阅读说明：本技术 一种粗铋分步精炼的方法及其使用的连续式真空炉 (Method for refining crude bismuth step by step and continuous vacuum furnace used by same ) 是由 吴世军 黄志荣 于 2020-07-28 设计创作，主要内容包括：本发明涉及金属冶炼技术领域,且公开了一种粗铋分步精炼的方法,包括如下工艺步骤：熔化捞渣,将粗铋装入精铋锅,采用天然气加热,升温至600℃时首先捞去熔化渣；将温度降至500℃,捞去除铜渣；再将温度降至280～330℃,加入硫磺粉脱铜,硫磺粉用量约为0.2％,搅拌2～4小时左右即可第二次捞渣,上述渣统称除铜渣,返回鼓风炉配料。该粗铋分步精炼的方法及其使用的连续式真空炉,通过分步反应,使得粗铋的产出精度更高,且每个步骤产出的不同的废料后续也可以分别使用到不同的工厂进行加工节省能源消耗,同时也利于环境的保护,再有每个产出步骤的发生装置不一致,可以节约等待冷却的时间,缩短生产的时长,提高生产效率。(The invention relates to the technical field of metal smelting, and discloses a method for refining crude bismuth step by step, which comprises the following process steps: melting and fishing slag, putting the crude bismuth into a refined bismuth pot, heating by adopting natural gas, and fishing out the melting slag when the temperature is raised to 600 ℃; reducing the temperature to 500 ℃, and removing copper slag by fishing; and then cooling to 280-330 ℃, adding sulfur powder for decoppering, wherein the using amount of the sulfur powder is about 0.2%, stirring for about 2-4 hours, and then fishing out slag for the second time, wherein the slag is collectively called copper-removing slag, and returning to the blast furnace for batching. This method of crude bismuth step refining and continuous type vacuum furnace who uses thereof through the substep reaction for the output precision of crude bismuth is higher, and the follow-up waste material that also can use respectively of the difference of every step output different mills to process the energy saving consumption, also does benefit to the protection of environment simultaneously, and the generating device who has every output step is inconsistent again, can practice thrift the time of waiting for the cooling, shortens the length of production, improves production efficiency.)

1. The method for refining the crude bismuth step by step is characterized by comprising the following process steps of:

melting and fishing slag, putting the crude bismuth into a refined bismuth pot, heating by adopting natural gas, and fishing out the melting slag when the temperature is raised to 600 ℃; reducing the temperature to 500 ℃, and removing copper slag by fishing;

cooling to 280-330 ℃, adding sulfur powder for decoppering, wherein the amount of the sulfur powder is about 0.2%, stirring for about 2-4 hours to obtain slag for the second time, wherein the slag is totally called copper-removing slag, and returning to a blast furnace for batching;

and (3) oxidizing and refining, namely heating the bismuth liquid to 680-750 ℃ after copper removal, and blowing compressed air to perform oxidation and impurity removal.

2. The method for fractional refining of crude bismuth as claimed in claim 1, wherein: and lead-removing refining, namely controlling the temperature of the antimony-removed bismuth liquid to be 450-480 ℃, introducing chlorine gas into the bismuth liquid through a gas transmission pipeline, and reacting lead in the bismuth liquid with the chlorine to generate lead chloride.

3. The method for fractional refining of crude bismuth as claimed in claim 2, wherein: alkaline refining, heating the lead-removed bismuth solution to 500-520 ℃, adding sodium hydroxide, introducing compressed air into the bismuth solution to react tellurium with oxygen in the air to produce tellurium dioxide, and reacting tellurium which does not react with the compressed air with alkali to generate Na₂TeO₃Both of which are solid phases, separated from the bismuth solution.

4. The method for fractional refining of crude bismuth as claimed in claim 3, wherein: and finally, refining, namely controlling the temperature of the bismuth liquid for removing tellurium at 680-720 ℃, adding sodium hydroxide with the weight of 0.5-1% of the material weight, blowing compressed air into the bismuth liquid, stirring for 2 hours, then sampling and analyzing, obtaining refined bismuth when the lead content in the bismuth liquid is less than 0.001% and the silver content in the bismuth liquid is less than 0.003%, and cooling to 320-400 ℃ to cast a bismuth ingot by using a vertical die.

5. The method for fractional refining of crude bismuth as claimed in claim 1, wherein: in the oxidation refining process, when the amount of flue gas is reduced and a small amount of lead oxide appears on the surface of the bismuth liquid, the antimony removal end point is obtained, and the time is 4-10 hours.

6. The method for fractional refining of crude bismuth as claimed in claim 2, wherein: in the lead-removing refining process, the number of the gas transmission pipelines is six, and the depth of the gas transmission pipelines is 300-400 mm.

7. The method for fractional refining of crude bismuth as claimed in claim 3, wherein: in the alkaline refining process, the adding amount of sodium hydroxide is 1.5-2% of the weight of the material, the time is 6-10 hours, and the tellurium removal end point is obtained when the added solid alkali is not dried any more under the stirring of compressed air.

