oxygen enrichment, accelerates heat transfer and chemical reaction rates. This saves 70% of the reaction time and approximately 60% of the processing costs. The reaction process has the function of preliminary separation of lead and bismuth. After separating gold and silver in a vacuum furnace, it can produce crude bismuth products with a bismuth content >90%, a bismuth + lead content >99%, and a silver content <40g / t. This significantly reduces the workload of subsequent refining processes for removing lead, arsenic, antimony, tellurium, and silver. It also significantly improves the efficiency and saves energy in the converter reduction smelting process for treating bismuth-lead oxide slag. Attached Figure Description

[0031] Figure 1 A flowchart of the process for treating high-lead-bismuth oxide slag in an oxygen-enriched side-blown furnace. Detailed Implementation

[0032] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0033] Implementation Case 1

[0034] Step 1. 189 tons of bismuth-lead oxide slag are uniformly fed into an oxygen-enriched side-blown furnace at a rate of 3.5 tons per hour. The auxiliary materials include 0.21 tons of reducing coal and 0.35 tons of sodium salt slag. Feeding is stopped after 8 tons of bismuth-lead slag have been added. The temperature is controlled at 1000-1100℃ for 0.5 hours of reduction, followed by 10 minutes of slag discharge. Each cycle takes approximately 3 hours, with a total duration of 92 hours. The furnace consumes 17189 m³ of natural gas, 17718 m³ of oxygen, 41126 kWh of electricity, and 13870 kg of reducing coal.

[0035] Step 2. Add bismuth and lead to the copper removal pot, heat to 500-550℃, remove the infusible solid, cool to about 350℃, stir and add rice husks, and stop stirring to remove copper slag after the scum becomes dry.

[0036] Step 3. After removing copper, bismuth and lead are distilled twice in a vacuum furnace. The volatiles from the first distillation are then distilled a second time. The product from the second distillation is crude bismuth containing an average of 90.57% bismuth, an average of 31 g / t of silver, and a bismuth plus lead content greater than 99%.

[0037] The following is a comparison of the unit consumption of lead-bismuth slag in oxygen-enriched side-blown furnace reduction smelting and lead-bismuth slag in converter reduction smelting:

[0038]

[0039]

[0040] The comparison shows that the side-blown furnace reduction smelting does not require auxiliary materials such as soda ash and fluorite balls, significantly reducing the consumption of natural gas, oxygen, and electricity. The unit cost decreased by 56.28% year-on-year. At the same time, the throughput of a converter of the same volume is 0.75 t / h, while that of an oxygen-enriched side-blown furnace is 2.05 t / h, which can save 69.51% of the processing time.

[0041] Implementation Case 2

[0042] Step 1. 222.49 tons of bismuth-lead oxide slag are uniformly fed into an oxygen-enriched side-blown furnace at a rate of 3.5 tons per hour. Auxiliary materials include 0.14 tons of reducing coal and 0.35 tons of sodium salt slag. Feeding is stopped after 8 tons of slag have been added. The temperature is controlled at 1000-1100℃ for 0.5 hours of reduction, followed by 10 minutes of slag discharge. Each cycle takes approximately 3 hours, with a total duration of 88 hours. Consumption includes 21,933 m³ of natural gas, 22,850 m³ of oxygen, 53,856 kWh of electricity, and 12,820 tons of reducing coal.

[0043] Step 2. Add bismuth and lead to the copper removal pot, heat to 500-550℃, remove the infusible solid, cool to about 350℃, stir and add rice husks, and stop stirring to remove copper slag after the scum becomes dry.

[0044] Step 3. After removing copper, bismuth and lead are distilled twice in a vacuum furnace. The volatiles from the first distillation are then distilled a second time. The product from the second distillation is crude bismuth with an average bismuth content of 91.88%, an average silver content of 28 g / t, and a bismuth plus lead content greater than 99%.

[0045] The following is a comparison of the unit consumption of lead-bismuth slag in oxygen-enriched side-blown furnace reduction smelting and lead-bismuth slag in converter reduction smelting:

[0046]

[0047]

[0048] The comparison shows that the side-blown furnace reduction smelting does not require auxiliary materials such as soda ash and fluorite balls, significantly reducing the consumption of natural gas, oxygen, and electricity. The unit cost decreased by 64.62% year-on-year. At the same time, the throughput of the same volume converter is 0.75 t / h, while that of the oxygen-enriched side-blown furnace is 2.52 t / h, saving 70.23% of the time.

[0049] Summary of Examples

[0050] Combining the above implementation cases one and two, and referring to... Figure 1 In summary, the embodiments of the present invention can be described as a process for treating high-lead-bismuth oxide slag in an oxygen-enriched side-blown furnace, specifically including the following steps:

[0051] Step 1, pyrometallurgical silver separation: High-silver precious lead is separated into lead-bismuth oxide slag with high silver content through pyrometallurgical silver separation. The lead content in the high-silver-content lead-bismuth oxide slag is <35%, and the lead-bismuth mass ratio is in the range of 0-0.8. After crushing the high-silver-content lead-bismuth oxide slag, it is uniformly conveyed to the feeding port of the oxygen-enriched side-blown furnace through a metering belt and fed into the oxygen-enriched side-blown furnace for reduction smelting.

