CN212451580U - Slag dragging device for crude tin refining - Google Patents
Slag dragging device for crude tin refining Download PDFInfo
- Publication number
- CN212451580U CN212451580U CN202021182746.6U CN202021182746U CN212451580U CN 212451580 U CN212451580 U CN 212451580U CN 202021182746 U CN202021182746 U CN 202021182746U CN 212451580 U CN212451580 U CN 212451580U
- Authority
- CN
- China
- Prior art keywords
- slag
- tin
- refining pot
- tin refining
- slag conveyor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Manufacture And Refinement Of Metals (AREA)
Abstract
A slag dragging device for crude tin refining comprises a tin refining pot, a stirrer and a slag dragging machine; the tin refining pot is a steel crude tin refining pot; the stirrer is arranged on one side of the tin refining pot through a stirrer mounting foot stand and can rotate up and down around the stirrer rotating device to place or remove the stirring paddle into or out of a tin liquid layer in the tin refining pot; the slag conveyor is arranged at the other side of the tin refining pot through a slag conveyor mounting foot stool, and can rotate up and down around a slag conveyor rotating system to place or move a scum inlet of the slag conveyor out of a scum layer of the tin refining pot. The utility model discloses a replace the manual work to pull out the charcoal sediment of taking off arsenic and iron, the sulphur sediment of decoppering, the aluminium sediment of antimony of taking off by dragging for the sediment device, reduce the energy consumption, reduce personnel intensity of labour and occupational hazard, increased substantially work efficiency.
Description
Technical Field
The utility model belongs to the technical field of non ferrous metal metallurgy, concretely relates to slag dragging device of crude tin refining.
Background
The fire refining of crude tin generally needs to remove arsenic, iron, copper, antimony, lead, bismuth, gold, silver, indium and the like contained in the crude tin respectively according to different impurities contained in the crude tin, and the adopted method is to respectively remove different impurities in different devices by adopting a physical or chemical method and adding reagents, physical liquation, condensation and the like.
The arsenic and iron are removed in an oxidation pot by adding sawdust, stirring at a proper temperature, adsorbing arsenic and iron in the crude tin on the surface of the heated carbonized sawdust, floating the arsenic and iron on the liquid crude tin, and manually fishing out carbon slag containing arsenic and iron by using a strainer.
The copper removal is completed in a copper removal pot, generally, tin liquid after arsenic and iron removal is transferred to the copper removal pot, the temperature is raised to the temperature required by the copper removal, sulfur is added according to the copper-containing condition of the tin liquid, the copper in the crude tin and the sulfur react to generate large-particle cuprous sulfide, the cuprous sulfide floats out of the liquid crude tin, and the carbon slag containing the cuprous sulfide is manually fished out by using a strainer.
The crude tin without copper is treated by an electrothermal mechanical crystallizer to remove impurities such as lead, bismuth and the like, crystalline granular tin is fused in a tin combining pot, the temperature is raised to the temperature required by removing antimony, aluminum particles are added and stirred to enable antimony in the tin to react with aluminum to generate large-granular aluminum antimonide, the large-granular aluminum antimonide floats on the liquid tin, and a strainer is manually used to fish out carbon slag containing cuprous sulfide.
The method for removing arsenic, iron, copper, antimony and the like by refining crude tin has the following problems: the process is many, and the procedure is long, and the continuity operation is low between the process, and the direct rate of recovery of tin is low, and the manual work uses the strainer to drag for the sediment, and intensity of labour is big, and occupational health protection risk is high.
Disclosure of Invention
Based on the problems of the prior art, the utility model provides a slag dragging device for crude tin refining.
The utility model discloses a realize through following technical scheme:
a slag dragging device for crude tin refining comprises a tin refining pot, a stirrer and a slag dragging machine; the tin refining pot is a steel crude tin refining pot; the stirring machine is an electric integrated tin liquid stirring machine which is arranged on one side of the tin refining pot through a stirring machine mounting foot stand and can rotate up and down around a stirring machine rotating device to place or remove a stirring paddle into or out of a tin liquid layer in the tin refining pot and is driven by a stirring machine transmission motor;
the slag conveyor is arranged at the other side of the tin refining pot through a slag conveyor mounting foot stool, and can rotate up and down around a slag conveyor rotating system to place or move a scum inlet of the slag conveyor out of a scum layer of the tin refining pot, a slag conveyor transmission system is arranged at the rear end of a slag outlet of the slag conveyor, and a slag receiving container is arranged below the slag outlet of the slag conveyor.