8. The continuous vacuum furnace for the fractional refining of crude bismuth according to claim 1, characterized in that the apparatus mainly comprises: the device comprises a smelting pot, a heating device, a temperature control device, a ventilation device, a stirring device, a slag dragging device and a feeding device, wherein the heating device is arranged below the smelting pot, the temperature control device and the stirring and feeding device are arranged beside the smelting pot, the temperature control device triggers the slag dragging device when the temperature in a refining container reaches 300-400 ℃ and 600-700 ℃, the ventilation device comprises an air blower and a bismuth liquid surface air guide pipe inserted into the smelting pot, the temperature control device triggers the feeding device to add alkali or wood dust when the temperature in the smelting pot reaches 450-550 ℃, and the smelting pot is a cast iron pot or a cast steel pot; the stirring device and the slag dragging device are the same device, and the heating device is an electric heating device, a fuel oil heating device or a coal heating device.

Technical Field

The invention relates to the technical field of metal smelting, in particular to a method for refining crude bismuth step by step and a continuous vacuum furnace used by the method.

Background

Bismuth can be made into low-melting-point alloy and used in an automatic closer or a type alloy; bismuth oxycarbonate and bismuth oxynitrate as medicaments; bismuth oxide is used in the glass and ceramic industries; bismuth compounds are added into cosmetics as bleaching agents and pearling agents, the content of bismuth in the earth crust is only about 10-6%, single primary natural bismuth ore is rarely seen, most bismuth ore coexists with metal minerals such as tungsten, molybdenum, lead, copper, iron and the like, so that bismuth is generally recovered from byproducts in the refining process of other main metals, the byproducts of bismuth in certain processes exist in the form of high-copper and high-silver bismuth alloys, and the conventional general crude bismuth refining method has strict requirements on impurity elements in crude bismuth, so that the crude bismuth refining device has higher requirements, and therefore, a crude bismuth step-by-step refining method and a continuous vacuum furnace used by the method are provided.

Disclosure of Invention

The invention provides a method for refining crude bismuth step by step and a continuous vacuum furnace used by the method, which have the advantage of removing impurities by multi-step operation and solve the problems of poor impurity removal effect and low purity of produced refined bismuth.

The invention provides the following technical scheme: a method for refining crude bismuth step by step comprises the following process steps:

melting and fishing slag, putting the crude bismuth into a refined bismuth pot, heating by adopting natural gas, and fishing out the melting slag when the temperature is raised to 600 ℃; reducing the temperature to 500 ℃, and removing copper slag by fishing;

cooling to 280-330 ℃, adding sulfur powder for decoppering, wherein the amount of the sulfur powder is about 0.2%, stirring for about 2-4 hours to obtain slag for the second time, wherein the slag is totally called copper-removing slag, and returning to a blast furnace for batching;

and (3) oxidizing and refining, namely heating the bismuth liquid to 680-750 ℃ after copper removal, and blowing compressed air to perform oxidation and impurity removal.

And lead-removing refining, namely controlling the temperature of the antimony-removed bismuth liquid to be 450-480 ℃, introducing chlorine gas into the bismuth liquid through a gas transmission pipeline, and reacting lead in the bismuth liquid with the chlorine to generate lead chloride.

Alkaline refining, heating the lead-removed bismuth solution to 500-520 ℃, adding sodium hydroxide, introducing compressed air into the bismuth solution to react tellurium with oxygen in the air to produce tellurium dioxide, and reacting tellurium which does not react with the compressed air with alkali to generate Na₂TeO₃Both of which are in solid phase, from bismuth solutionsIs separated out.

And finally, refining, namely controlling the temperature of the bismuth liquid for removing tellurium at 680-720 ℃, adding sodium hydroxide with the weight of 0.5-1% of the material weight, blowing compressed air into the bismuth liquid, stirring for 2 hours, then sampling and analyzing, obtaining refined bismuth when the lead content in the bismuth liquid is less than 0.001% and the silver content in the bismuth liquid is less than 0.003%, and cooling to 320-400 ℃ to cast a bismuth ingot by using a vertical die.

Preferably, in the oxidation refining process, when the smoke gas amount is reduced and a small amount of lead oxide appears on the surface of the bismuth liquid, the antimony removal end point is obtained, and the time is 4-10 hours.

Preferably, in the lead-removing refining process, the number of the gas transmission pipelines is six, and the depth is 300-400 mm.

Preferably, in the alkaline refining process, the adding amount of the sodium hydroxide is 1.5-2% of the weight of the material, the time is 6-10 hours, and the tellurium removal end point is obtained when the added solid alkali is not dried any more under the stirring of compressed air.