[0052] The composition of the high-silver-content lead-bismuth oxide slag produced is as follows:

[0053]

[0054] Step two, reduction smelting, involves adding a reducing agent during the smelting process to perform limited reduction of the molten compound, partially separating lead and producing flue dust, low-bismuth high-lead reducing slag, and bismuth-lead alloy. The flue dust and low-bismuth high-lead reducing slag are returned to the lead system to recover lead and antimony. The reducing agent is reducing coal, and the ratio of lead-bismuth oxide slag to reducing coal is 100:2-6. This controlled reducing agent achieves complete reduction of bismuth and partial reduction of lead, achieving preliminary separation of lead and bismuth, and creating conditions for producing crude bismuth with over 90% purity without the use of chlorination for lead removal.

[0055] The composition of the reduced bismuth-lead alloy is as follows:

[0056]

[0057] The lead-bismuth oxide slag is fed evenly for 2.2 hours per furnace, then the furnace is shut down for 0.5 hours for reduction, and the slag is discharged for 10 minutes as one cycle. The furnace is shut down for no less than 0.5 hours for reduction to achieve full reduction of bismuth.

[0058] The reducing coal used in the limited reduction reaction during the smelting process is fueled by natural gas supplemented with 90% to 96% pure oxygen. The gas flow is forced through a high-pressure burner to stir the molten material in the furnace, thereby enhancing the reaction process and reaction rate. The added reducing coal is anthracite granules (carbon content greater than 80%), and its addition ratio is 2% to 6% of the dry weight of bismuth slag. This process is used to carry out limited reduction of lead bismuth oxide with high silver content, so as to initially separate lead and reduce the lead content of high silver bismuth lead alloy.

[0059] Sodium salt slag is added during the smelting process to lower the slag melting point, improve its fluidity, and promote metal precipitation and slag separation. The sodium salt slag is transported together with the reducing coal and the crushed silver-containing high-lead-bismuth oxide slag via a metering belt. The sodium salt slag is an alkaline slag obtained by filtering the filtrate from the alkaline desulfurization system, or sodium salts such as caustic soda, soda ash, and sodium sulfate to reduce the viscosity of the upper slag, promote metal sedimentation and separation, and save slag discharge time. During the reduction smelting process, no other auxiliary materials are needed except for the addition of reducing agents and alkaline slag. The furnace temperature is controlled at 1000℃ to reduce the dust rate and bismuth content in the dust.

[0060] Step 3: Copper Removal by Melting and Refining. The bismuth-lead alloy produced by reduction smelting is transferred to a copper removal pot to separate copper. During the copper removal process, the bismuth-lead alloy produced by reduction smelting is added to the copper removal pot, heated to 500-550 degrees Celsius, and high-melting-point infusible materials are removed. Then, the temperature is lowered to 350 degrees Celsius, and rice husks are added to adsorb and precipitate copper ash, making the copper content less than 1%, which is convenient for vacuum furnace loading. Among them, impurities such as antimony, arsenic, and tellurium form compounds with copper and precipitate together, producing copper dross and copper-removed bismuth-lead alloy.

[0061] The composition of the lead-bismuth alloy after copper removal is as follows:

[0062]

[0063] Step four: Bismuth-silver separation. After removing copper, the low-copper bismuth-lead alloy is vacuum distilled in a two-stage vacuum furnace to obtain low-silver crude bismuth and high-silver lead-bismuth residue, thus achieving efficient separation of bismuth and silver. During the first stage of the two-stage vacuum distillation, the ratio of volatiles to residues is controlled at 4-5:1, and during the second stage, the ratio is controlled at 2.5-1.5:1. The crude bismuth alloy is used for direct sale or refined using traditional chlorination processes. The low-silver crude bismuth and high-silver lead-bismuth residues obtained from the two-stage vacuum distillation have a bismuth content of over 90% and a silver content of less than 40 g / t, simplifying the crude bismuth refining and deep processing process.

[0064] The compositions of the low-silver crude bismuth and high-silver lead-bismuth residues obtained by two-stage vacuum distillation in a vacuum furnace are as follows:

[0065]

[0066] Step 5: Refining to produce silver. The high-silver lead-bismuth residue is returned to the silver separation furnace for oxidation refining to separate lead and bismuth, producing crude silver.

[0067] The above embodiments are exemplary and not restrictive. Therefore, any technical solutions that can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention are included within the scope of the present invention.