Preferably, the slag conveyor is arranged obliquely.
The utility model also discloses a method for crude tin refining removes arsenic, iron, copper, antimony, the method has used foretell slag dragging device to arsenic, iron, copper, antimony in the liquid crude tin of three steps successively desorption in the refined pot of tin, and take out the charcoal sediment of dearsenifying, iron respectively, the sulphur sediment of decoppering, the aluminium sediment of deintontization specifically is:
the first step is as follows: removing arsenic and iron
1) Adding liquid crude tin to be subjected to impurity removal refining into a tin refining pot, and heating to a temperature required for removing arsenic and iron;
2) the stirring paddle is placed into a tin liquid layer in a tin refining pot to be stirred by a rotary stirring machine;
3) adding saw dust according to the arsenic and iron containing condition obtained by sampling and testing, wherein the total mass of the added saw dust is 1.0-1.2 times of the total mass of the arsenic and iron containing condition of the crude tin, slowly adding the saw dust for multiple times, so that the arsenic and the iron in the crude tin are adsorbed on the surface of the saw dust carbonized after being heated and float on the liquid crude tin;
4) rotating the slag conveyor, and placing a scum inlet of the slag conveyor into a scum layer in a tin refining pot; starting a slag conveyor, and fishing out carbon slag containing arsenic and iron into a slag receiving container;
5) slowly starting the stirring machine in the slag dragging process to enable the scum floating on the surface of the molten tin to move towards the inlet of the slag dragging machine; after the carbon slag is fished out, rotating the slag conveyor, moving the slag conveyor out of the tin refining pot, and replacing a slag receiving container;
the second step is that: copper removal
1) Adjusting the temperature of the liquid crude tin from which arsenic and iron are removed to the temperature required for removing copper; starting a stirring machine to stir;
2) adding sulfur according to the copper-containing condition obtained by sampling and testing, wherein the adding amount of the sulfur is 110-120% of the theoretical calculation value of Cu2S generated by all copper in the crude tin, so that the copper in the crude tin reacts with the sulfur to generate large-particle cuprous sulfide, and the cuprous sulfide floats on the liquid crude tin;
3) rotating the slag conveyor, and placing a scum inlet of the slag conveyor into a scum layer in a tin refining pot; starting a slag conveyor, and fishing out the sulfur slag containing cuprous sulfide into a slag receiving container;
4) slowly starting the stirring machine in the slag dragging process to enable the scum floating on the surface of the molten tin to move towards the inlet of the slag dragging machine; after the sulfur slag is fished out, rotating the slag conveyor, moving the slag conveyor out of the tin refining pot, and replacing a slag receiving container;
the third step: antimony removal
1) Adjusting the temperature of the liquid crude tin after copper removal to the temperature required by antimony removal; starting a stirring machine to stir;
2) according to the antimony-containing condition obtained by sampling and testing, adding aluminum particles according to the mass ratio of Sb to Al being 1:0.22-1, reacting antimony in the crude tin with aluminum to generate large-particle aluminum antimonide, and floating the large-particle aluminum antimonide out of the liquid tin;
3) rotating the slag conveyor, and placing a scum inlet of the slag conveyor into a scum layer in a tin refining pot; starting a slag conveyor, and fishing out the aluminum slag containing the aluminum antimonide into a slag receiving container;
4) slowly starting the stirring machine in the slag dragging process to enable the scum floating on the surface of the molten tin to move towards the inlet of the slag dragging machine; and after the aluminum slag is fished out, rotating the slag conveyor and the stirrer, moving the slag conveyor and the stirrer out of the tin refining pot, and replacing the slag receiving container.
Preferably, the temperature required for removing arsenic and iron is 280-300 ℃, the temperature required for removing copper is 300-320 ℃, and the temperature required for removing antimony is 380-400 ℃.
Preferably, the paddle is arranged at the center of the tin refining kettle.
