CN106498186B - A kind of method that bismuth sulfide material reduction sulphur fixing roast directly produces bismuth metal - Google Patents

Abstract

The invention discloses a method for directly producing metal bismuth by reducing and roasting bismuth sulfide materials for sulfur fixation. In the present invention, the bismuth sulfide material is scientifically reduced, sulfur-fixed and roasted to produce metal bismuth in one step; then the metal bismuth is obtained through simple and easy segregation and separation; and then the ferrous sulfide is melted and separated to complete bismuth from bismuth sulfide to metal bismuth and iron oxide. Sulfur fixation, valuable metal enrichment and other processes. The method of the invention can continuously process the bismuth sulfide concentrate on a large scale, and separate metal bismuth and ferrous sulfide. The direct recovery rate of metal bismuth is as high as 98.66%, and the separation rate of ferrous sulfide can reach more than 95%. The method of the invention has the advantages of simple operation, The characteristics of clean and comprehensive utilization can realize efficient utilization of iron resources in cinder and recovery of valuable metals, and it is easy to carry out industrial production.

Description

A method for direct production of metal bismuth by reducing sulfur-fixing roasting of bismuth sulfide materials

technical field

The invention relates to the technical field of metallurgy of non-ferrous metals, and more specifically relates to a method for extracting bismuth metal by reducing sulfur-fixing roasting of bismuth sulfide materials.

Background technique

Bismuth is a small metal but widely used in industrial fields such as biopharmaceuticals, coatings, electronics and glass. China has a lot of bismuth resources, among which Shizhuyuan in Hunan is the world's bismuth capital, but because the production scale is much smaller than that of lead, zinc and copper, its smelting and extraction methods are also more backward than those of bulk metals, and the main process is still reverberatory furnace precipitation For smelting, the main problem is the generation of low-concentration SO ₂ flue gas, and the consumption of iron powder and alkali is large.

In order to change this situation, since the 1960s, people have been carrying out new technology and basic theoretical research on clean bismuth smelting. The main processes include two routes: fire method and wet method. Among them, the fire method mainly includes reduction smelting, precipitation smelting, The lead-bismuth mixed smelting equipment is mainly completed in the reverberatory furnace. In recent years, the side blowing intensified smelting technology has been developed. However, the common problems of pyrotechnics are high smelting temperature, large consumption of iron powder and alkali, and easy generation of low-concentration sulfur dioxide flue gas.

The wet process includes ferric chloride leaching, chlorine gas leaching, alkaline leaching, chlorination hydrolysis, pulp electrolysis and pressure leaching. The advantage of the alkaline wet process is that the leaching rate is high, but there are disadvantages such as low current efficiency, high power consumption, high alkali consumption, etc., and the production cost and operating cost are high. The "new chlorination-hydrolysis method" recovers sulfur in the form of sulfur slag, eliminating the hazards of "sulfur smoke" in the fire method. The metal recovery rate is high and the comprehensive utilization is good, but there are problems such as large wastewater discharge and chlorine gas hazards. Slurry electrolysis shortens the process, but the current efficiency is low and the product quality is not high. Pressure leaching is rarely used due to problems such as equipment control and cost.

Patent CN103397182A discloses a method for efficiently recovering bismuth from monomeric bismuth ore. Bismuth metal is recovered by cyclone electrowinning after leaching bismuth ore with hydrochloric acid. Although the extraction of bismuth can be completed from low-concentration bismuth leachate, the leaching process Reagent consumption is large, and purification residue is difficult to open. Patent CN104726723A discloses a production process of bismuth smelting metallurgical charge. Its principle is based on mixed smelting and reduction smelting, which can process bismuth sulfide and bismuth oxide concentrate. The main problems are low bismuth output rate, difficult control conditions, and charge preparation. complex.