Claims

1. A process for treating high-lead-bismuth oxide slag in an oxygen-enriched side-blown furnace, characterized in that, Includes the following steps: Step 1, pyrometallurgical silver separation: high silver precious lead is separated into lead-bismuth oxide slag with high silver content through pyrometallurgical silver separation. The high silver content lead-bismuth oxide slag is crushed and then uniformly fed into the oxygen-enriched side-blown furnace through a metering belt for reduction smelting. Step 2, reduction smelting: During the smelting process, a reducing agent is added to perform limited reduction on the molten compound, partially separating lead and producing flue dust, low-bismuth high-lead reducing slag, and bismuth-lead alloy; wherein, the flue dust and low-bismuth high-lead reducing slag are returned to the lead system to recover lead and antimony, and the reducing agent is reducing coal; Sodium salt slag is also added during the smelting process to lower the slag melting point, improve its fluidity, and promote the precipitation and separation of metal from slag; the sodium salt slag is transported together with reducing coal and crushed silver-containing high-lead-bismuth oxide slag via a metering belt. Step 3: Copper removal by melting and precipitation. The bismuth-lead alloy produced by reduction smelting is transferred to a copper removal pot to separate copper. Step four: Bismuth-silver separation. After removing copper, the low-copper bismuth-lead alloy is vacuum distilled in a two-stage vacuum furnace to obtain low-silver crude bismuth and high-silver lead-bismuth residue, thus completing the efficient separation of bismuth and silver. The crude bismuth alloy is used for direct sale or refined by chlorination using traditional processes. Step 5: Refining to produce silver. The high-silver lead-bismuth residue is returned to the silver separation furnace for oxidation refining to separate lead and bismuth, producing crude silver.

2. The process for treating high-lead-bismuth oxide slag in an oxygen-enriched side-blown furnace according to claim 1, characterized in that, In step one, the lead-bismuth oxide slag with high silver content produced has a lead content of <35% and a lead-to-bismuth mass ratio in the range of 0-0.

8.

3. The process for treating high-lead-bismuth oxide slag in an oxygen-enriched side-blown furnace according to claim 1, characterized in that, In step two, the reducing coal used in the limited reduction reaction during the smelting process is fueled by natural gas supplemented with 90% to 96% pure oxygen, and the molten material in the furnace is forcibly stirred by the airflow injected through a high-pressure burner to enhance the reaction process and reaction rate. The added reducing coal is anthracite granules, and its addition ratio is 2% to 6% of the dry weight of bismuth slag. It performs limited reduction on lead bismuth oxide with high silver content to initially separate lead and reduce the lead content of high silver bismuth lead alloy.

4. The process for treating high-lead-bismuth oxide slag in an oxygen-enriched side-blown furnace according to claim 3, characterized in that, The anthracite particles used as a reducing agent have a carbon content greater than 80%.

5. The process for treating high-lead-bismuth oxide slag in an oxygen-enriched side-blown furnace according to claim 3, characterized in that, In step two, the sodium salt slag is the alkaline slag obtained by filtering the filtrate of the alkaline desulfurization system, or sodium salts such as caustic soda, soda ash, and sodium sulfate, in order to reduce the viscosity of the upper slag, promote metal sedimentation and separation, and save slag discharge time; the furnace temperature of the reduction smelting is controlled at 1000℃ to reduce the dust rate and the bismuth content of the dust.

6. The process for treating high-lead-bismuth oxide slag in an oxygen-enriched side-blown furnace according to claim 1, characterized in that, In step three, the copper removal process involves adding the bismuth-lead alloy produced by reduction smelting into a copper removal pot, heating it to 500-550 degrees Celsius, removing high-melting-point infusible materials, and then cooling it to 350 degrees Celsius while stirring and adding rice husks to adsorb and precipitate copper ash, so that the copper content is less than 1%, making it easier to feed into the vacuum furnace. Among these processes, impurities such as antimony, arsenic, and tellurium form compounds with copper and precipitate together, producing copper slag and copper-removed bismuth-lead alloy.

7. The process for treating high-lead-bismuth oxide slag in an oxygen-enriched side-blown furnace according to claim 1, characterized in that, In step four, the low-silver crude bismuth and high-silver lead-bismuth residues obtained by two-stage vacuum distillation in a vacuum furnace have a bismuth content of more than 90% and a silver content of less than 40g / t, which simplifies the crude bismuth refining and deep processing process.

8. The process for treating high-lead-bismuth oxide slag in an oxygen-enriched side-blown furnace according to claim 5, characterized in that, In step two, the ratio of lead-bismuth oxide slag to reducing coal is 100:2-6, so as to achieve complete reduction of bismuth and partial reduction of lead with a controlled reducing agent, thus achieving the initial separation of lead and bismuth; creating conditions for producing crude bismuth with a purity of over 90% without the use of chlorination for lead removal. The lead-bismuth oxide slag is fed evenly for 2.2 hours per furnace, followed by 0.5 hours of interrupted reduction and 10 minutes of slag discharge as one cycle. The interrupted reduction lasts for more than 0.5 hours to achieve full reduction of bismuth.

9. The process for treating high-lead-bismuth oxide slag in an oxygen-enriched side-blown furnace according to claim 7, characterized in that, In step four, during the first stage of the two-stage vacuum distillation process in the vacuum furnace, the ratio of volatiles to residues is controlled to be 4-5:1, and during the second stage of distillation, the ratio of volatiles to residues is controlled to be 2.5-1.5:1.

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