Preferably, the method is to complete the removal of arsenic, iron, copper and antimony in the crude tin in the same tin refining kettle.
The utility model discloses following beneficial effect has at least:
1) the utility model adopts the slag fishing device to replace manual fishing of arsenic and iron removing carbon slag, copper removing sulfur slag and antimony removing aluminum slag, thereby reducing energy consumption, reducing labor intensity and occupational hazards of personnel and greatly improving working efficiency;
2) the utility model can remove arsenic, iron, copper and antimony in crude tin in the same tin refining pot, and has high heat utilization rate and low energy consumption;
3) the utility model provides a slag dragging machine slope sets up, and solid-state dross in the slag blanket is upwards taken out tin refining pot in proper order the inclined plane in succession, and wherein the liquid metallic tin that machinery mingled with flows back to tin refining pot naturally in the same direction as the inclined plane, and the sediment machinery of taking out presss from both sides miscellaneous tin low, and the direct rate of recovery of tin that gets into the refined tin is high.
Drawings
FIG. 1 is a schematic view of the apparatus of the present invention;
fig. 2 is a top view (partial) of fig. 1.
Detailed Description
Embodiments of the present invention will now be described with reference to the accompanying drawings. It will be appreciated by those skilled in the art that the following examples are illustrative of the invention only and should not be taken as limiting the scope of the invention. The specific techniques, connections, conditions, or the like, which are not specified in the examples, are performed according to the techniques, connections, conditions, or the like described in the literature in the art or according to the product specification. The materials, instruments or equipment are not indicated by manufacturers, and all the materials, instruments or equipment are conventional products which can be obtained by purchasing.
Referring to fig. 1 and 2, the slag dragging device for crude tin refining comprises a tin refining pot 1, a stirrer 2 and a slag dragging machine 3; the tin refining pot 1 is a steel crude tin refining pot; the stirrer 2 is an electric integrated tin liquid stirrer which is arranged on one side of the tin refining pot 1 through a stirrer mounting foot stand 8 and can rotate up and down around a stirrer rotating device 9 to place or move a stirring paddle 6 into or out of a tin liquid layer 4 in the tin refining pot through a stirrer driving motor 10; the slag conveyor 3 is an electric scraper type slag conveyor which is arranged at the other side of the tin refining pot 1 through a slag conveyor mounting foot rest 15 and can rotate up and down around a slag conveyor rotating system 14 to put a scum inlet 11 of the slag conveyor into or move the scum layer 5 of the tin refining pot, a slag conveyor transmission system 12 is arranged at the rear end of a slag outlet 13 of the slag conveyor, and a slag receiving container 7 is arranged below the slag outlet 13 of the slag conveyor. The slag dragging machine 3 is obliquely arranged, solid dross in the dross layer is upwards continuously dragged out of the tin refining pot along the inclined plane, liquid metal tin which is mechanically mixed naturally flows back into the tin refining pot along the inclined plane, the dragged-out slag has low mechanical mixed tin, and the direct recovery rate of tin entering refined tin is high.