In addition, the main raw material for acid production in my country's sulfuric acid industry is pyrite. After the roasting is completed, a large amount of pyrite slag is produced. Its main component is iron oxide, and it also contains a large amount of valuable metals such as Ag and Au. Therefore, in the process of producing bismuth metal, how to reduce the generation of low _- concentration SO2 flue gas, reduce the consumption of iron powder and alkali consumption, and realize the clean and efficient utilization of iron resources in the slag while recovering valuable metals has always been an important issue. technical problems in the field.

Contents of the invention

The technical problem to be solved by the present invention is aimed at the existing problems in the current bismuth smelting process that a large amount of low _- concentration SO2 flue gas pollutes the environment, energy consumption is high, reagent consumption is large, and iron resources in the cinder cannot be simultaneously utilized and valuable metals can be recovered. The invention provides a method for directly producing metallic bismuth by reducing and roasting bismuth sulfide materials for sulfur fixation.

The purpose of the present invention is achieved through the following technical solutions:

Provided is a method for directly producing metal bismuth by reducing sulfur-fixing roasting of bismuth sulfide materials, comprising the following steps:

S1. Uniformly mix the bismuth sulfide material, sulfur-fixing agent, and reducing agent, and perform reduction-sulfur-fixing roasting under the condition of ≤800°C, and produce a sulfur-fixing roasted product mixed with metal bismuth and solid slag in one step;

S2. Add a salting-out agent to the sulfur-fixed roasted product obtained in step S1, and raise the temperature to 800-1000° C., so that the sulfur-fixed roasted product undergoes a melting and separation effect, and metal bismuth is separated from the molten slag;

S3. Add reducing agent and flux to the molten slag obtained in step S2, heat up to 1100-1200° C., slagging reaction, melting and separation, and obtain pyrite and waste slag after cooling;

Wherein, the salting-out agent described in step S2 is chloride.

The invention scientifically designs the production steps, the first step is sulfur-fixing roasting, the sulfur-fixing roasting step adds a sulfur-fixing agent and a reducing agent, does not add other additives, and directly produces a roasted product mixed with metal bismuth and solid slag at a lower roasting temperature ; The second step is to carry out melting and separation treatment by adding a reasonable salting-out agent to separate metal bismuth; reasonably adding a salting-out agent to make the metal bismuth particles produced by reduction roasting salt-out grow up, and melt and gather and solidify Slag separation. In the third step, by adding reducing agent and flux, melt separation treatment is carried out to separate ferrous sulfide. The separation rate is as high as 95%. Bismuth sulfide materials can be processed continuously on a large scale, and metal bismuth and ferrous sulfide can be separated, and the production process has the advantages of The characteristics of cleanness, low energy consumption and comprehensive utilization make it easy to carry out industrial production.

Preferably, the reduction and sulfur fixation calcination temperature in step S1 is 400-800° C., and the calcination time is 0.5-5 hours. Under the optimal temperature conditions, it is more favorable for the heterogeneous reaction of bismuth sulfide, iron oxide and carbonaceous reducing agent to reduce and fix sulfur, and the products are mainly metal bismuth, ferrous sulfide, unreacted gangue components and flue gas.

Further preferably, the reduction sulfur fixation calcination temperature is 500-800°C. It is further preferred that the roasting time for reducing sulfur fixation is 0.5-3 hours.

Preferably, the sulfur-fixing agent is pyrite slag or iron oxide concentrate.

Preferably, the added amount of the sulfur fixing agent is 100% to 150% of the theoretical amount of sulfur fixing, that is, 100 to 150% of the calculated amount of sulfur fixing according to formula (1) to formula (4), and the theoretical amount of sulfur fixing is calculated as Calculation of ferrous stoichiometric coefficients.