A continuous vacuum furnace for refining crude bismuth step by step mainly comprises: the device comprises a smelting pot, a heating device, a temperature control device, a ventilation device, a stirring device, a slag dragging device and a feeding device, wherein the heating device is arranged below the smelting pot, the temperature control device and the stirring and feeding device are arranged beside the smelting pot, the temperature control device triggers the slag dragging device when the temperature in a refining container reaches 300-400 ℃ and 600-700 ℃, the ventilation device comprises an air blower and a bismuth liquid surface air guide pipe inserted into the smelting pot, the temperature control device triggers the feeding device to add alkali or wood dust when the temperature in the smelting pot reaches 450-550 ℃, and the smelting pot is a cast iron pot or a cast steel pot; the stirring device and the slag dragging device are the same device, and the heating device is an electric heating device, a fuel oil heating device or a coal heating device.

The invention has the following beneficial effects:

this method of crude bismuth step refining and continuous type vacuum furnace who uses thereof through the substep reaction for the output precision of crude bismuth is higher, and the follow-up waste material that also can use respectively of the difference of every step output different mills to process the energy saving consumption, also does benefit to the protection of environment simultaneously, and the generating device who has every output step is inconsistent again, can practice thrift the time of waiting for the cooling, shortens the length of production, improves production efficiency.

Drawings

FIG. 1 is a schematic flow chart of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1, a method for refining crude bismuth step by step includes the following process steps:

step 1, melting and dragging slag and oxidizing refining

Putting the crude bismuth into a refined bismuth pot, heating by adopting natural gas, and fishing out molten slag when the temperature is 600 ℃;

reducing the temperature to 500 ℃, and removing copper slag by fishing;

and then cooling to 280-330 ℃, adding sulfur powder for decoppering, wherein the using amount of the sulfur powder is about 0.2%, stirring for about 2-4 hours, and then fishing out slag for the second time, wherein the slag is collectively called copper-removing slag, and returning to the blast furnace for batching.

Heating the bismuth liquid to 680-750 ℃ after decoppering, blowing compressed air for oxidation and impurity removal, wherein the difference between the free enthalpies of oxides of metal impurities such as antimony and bismuth oxides is large, so that the metal impurities such as antimony are preferentially oxidized and separated from bismuth in oxidation refining, most of antimony oxide volatilizes into gas, and if the blown compressed air is too large, more bismuth is oxidized, so that the reaction process must be strictly controlled, generally, when the smoke gas quantity is reduced and a small amount of lead oxide appears on the surface of the bismuth liquid, the antimony removal end point is regarded as the antimony removal end point, the time is 4-10 hours, and the main reaction formula of the oxidation refining is as follows:

4Bi+3O₂＝2Bi₂O₃

4Sb+3O₂＝2Sb₂O₃

Sb₂O₃+O₂＝Sb₂O₅

Bi₂O₃+2Sb＝Sb₂O₃+2Bi

step 2, lead removal refining

Controlling the temperature of the antimony-removed bismuth liquid at 450-480 ℃, introducing 6 glass tubes into each pot, wherein the depth of each pot is 300-400 mm, introducing chlorine into the bismuth liquid, reacting lead with the chlorine to generate lead chloride, and repeatedly performing lead removal operation, wherein the main reaction formula of lead removal refining is as follows:

Cl₂+Pb＝PbCl₂

2Bi+3Cl₂＝2BiCl₃

step 3, alkaline refining

The purpose of the alkaline refining is to remove tellurium. Heating the bismuth liquid to 500-520 ℃, adding sodium hydroxide, introducing compressed air into the bismuth liquid to react tellurium with oxygen in the air to produce tellurium dioxide, and reacting tellurium which does not react with the compressed air with alkali to generate Na2TeO3, wherein the tellurium dioxide and the tellurium are solid phases which are separated from the bismuth liquid, and the main reaction formula of alkaline refining is as follows:

Te+O₂＝TeO₂,

TeO₂+2NaOH＝Na₂TeO₃+H₂O

tellurium, which has not reacted with compressed air, reacts with alkali as follows:

3Te+6NaOH＝2Na₂Te+Na₂TeO₃+3H₂O

the adding amount of the sodium hydroxide is 1.5-2% of the weight of the material, the tellurium removal time is about 6-10 h, and the tellurium removal end point is obtained when the added solid alkali is not dried any more under the stirring of compressed air.

Step 4, final refining

In order to remove residual trace elements which are easier to oxidize than bismuth, such as chlorine, zinc, antimony, tellurium, iron, lead and the like, final refining is carried out, the temperature of bismuth liquid is controlled to be 680-720 ℃, sodium hydroxide with the weight of 0.5-1% of the material weight is added, compressed air is blown into the bismuth liquid to be stirred for 2 hours, then sampling analysis is carried out, when the lead content in the bismuth liquid is less than 0.001% and the silver content in the bismuth liquid is less than 0.003%, refined bismuth is obtained, and after the temperature is reduced to 320-400 ℃, bismuth ingots are cast by a vertical die.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.