The utility model provides a pair of method for refining arsenic removal, iron, copper, antimony of crude tin, used the foretell in the method drag for the sediment device to arsenic, iron, copper, antimony in the liquid crude tin of three steps successively desorption in same tin refining pot 1, and take out the charcoal sediment of dearsenifying, iron respectively, the sulphur sediment of decoppering, the aluminium sediment of antimony removal, the heat utilization rate is high, and the energy consumption is low, and concrete mode is as follows:
the first step is as follows: removing arsenic and iron
1) Adding liquid crude tin to be refined into tin refining pot 1, heating to the temperature required for removing arsenic and iron, wherein iron and arsenic preferentially generate large-particle Fe-As solid compounds, and Sn is generated if the crude tin contains more arsenic and less iron3As2Crystallizing and precipitating, otherwise generating Fe-Sn solid compounds and precipitating;
2) the stirring paddle 6 is placed into the tin liquid layer 4 in the tin refining pot to be stirred by the rotary stirring machine 2;
3) adding saw dust according to the arsenic and iron containing condition obtained by sampling and testing, wherein the total mass of the added saw dust is 1.0-1.2 times of the total mass of the arsenic and iron containing condition of the crude tin, slowly adding the saw dust for multiple times, so that the arsenic and the iron in the crude tin are adsorbed on the surface of the saw dust carbonized after being heated and float on the liquid crude tin;
4) rotating the slag conveyor 3, and placing a scum inlet 11 of the slag conveyor into a scum layer 5 in the tin refining pot 1; starting the slag conveyor 3, and fishing out the carbon slag containing arsenic and iron into the slag receiving container 7;
5) in the slag salvaging process, the stirring machine 2 is slowly started to lead the scum floating on the surface of the tin liquid to move to the inlet of the slag salvaging machine so as to be fished out as cleanly as possible; after the carbon slag is fished out, rotating the slag dragging machine 3, moving the slag dragging machine out of the tin refining pot 1 and replacing the slag receiving container 7;
the second step is that: copper removal
1) Adjusting the temperature of the liquid crude tin after removing arsenic and iron to the temperature required for removing copper, and in the temperature range, generating Cu from copper and sulfur2S particles float on the surface of the liquid tin; starting the stirring machine 2 for stirring;
2) adding sulfur according to the copper-containing condition obtained by sampling and testing, wherein the adding amount of sulfur is that Cu is generated from all copper in crude tin2The theoretical calculated value of S is 110-120%, so that copper in the crude tin reacts with sulfur to generate large-particle cuprous sulfide which floats on the liquid crude tin;
3) rotating the slag conveyor 3, and placing a scum inlet 11 of the slag conveyor into a scum layer 5 in the tin refining pot 1; starting the slag conveyor 3, and fishing out the sulfur slag containing cuprous sulfide into a slag receiving container 7;
4) in the slag salvaging process, the stirring machine 2 is slowly started to lead the scum floating on the surface of the tin liquid to move to the inlet of the slag salvaging machine so as to be fished out as cleanly as possible; after the sulfur slag is fished out, rotating the slag conveyor 3, moving the slag conveyor out of the tin refining pot 1, and replacing the slag receiving container 7;
the third step: antimony removal
1) Adjusting the temperature of the liquid crude tin after copper removal to the temperature required for removing antimony, wherein within the temperature range, antimony and aluminum generate AlSb compounds with high melting points to form aluminum slag floating in the liquid tin; starting the stirring machine 2 for stirring;
2) according to the antimony-containing condition obtained by sampling and testing, adding aluminum particles according to the mass ratio of Sb to Al being 1:0.22-1, reacting antimony in the crude tin with aluminum to generate large-particle aluminum antimonide, and floating the large-particle aluminum antimonide out of the liquid tin;
3) rotating the slag conveyor 3, and placing a scum inlet 11 of the slag conveyor into a scum layer 5 in the tin refining pot 1; starting the slag conveyor 3, fishing out the aluminum slag containing the aluminum antimonide into the slag receiving container 7;
4) in the slag salvaging process, the stirring machine 2 is slowly started to lead the scum floating on the surface of the tin liquid to move to the inlet of the slag salvaging machine so as to be fished out as cleanly as possible; and after the aluminum slag is fished out, rotating the slag conveyor 3 and the stirrer 2, moving the slag conveyor 3 and the stirrer 2 out of the tin refining pot 1, and replacing the slag receiving container 7. The stirring paddle 6 is arranged at the center of the tin refining pot 1, and the stirring paddle 6 rotates along one direction, so that the molten tin and the scum on the surface can also rotate in the same direction.
Further, the temperature required for removing arsenic and iron is 280-300 ℃, the temperature required for removing copper is 300-320 ℃, and the temperature required for removing antimony is 380-400 ℃.
The utility model can remove arsenic, iron, copper and antimony in the crude tin in the same tin refining pot 1, and then respectively fishing out carbon slag, sulfur slag and aluminum slag for the corresponding next working procedure treatment; removing arsenic, iron, copper and antimony, and then refining tin, and removing lead and bismuth by an electrothermal mechanical crystallizer or a vacuum furnace in the next procedure to obtain refined tin.