Further preferably, the amount of iron oxide added is 100-120% of the theoretical amount required for sulfur fixation, that is, 100-120% of the amount calculated for sulfur fixation according to formula (1) to formula (4). Containing Fe≥70%, Au≥30g/t, Ag≥80g/t, mainly produced in the sulfuric acid industry, in the process of reduction sulfur fixation roasting, reasonable iron is used for sulfur fixation, precious metals are enriched in coarse bismuth, Then through segregation and separation, metal bismuth and iron sulfide concentrates are obtained. Ferrous sulfide concentrate can be sold to steel mills, foundries, shipyards, etc., resulting in good economic benefits.

Preferably, the reducing agent in step S1 or step S3 is coal powder, pulverized coal or coke powder.

Further preferably, the amount of the reducing agent in step S1 is 3% to 20% of the mass of the bismuth sulfide material, and the amount of the reducing agent in step S3 is preferably 1% to 5% of the mass of the bismuth sulfide material. More preferably, the step The dosage of S1 reducing agent is 5-15% of the mass of bismuth sulfide concentrate.

Preferably, in step S2, the temperature is raised to 800-1000° C. and then kept for 0.5-3 hours.

Preferably, the chloride is sodium chloride, potassium chloride or calcium chloride.

Preferably, the salting-out agent is added in an amount of 1% to 5% of the mass of the bismuth sulfide material.

Preferably, the flux is iron oxide and/or calcium fluoride; preferably, the solvent is added in an amount of 1% to 10% of the mass of the molten slag.

Preferably, in step S3, the temperature is raised to 1100-1200°C and then kept for 0.5-3 hours.

The metal bismuth and ferrous sulfide roasted products obtained in the technical solution of the present invention are extracted by smelting metal bismuth, and the salting-out slag is melted to analyze the ferrous sulfide, the operation and control are simple, and the melting and separation tailings are unreacted gangue components, with stable properties And non-toxic, can be discarded directly.

At the reaction temperature set in the present invention, especially when the temperature is in the range of 400°C to 800°C, Bi ₂ S ₃ in the raw material and Fe ₂ O ₃ (Fe ₃ O ₄ ) in the auxiliary material and carbonaceous reducing agent mainly produce The following reduction roasting reaction:

Fe ₂ O ₃ (s)+C=2FeO(s)+CO(g) (1)

Fe ₃ O ₄ (s)+C=3FeO(s)+CO(g) (2)

Bi ₂ S ₃ (l)+3FeO(s)+3C(s)=2Bi(l)+3FeS(s)+3CO(g) (3)

Bi ₂ S ₃ (l) +3FeO(s)+3/2C(s)=2Bi(l)+3FeS(s)+3/2CO ₂ (g) (4)

During the above reaction process, the bismuth sulfide phase is converted into liquid metal bismuth and solid sulfide by solid oxide and carbon, and carbon oxide gas is released at the same time.

In step S2, in the temperature range of 800-1000° C., the segregation reaction of metal bismuth mainly occurs, and the metal bismuth is gathered together to be well separated from the solid slag.

When the temperature rises to 1100-1200°C in step S3, the gangue components in the slag undergo the reactions described in formula (5) to formula (7), and ferrous sulfide exists stably in the reducing atmosphere, and eventually becomes Separated from the slag, the following reactions mainly occur:

xFeO+ySiO ₂ +zCaO=xFeO·ySiO ₂ •zCaO (5)

xCaO+SiO ₂ =xCaO·SiO ₂ (6)

2FeO+SiO ₂ =2FeO·SiO ₂ (7)

The technical solution of the invention is especially suitable for bismuth sulfide concentrate.

Compared with the prior art, the beneficial effects of the present invention are:

In the present invention, the bismuth sulfide material is scientifically reduced, sulfur-fixed and roasted to produce metal bismuth in one step; then the metal bismuth is obtained through simple and easy segregation and separation; and then the ferrous sulfide is melted and separated to complete bismuth from bismuth sulfide to metal bismuth and iron oxide. In the process of sulfur fixation and valuable metal enrichment, the direct recovery rate of bismuth metal is 95% to 98.66%, and the separation rate of ferrous sulfide is as high as 95%. It can continuously process bismuth sulfide materials on a large scale, and separate bismuth metal and sulfide Ferrous, and the process has the characteristics of cleanness, low energy consumption, and comprehensive utilization. The process of the present invention belongs to a clean, environmentally friendly, low-carbon, and short-flow bismuth smelting process. It is characterized by low sulfur-fixing roasting temperature, high bismuth conversion rate, and process operation It is simple, consumes less reagents, does not produce a large amount of low-concentration SO ₂ flue gas, and reduces pollution. The roasting equipment can adopt the large-scale equipment commonly used in the existing smelting process that can be continuously operated, and it is easy to carry out large-scale industrial production.

Further, on the basis of the basic design idea of the present invention, the sulfur-fixing agent preferably adopts pyrite slag, which is a by-product of the sulfuric acid industry, which is refractory to treatment and utilization, and performs reduction and sulfur-fixing roasting of bismuth sulfide concentrate to realize high-efficiency utilization of slag. iron resources and recover valuable metals.

Description of drawings

Accompanying drawing 1 bit process flow chart of the present invention.

Detailed ways

The present invention will be further described below in conjunction with specific examples. The following examples are for illustrative purposes only, and should not be construed as limiting the present invention. Unless otherwise specified, the raw materials and equipment used in the following examples are those conventionally used in the art.

Example 1

Process flow chart of the present invention is as shown in accompanying drawing 1.

The main chemical components (wt.%) of the bismuth sulfide material used as the test raw material in this example are: Bi 25.18, Fe19.33, S 21.25, Al 1.46, Ca 3.30, Cu 1.99, Mo 2.23, Pb 2.78, SiO ₂ 12.67 The chemical composition of pyrite slag is (wt.%): Fe 71.30, S 1.72, Zn 1.28, SiO ₂ 10.57, CaO 2.14, Ag 850g/t; the chemical composition of iron oxide concentrate (wt.%) is : Fe ₂ O ₃ 89.30, SiO ₂ 4.42, CaO 1.14, Al ₂ O ₃ 1.81, MgO 0.29; the chemical composition (wt. %) of reduced coal powder is: C 82.33, S 2.01, SiO ₂ 6.66, CaO 0.83, Al ₂ O ₃ 4.81, MgO 0.23; chemical composition (wt. %) of reduced coke powder is C 85.73, S 2.23, ash 11.03.

S1. Weigh 100g of bismuth sulfide material, 32g of pyrite slag, and 10g of coal powder with the above ingredients, mix them evenly, put them into a graphite crucible, put them into an electric furnace and roast at 700°C for 2.0h. After cooling, 129.13g of roasted product was obtained, the main components were Bi18.75%, Fe 30.27%, S 14.92%. XRD and phase analysis showed that the bismuth phase was mainly metal bismuth, accounting for 95.35% of the total bismuth, and the iron phase was mainly It is FeS, and the calculated sulfur fixation rate is 90.34%.

S2. Add 2gNaCl to the roasted product, then rapidly raise the temperature to 950°C and keep it warm for 0.5h, separate the metal and slag after cooling, and obtain 24.70g of crude metal bismuth, which contains 96.04% of bismuth after analysis, and the direct yield of bismuth is calculated 94.20%.

S3. Add 3g of coal powder and 6.5g of iron oxide slag to the molten slag, raise the temperature to 1200°C and hold it for 1.0h, then cool the sample, separate the lower layer of sulfide and upper layer of slag, the masses are 56.54g and 52.17g respectively. The sulfur and iron contents were analyzed separately, and the total sulfur fixation rate of ferrous sulfide and slag was calculated to be 97.31%, and the separation rate of ferrous sulfide was 96.33%.

During the test, no pungent gas (SO ₂ ) was produced. During the roasting process of step S1, a small amount of flue gas is produced. The present invention adopts the method of bag dust collection to collect the flue dust and a very small amount of waste gas. The waste gas can be directly emptied without generating pungent gas. The soot can be returned to step S1 for reduction, sulfur fixation and roasting for reuse.

Example 2

Test raw materials, reagents and steps are the same as in Example 1.

Weigh 100g of bismuth sulfide material (concentrate), 32g of pyrite slag, and 10g of coal powder with the above ingredients, mix them uniformly, put them into a graphite crucible, put them into an electric furnace and roast at 750°C for 2.0h. After cooling, 127.42 g of roasted products were obtained, the main components being Bi 18.29%, Fe 31.02%, and S 13.97%. XRD and phase analysis show that metal bismuth accounts for 93.11% of the total bismuth in the bismuth phase, the iron phase is mainly FeS, and the calculated sulfur fixation rate is 85.74%. After adding 3g of KCl to the roasted product, the temperature was raised rapidly to 1000°C and held for 0.5h. After cooling, the metal and solid slag were separated to obtain 25.26g of crude metal bismuth, which contained 96.22% of bismuth after analysis, and the direct yield of bismuth was calculated to be 96.51%.

After adding 3g of coal powder and 8.0g of iron oxide slag to the molten slag, the temperature was raised to 1150°C and kept for 1.0h, then the sample was cooled, and the lower layer of sulfide and upper layer of slag were separated, with masses of 49.17g and 52.33g, respectively. The sulfur and iron contents were analyzed separately, and the total sulfur fixation rate of ferrous sulfide and slag was calculated to be 92.76%, and the separation rate of ferrous sulfide was 95.02%.

During the test, no pungent gas (SO ₂ ) was produced. During the roasting process of step S1, a small amount of flue gas is produced. The present invention adopts the bag dust collection method to collect the flue dust and a very small amount of waste gas. The waste gas can be directly emptied without generating pungent gas. The soot can be returned to step S1 for reduction, sulfur fixation and roasting for reuse.

Example 3

Test raw materials, reagents and steps are the same as in Example 1.

Weigh 100g of bismuth sulfide material (concentrate), 32g of iron oxide concentrate, and 10g of coke powder with the above ingredients, mix them uniformly, put them into a graphite crucible, and put them into an electric furnace for 2.0 hours at 400°C. After cooling, 127.42 g of roasted products were obtained, the main components of which were Bi 18.75%, Fe 30.66%, and S 14.39%. The phase analysis shows that metal bismuth accounts for 55.82% of the total bismuth in the bismuth phase, and the sulfur phase is mainly FeS, and the calculated sulfur fixation rate is 82.43%. After adding 3g NaCl to the roasted product, the temperature was raised rapidly to 800°C and held for 2 hours. After cooling, the metal and solid slag were separated to obtain 22.35g of crude metal bismuth, which contained 93.37% of bismuth after analysis, and the direct yield of bismuth was calculated to be 82.86%.

After adding 3g of coal powder and 8.0g of iron oxide slag to the slag, the temperature was raised to 1100°C and kept for 1.0h, then the sample was cooled, and the lower layer of sulfide and upper layer of slag were separated, with masses of 35.72g and 62.45g, respectively. The sulfur and iron contents were analyzed separately, and the total sulfur fixation rate of ferrous sulfide and slag was calculated to be 97.66%, and the separation rate of ferrous sulfide was 95.34%.

During the test, no pungent gas (SO ₂ ) was produced. During the roasting process of step S1, a small amount of flue gas is produced. The present invention adopts the bag dust collection method to collect the flue dust and a very small amount of waste gas. The waste gas can be directly emptied without generating pungent gas. The soot can be returned to step S1 for reduction, sulfur fixation and roasting for reuse.

Example 4

Test raw materials, reagents and steps are the same as in Example 1.

Weigh 500g of bismuth sulfide material (concentrate), 190g of pyrite slag, and 60g of coke powder with the above ingredients, mix them evenly, put them into a graphite crucible, put them into an electric furnace and roast at 800°C for 0.5h. After cooling, 648.13g of roasted product was obtained, and the main components were Bi 19.07%, Fe 32.46%, and S 16.03%. The phase analysis shows that metal bismuth accounts for 98.78% of the total bismuth in the bismuth phase, the iron phase is mainly FeS, and the calculated sulfur fixation rate is 93.56%. After adding 5g of KCl to the roasted product, the temperature was raised rapidly to 1000°C and held for 0.5h. After cooling, the metal and solid slag were separated to obtain 130.53g of crude metal bismuth, which contained 91.27% of bismuth after analysis, and the direct yield of bismuth was calculated to be 95.30%. .

After adding 5g of coal powder, 5g of iron oxide slag and 10g of calcium fluoride to the slag, the temperature was raised to 1100°C and kept for 3.0h, then the sample was cooled, and the lower layer of sulfide and upper layer of slag were separated, with masses of 272.18g and 268.17g, respectively. The sulfur and iron contents were analyzed separately, and the total sulfur fixation rate of ferrous sulfide and slag was calculated to be 95.11%, and the separation rate of ferrous sulfide was 96.30%.

During the test, no pungent gas (SO ₂ ) was produced. During the roasting process of step S1, a small amount of flue gas is produced. The present invention adopts the method of bag dust collection to collect the flue dust and a very small amount of waste gas. The waste gas can be directly emptied without generating pungent gas. The soot can be returned to step S1 for reduction, sulfur fixation and roasting for reuse.

Example 5

Test raw materials, reagents and steps are the same as in Example 1.

Weigh 500g of bismuth sulfide concentrate, 160g of iron oxide concentrate, and 60g of coke powder with the above components, mix them uniformly, put them into a graphite crucible, put them into an electric furnace and roast at 600°C for 5.0h. After cooling, 591.27g of roasted product was obtained, the main components were Bi19.83%, Fe30.44%, S15.75%. The phase analysis shows that metal bismuth accounts for 97.33% of the total bismuth in the bismuth phase, and the iron phase is mainly FeS, and the calculated sulfur fixation rate is 89.72%. After adding 15g NaCl to the roasted product, the temperature was rapidly raised to 850°C and kept for 3.0 hours. After cooling, the metal and solid slag were separated to obtain 128.64g of crude metal bismuth, which contained 96.56% of bismuth after analysis, and the direct yield of bismuth was calculated to be 98.66% .

Add 15g of coal powder, 20g of iron oxide slag and 10g of calcium fluoride to the molten slag, raise the temperature to 1200°C and hold it for 0.5h, then cool the sample, separate the lower layer of sulfide and upper layer of slag, the masses are 241.74g and 266.22g, respectively. The sulfur and iron contents were analyzed respectively, and the total sulfur fixation rate of ferrous sulfide and slag was calculated to be 96.02%, and the separation rate of ferrous sulfide was 98.04%.

During the test, no pungent gas (SO ₂ ) was produced. During the roasting process of step S1, a small amount of flue gas is produced. The present invention adopts the bag dust collection method to collect the flue dust and a very small amount of waste gas. The waste gas can be directly emptied without generating pungent gas. The soot can be returned to step S1 for reduction, sulfur fixation and roasting for reuse.

Example 6

Test raw materials, reagents and steps are the same as in Example 1.

Weigh 500g of bismuth sulfide concentrate, 130g of iron oxide concentrate, and 40g of coke powder with the above components, mix them uniformly, put them into a graphite crucible, put them into an electric furnace and roast at 800°C for 2.0h. After cooling, 565.39 g of roasted products were obtained, the main components of which were Bi19.22%, Fe 29.71%, and S 15.23%. The phase analysis shows that metal bismuth accounts for 98.59% of the total bismuth in the bismuth phase, the iron phase is mainly FeS, and the calculated sulfur fixation rate is 94.34%. Add 25g NaCl to the roasted product, then rapidly raise the temperature to 800°C and keep it warm for 1.0h, separate the metal and solid slag after cooling, and obtain 128.64g of crude metal bismuth, which contains 95.27% of bismuth after analysis, and the direct yield of bismuth is calculated to be 97.54% .

Add 25g of coal powder, 45g of iron oxide slag and 5g of calcium fluoride to the molten slag, raise the temperature to 1150°C and hold it for 1.0h, then cool the sample, separate the lower layer of sulfide and upper layer of slag, the masses are 240.72g and 270.11g, respectively. The sulfur and iron contents were analyzed respectively, and the total sulfur fixation rate of ferrous sulfide and slag was calculated to be 97.73%, and the separation rate of ferrous sulfide was 98.25%.

During the test, no pungent gas (SO ₂ ) was produced. During the roasting process of step S1, a small amount of flue gas is produced. The present invention adopts the method of bag dust collection to collect the flue dust and a very small amount of waste gas. The waste gas can be directly emptied without generating pungent gas. The soot can be returned to step S1 for reduction, sulfur fixation and roasting for reuse.

Claims (8)

1. a kind of method that bismuth sulfide material reduction sulphur fixing roast directly produces bismuth metal, which is characterized in that include the following steps：

S1. bismuth sulfide material, sulphur-fixing agent, reducing agent are uniformly mixed, carries out reduction sulphur fixing roast, a step output bismuth metal and solid The sulphur fixing roast product of state slag mixing；

S2. salting-out agents are added into sulphur fixing roast product obtained by step S1, are warming up to 800~1000 DEG C, make sulphur fixing roast product Liquate centrifugation occurs, bismuth metal is detached with scoria；

S3. reducing agent and flux are added into scoria obtained by step S2, is warming up to 1100~1200 DEG C, slag making reaction melts Separation obtains troilite and waste after cooling；

Wherein, it is 400~800 DEG C that sulphur fixing roast temperature is restored described in step S1, and the time of roasting is 0.5~5h；Step S2 institutes The salting-out agents stated are chloride, and the chloride is sodium chloride, potassium chloride or calcium chloride；Flux described in step S3 is iron oxide And/or calcirm-fluoride.

2. the method that bismuth sulfide material reduction sulphur fixing roast according to claim 1 directly produces bismuth metal, feature exist In sulphur-fixing agent described in step S1 is pyrite cinder or iron oxide concentrate.

3. the method that bismuth sulfide material reduction sulphur fixing roast according to claim 2 directly produces bismuth metal, feature exist In, the addition of the sulphur-fixing agent is the 100%~150% of solid sulphur theoretical amount, Gu sulphur theoretical amount presses ferrous sulfide stoichiometry Coefficient calculates.

4. the method that bismuth sulfide material reduction sulphur fixing roast according to claim 1 directly produces bismuth metal, feature exist The reducing agent described in, step S1 or step S3 is coal dust, broken coal or coke powder；The dosage of reducing agent described in step S1 is bismuth sulfide object Expect the 3%~20% of quality, the dosage of reducing agent described in step S3 is the 1%~5% of bismuth sulfide quality of material.

5. the method that bismuth sulfide concentrate reduction sulphur fixing roast according to claim 1 directly produces bismuth metal, feature exist In 0.5~3h of heat preservation after being warming up to 800~1000 DEG C described in step S2.

6. the method that bismuth sulfide material reduction sulphur fixing roast according to claim 1 directly produces bismuth metal, feature exist In the addition of the salting-out agents is the 1%~5% of bismuth sulfide quality of material.

7. the method that bismuth sulfide material reduction sulphur fixing roast according to claim 1 directly produces bismuth metal, feature exist In the addition of flux described in step S3 is the 1%~10% of scoria quality.

8. the method that bismuth sulfide concentrate reduction sulphur fixing roast according to claim 1 directly produces bismuth metal, feature exist In 0.5~3h of heat preservation after being warming up to 1100~1200 DEG C described in step S3.