Example (b):
30 tons of crude tin with the main components of Sn 95.68%, Fe 0.65%, As 0.47%, Cu0.20%, Sb 0.68%, Pb 1.19% and Bi 0.05% is added into the tin refining pot of the device. The stirring paddle is arranged at the center of the tin refining pot and rotates along one direction, so that the molten tin and the scum on the surface can rotate in the same direction.
The first step is as follows: removing arsenic and iron
The total mass of 30 tons of crude tin containing arsenic and iron is 0.336 tons calculated according to the total mass of Fe 0.65% and As 0.47%, and about 0.370 tons of sawdust is needed when the total mass of the added sawdust is 1.1 times of the total mass of the crude tin containing arsenic and iron.
Heating the crude tin to 290 ℃, and putting a stirring paddle into a tin liquid layer in a tin refining pot by a rotary stirrer for stirring. Slowly adding 0.370 ton of sawdust into the stirring tank for multiple times, so that arsenic and iron in the crude tin are adsorbed on the surface of the sawdust carbonized after being heated and float on the liquid crude tin; rotating the slag conveyor, and placing a scum inlet of the slag conveyor into a scum layer in a tin refining pot; starting a slag conveyor, and fishing out carbon slag containing arsenic and iron into a slag receiving container; in the slag salvaging process, the stirring machine is slowly started to lead the scum floating on the surface of the tin liquid to move to the inlet of the slag salvaging machine so as to be fished out as cleanly as possible; and after the carbon slag is fished out, rotating the slag dragging machine, moving the slag dragging machine out of the tin refining pot, and replacing the slag receiving container.
The second step is that: copper removal
Calculating the copper content of 30 tons of crude tin according to the content of Cu0.20 percent to obtain 0.06 ton of copper, and generating Cu according to the total copper in the crude tin2The theoretical calculation value of S is that 0.015 ton of sulfur is needed, and about 0.018 ton of sulfur is needed according to the addition of 120 percent.
Adjusting the temperature of the liquid crude tin after removing arsenic and iron to 300 ℃, starting a stirring machine to stir, and slowly adding 0.018 ton of sulfur to ensure that copper and sulfur generate large-particle Cu2S particles float on the surface of the liquid tin; rotating the slag conveyor, and placing a scum inlet of the slag conveyor into a scum layer in a tin refining pot; and starting the slag conveyor, and fishing out the sulfur slag containing the cuprous sulfide into a slag receiving container. In the slag salvaging process, the stirring machine is slowly started to lead the scum floating on the surface of the tin liquid to move to the inlet of the slag salvaging machine so as to be fished out as cleanly as possible; and after the sulfur slag is fished out, rotating the slag conveyor, moving the slag conveyor out of the tin refining pot, and replacing the slag receiving container.
The third step: antimony removal
Calculated according to the content of Sb of 0.68%, the content of 30 tons of crude tin and copper is 0.204 tons, and about 0.122 ton of aluminum particles is needed to be added according to the mass ratio of Sb to Al of 1: 0.6.
Adjusting the temperature of the liquid crude tin after copper removal to 390 ℃, slowly adding 0.122 ton of aluminum particles, starting a stirring machine to stir, reacting antimony in the crude tin with aluminum to generate large-particle aluminum antimonide, and floating the large-particle aluminum antimonide out of the liquid tin; rotating the slag conveyor, and placing a scum inlet of the slag conveyor into a scum layer in a tin refining pot; and starting the slag conveyor to fish out the aluminum slag containing the aluminum antimonide into a slag receiving container. In the slag salvaging process, the stirring machine is slowly started to lead the scum floating on the surface of the tin liquid to move to the inlet of the slag salvaging machine so as to be fished out as cleanly as possible; and after the aluminum slag is fished out, rotating the slag conveyor and the stirrer, moving the slag conveyor and the stirrer out of the tin refining pot, and replacing the slag receiving container.
Removing arsenic, iron, copper and antimony in the crude tin, fishing out carbon slag, sulfur slag and aluminum slag respectively in sequence, and carrying out corresponding next working procedure treatment; removing arsenic, iron, copper and antimony, and then refining tin, and removing lead and bismuth by an electrothermal mechanical crystallizer or a vacuum furnace in the next procedure to obtain refined tin.
The above disclosure is only for the purpose of illustrating the preferred embodiments of the present invention and is not intended to limit the scope of the invention, which is defined by the appended claims.
Claims (3)
1. The utility model provides a slag dragging device of crude tin refining which characterized in that: the device consists of a tin refining pot (1), a stirrer (2) and a slag conveyor (3);
the tin refining pot (1) is a steel crude tin refining pot;
the stirrer (2) is an electric integrated tin liquid stirrer which is arranged on one side of the tin refining pot (1) through a stirrer mounting foot stand (8) and can rotate up and down around a stirrer rotating device (9) to place or remove the stirring paddle (6) into or out of a tin liquid layer (4) in the tin refining pot through the stirring paddle transmission motor (10);
the slag conveyor (3) is arranged at the other side of the tin refining pot (1) through a slag conveyor mounting foot stand (15), and can rotate up and down around a slag conveyor rotating system (14) to place or move a slag conveyor scum inlet (11) into or out of an electric scraper type slag conveyor of a tin refining pot scum layer (5), a slag conveyor transmission system (12) is arranged at the rear end of a slag conveyor slag outlet (13), and a slag receiving container (7) is arranged below the slag conveyor slag outlet (13).
2. The dross scooping device of claim 1, wherein: the slag conveyor (3) is obliquely arranged.
3. The dross scooping device of claim 1, wherein: the stirring paddle (6) is arranged at the center of the tin refining pot (1).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021182746.6U CN212451580U (en) | 2020-06-23 | 2020-06-23 | Slag dragging device for crude tin refining |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021182746.6U CN212451580U (en) | 2020-06-23 | 2020-06-23 | Slag dragging device for crude tin refining |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN212451580U true CN212451580U (en) | 2021-02-02 |
Family
ID=74462301
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202021182746.6U Active CN212451580U (en) | 2020-06-23 | 2020-06-23 | Slag dragging device for crude tin refining |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN212451580U (en) |
-
2020
- 2020-06-23 CN CN202021182746.6U patent/CN212451580U/en active Active
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN105803213B (en) | The method that bismuth is refined from slag bismuth oxide | |
| CN111519041A (en) | Crude tin refining slag-dragging device and method for removing arsenic, iron, copper and antimony in crude tin refining | |
| EP2203573A1 (en) | Recovery of residues containing copper and other valuable metals | |
| CN105063369B (en) | A kind of copper removal compositions and its application for reviver refining | |
| JP7524199B2 (en) | Improved tin production | |
| CN212451580U (en) | Slag dragging device for crude tin refining | |
| CN1133752C (en) | Direct zinc sulfide concentrate leaching-out process with coupled synergic leaching-out and solvent extraction and separation | |
| JP2017066464A (en) | Floatation separation method of silver and lead | |
| CN1233857C (en) | Decoppering refining agent in use for fire refining of non-ferrous metal with low melting point and technical procedure | |
| CN112143915B (en) | Tin refining nickel removing process and device | |
| Wen et al. | Rapid removal of copper impurity from bismuth-copper alloy melts via super-gravity separation | |
| JP7534305B2 (en) | Improved simultaneous production of lead and tin products | |
| Wang et al. | A crystallization method with significant industrial potential for the separation and enrichment of silver from crude lead | |
| EP0007890B1 (en) | A method of manufacturing and refining crude lead from arsenic-containing lead raw-materials | |
| JPH04224639A (en) | Method for purification of lead wherein copper is especially removed | |
| US2109144A (en) | Process of treating metal | |
| JP3424885B2 (en) | Copper electrolytic slime treatment method | |
| JP2587814B2 (en) | Method for treating concentrate from copper converter | |
| US2043573A (en) | Process for recovering tin | |
| RU2780328C1 (en) | Advanced production of tin including a composition containing tin, lead, silver, and antimony | |
| US4427629A (en) | Process for metal-enrichment of lead bullion | |
| US5108497A (en) | Treatment of indium dusts | |
| CN115305370B (en) | Copper-tin-nickel brazing filler metal prepared by utilizing electronic waste recovered alloy, method and system | |
| RU2786016C1 (en) | Improved method for production of high-pure lead | |
| CA1337579C (en) | Method for the refining of lead |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |