US2825644A - Process of removing lead from copper base alloys - Google Patents
Process of removing lead from copper base alloys Download PDFInfo
- Publication number
- US2825644A US2825644A US406886A US40688654A US2825644A US 2825644 A US2825644 A US 2825644A US 406886 A US406886 A US 406886A US 40688654 A US40688654 A US 40688654A US 2825644 A US2825644 A US 2825644A
- Authority
- US
- United States
- Prior art keywords
- lead
- copper base
- nitric acid
- copper
- solution
- 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.)
- Expired - Lifetime
Links
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 title claims description 26
- 229910052802 copper Inorganic materials 0.000 title claims description 26
- 239000010949 copper Substances 0.000 title claims description 26
- 229910045601 alloy Inorganic materials 0.000 title claims description 25
- 239000000956 alloy Substances 0.000 title claims description 25
- 238000000034 method Methods 0.000 title claims description 20
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 21
- 229910017604 nitric acid Inorganic materials 0.000 claims description 21
- 239000002245 particle Substances 0.000 claims description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 6
- 239000003153 chemical reaction reagent Substances 0.000 claims description 4
- 239000000243 solution Substances 0.000 description 18
- 238000007514 turning Methods 0.000 description 11
- 229910000906 Bronze Inorganic materials 0.000 description 8
- 239000010974 bronze Substances 0.000 description 8
- KUNSUQLRTQLHQQ-UHFFFAOYSA-N copper tin Chemical group [Cu].[Sn] KUNSUQLRTQLHQQ-UHFFFAOYSA-N 0.000 description 8
- 239000000463 material Substances 0.000 description 6
- 239000002253 acid Substances 0.000 description 5
- 229910001369 Brass Inorganic materials 0.000 description 4
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 4
- 239000010951 brass Substances 0.000 description 4
- 238000000227 grinding Methods 0.000 description 4
- 239000011701 zinc Substances 0.000 description 4
- 229910052725 zinc Inorganic materials 0.000 description 4
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 3
- 230000008901 benefit Effects 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 3
- 239000000470 constituent Substances 0.000 description 3
- 230000008030 elimination Effects 0.000 description 3
- 238000003379 elimination reaction Methods 0.000 description 3
- 239000004519 grease Substances 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 229910000881 Cu alloy Inorganic materials 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 1
- 241000272201 Columbiformes Species 0.000 description 1
- 235000011941 Tilia x europaea Nutrition 0.000 description 1
- 238000013019 agitation Methods 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 150000001879 copper Chemical class 0.000 description 1
- 210000004087 cornea Anatomy 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000005238 degreasing Methods 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 229910000765 intermetallic Inorganic materials 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 150000002611 lead compounds Chemical class 0.000 description 1
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 1
- 239000004571 lime Substances 0.000 description 1
- 229910001092 metal group alloy Inorganic materials 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B15/00—Obtaining copper
- C22B15/0002—Preliminary treatment
- C22B15/0004—Preliminary treatment without modification of the copper constituent
- C22B15/0008—Preliminary treatment without modification of the copper constituent by wet processes
Definitions
- the present invention relates to the process of removing lead from finely divided copper base alloys such as turnings and grindings.
- a purpose-of the invention is to remove lead from finely divided scrap of copper base alloys so as to permit the scrap to be remelted in order to produce ingots which are relatively low in lead.
- QA further purpose is to eliminate lead from particles of copper base alloy by treatment with nitric acid as substantially the only reagent, thus minimizing the solution of copper and other ingredients, operating preferably at room temperature and in a concentration range of 2 to 13 percent of concentrated nitric acid in Water by volume.
- a further purpose is to employ a counter current treatment of the particles of copper base alloy, first with weak nitric acid and then with stronger nitric acid.
- a further purpose is to degrease the particles of copper base alloy, prior to treatment with the nitric acid.
- a further purpose is to agitate the nitric acid and the copper base alloy particles during the treatment.
- a further purpose is to recover the lead from the solution by precipitation.
- Metallic alloys are essentially composed of metallic crystals, solid solutions and intermetallic compounds. The differences between these various constituents are readily recognizable under the microscope. It is thus theoretically possible to eliminate a certain constituent by a wet process, treating the alloy with a reagent which is capable of dissolving the desired constituent without attacking the rest of the alloy.
- Lead is of course practically insoluble in copper alloy in the solid state, and it appears as a distinct phase in aren t F 2 the micro-structure of bronze and brass. The elimination of lead by a wet process is then possible in alloys which are sufiiciently finely divided to be attacked in depth.
- lead is removed from copper alloys and particularly finely divided copper base alloys such as turnings and grindings of brass and bronze, by a reaction with nitric acid alone.
- Nitric acid is in the present process the only reactant.
- nitric acid not only attacks lead. but also attacks copper and zinc, and is used in analytical laboratories to dissolve bronze and brass, it will be appreciated that the use of nitric acid alone to dissolve lead from a copper base alloy is very remarkable.
- the present inventor has discovered that by observing certain precautions as indicated herein, it is possible to eliminate the lead without dissolving the slightest trace of copper.
- the process of the present invention has the advantage that the price is low. Another great advantage of the present process is that operation is possible at ambient temperature and in fact is preferably carried on at such temperatures. Thus, a better result is obtained than by previous processes, using a very simple installation and at low cost.
- concentration of the acid to be employed depends in part upon the material to be treated. Generally speaking, good results have been obtained, using concentrations of from 2 to 13 percent of nitric acid in water by volume. Higher concentrations are preferably used at lower temperatures (below 20 C.) and lower concentrations are preferably used at higher temperatures such asare encountered in summer.
- a simple means of mixing is to carry out the process in a rotating drum containing the finely divided copper base alloy.
- the drum can be constructed of wood which is quite resistant to the treatment.
- the lead will be more or less completely removed. On the average to percent by weight of the lead content is eliminated when ordinary turnings of brass or bronze are used, and percent by weight is eliminated from grindings or very fine turnings.
- the solution containing the lead can be neutralized, for example by lime or by a carbonate, and the total quantity of lead is then recovered as a hydroxide or carbonate substantially free from other .7 2,825,644 p a r metals.
- the appropriate lead compound is easily reduced to metallic lead.
- the process of removing lead from finely divided copper base alloys which comprises treating the particles of copper base alloy with a water solution of 2 to 13% of nitric acid by volume in which nitric acid is the only reagent present.
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacture And Refinement Of Metals (AREA)
Description
rRocEss or REMOVING LEAD FRoM cornea BASE ALLOYS Paul Kemp, Bois Colombes, France No Drawing. Application January 23, 1954 Serial No. 406,886
Claims. (Cl. 7512i The present invention relates to the process of removing lead from finely divided copper base alloys such as turnings and grindings.
. A purpose-of the invention is to remove lead from finely divided scrap of copper base alloys so as to permit the scrap to be remelted in order to produce ingots which are relatively low in lead.
QA further purpose is to eliminate lead from particles of copper base alloy by treatment with nitric acid as substantially the only reagent, thus minimizing the solution of copper and other ingredients, operating preferably at room temperature and in a concentration range of 2 to 13 percent of concentrated nitric acid in Water by volume.
A further purpose is to employ a counter current treatment of the particles of copper base alloy, first with weak nitric acid and then with stronger nitric acid.
A further purpose is to degrease the particles of copper base alloy, prior to treatment with the nitric acid.
A further purpose is to agitate the nitric acid and the copper base alloy particles during the treatment.
A further purpose is to recover the lead from the solution by precipitation.
Further purposes appear in the specification and in the claims.
The removal of undesirable elements from alloys is usually accomplished by fusion of the alloy, followed in some cases by oxidation or volatilization of elements to be eliminated. In other cases, fractional solidification is employedto eliminate undesired elements, which are concentrated in one of the fractions obtained. In still other T instances, substances areadded with which the base alloying material forms insoluble compounds. I
It is not always possible however to employ therma processes. Aluminum, zinc or iron can be removed from copper base alloys by one of these methods, but it is not possible at the present time to decrease the lead content even to a slight extent without at the same time losing a large part of the tin.
The elimination of lead from such alloys is, however, an important problem when it is considered that many specifications for bronzes of high quality permit very small lead contents. It has, therefore, in many cases been necessary to make such high quality bronzes from virgin copper and tin. The use of secondary bronze from scrap has not been permitted because such material has too high a content of lead. It is therefore necessary to find some other process to solve this problem.
Metallic alloys are essentially composed of metallic crystals, solid solutions and intermetallic compounds. The differences between these various constituents are readily recognizable under the microscope. It is thus theoretically possible to eliminate a certain constituent by a wet process, treating the alloy with a reagent which is capable of dissolving the desired constituent without attacking the rest of the alloy.
Lead is of course practically insoluble in copper alloy in the solid state, and it appears as a distinct phase in aren t F 2 the micro-structure of bronze and brass. The elimination of lead by a wet process is then possible in alloys which are sufiiciently finely divided to be attacked in depth.
it has already been proposed to employ certain organic compounds such as tartarates or citric acid in combination with nitric acid to remove lead from grindings or turnings of bronze. This process has not been satisfactory, and in any case it is necessary to have an apparatus having a lining of special material and to operate at a temperature of about 100 C.
Lead has also been eliminated by double decomposition with salts of copper in acid solution. Such copper salts are relatively expensive. Copper deposits on the material under treatment in the course of the reaction and to a certain extent retards the penetration of the reacting materials into the interior.
In accordance with the presentinvention, lead is removed from copper alloys and particularly finely divided copper base alloys such as turnings and grindings of brass and bronze, by a reaction with nitric acid alone. l
Nitric acid is in the present process the only reactant. When one realizes that nitric acid not only attacks lead. but also attacks copper and zinc, and is used in analytical laboratories to dissolve bronze and brass, it will be appreciated that the use of nitric acid alone to dissolve lead from a copper base alloy is very remarkable. The present inventor has discovered that by observing certain precautions as indicated herein, it is possible to eliminate the lead without dissolving the slightest trace of copper.
The process of the present invention has the advantage that the price is low. Another great advantage of the present process is that operation is possible at ambient temperature and in fact is preferably carried on at such temperatures. Thus, a better result is obtained than by previous processes, using a very simple installation and at low cost.
The concentration of the acid to be employed depends in part upon the material to be treated. Generally speaking, good results have been obtained, using concentrations of from 2 to 13 percent of nitric acid in water by volume. Higher concentrations are preferably used at lower temperatures (below 20 C.) and lower concentrations are preferably used at higher temperatures such asare encountered in summer.
It is preferable to start out a deleading operation using an acid which has previously been used in'deleading an. earlier charge. The last residual'content'of lead is pref -J. erably eliminated by fresh and more concentrated nitric": acid.
Bronze turnings in practice almost always are coated with oil or grease. It has been found that the elimination of lead can be accomplished most effectively if the turnings have previously been subjected to a treatment which removes this grease coating suitably by heating above the point of decomposition of the grease, or by degreasing the turnings with a solvent.
in order to secure a rapid and complete reaction, it is desirable to mix the turnings intimately with the acid. A simple means of mixing is to carry out the process in a rotating drum containing the finely divided copper base alloy. The drum can be constructed of wood which is quite resistant to the treatment.
Depending upon the nature of the copper base alloy particles, the lead will be more or less completely removed. On the average to percent by weight of the lead content is eliminated when ordinary turnings of brass or bronze are used, and percent by weight is eliminated from grindings or very fine turnings.
To recover the lead, the solution containing the lead can be neutralized, for example by lime or by a carbonate, and the total quantity of lead is then recovered as a hydroxide or carbonate substantially free from other .7 2,825,644 p a r metals. The appropriate lead compound is easily reduced to metallic lead.
7 Example I .lQOO-kilograms of bronzeturnings of the following composition byweight: r
are charged into a rotating drum which is filled with a mixture of 640 liters of water and 60 liters of concentrated are treatediwith the leaded solution remaining from the treatment of Example I. Thetreatment with this solution is continued for30 minutes, and then the solution is emptied, at which time it contains 85 grams of lead per liter.- The drum is thenv charged with a new solution of i 4 i 160 kilograms of lead were recovered by precipitation'in the form of hydroxide. It will be evident that the process of the invention has wide application particularly in secondary copper refining nitric acid. The drum is turned for 90minutes at a temperature'of 1 8-C and the solution is then emptied. The solution when emptied'co'ntains 50 grams of lead per liter. The" t u nings after the treatment have the. following analysisby weight Percent Tin." "6.9 Copper '87.? Lead V 1.0 Zinc 4.2
The recovery from thetreatment amounts to 964 kilograms of alloy. V p
. a Example 11 .1000 kilograms of leaded bronze tnrnings of the followins a y s by weight;
- 1 Percent Tin V j 7.5 Copper 75.8
Lead 7 14.7,
' Zinc 1.8
640 liters'of water and 60 liters of nitric acid. This new solution is usedl to treat the turnings'with agitation in the drumior 'oneihour; after which. the. new solution is re- 7 moved and theturnings are dried. The recovery of turnings is 870 kilograms havingthe following composition byweight: v
From the two solutions obtained from this example,
especially to produce secondary ingots of precise analysis.
in view of my invention and disclosure variations and modifications to meet individual whim or particular need will doubtless become evident to others skilled in the art, to obtain all or part of the benefits of my invention without copying the process shown, and I, therefore, claim all such insofar as they fallwithin the reasonable spirit and scope of my claims.
Having thus described my invention what I claim as new and desire to secure by Letters Patent is:
l. The process of removing lead from finely divided copper base alloys, which comprises treating the particles of copper base alloy with a water solution of 2 to 13% of nitric acid by volume in which nitric acid is the only reagent present.
2.. The process of claim 1, in which the treatment is at ambient temperature.
7 3. Theprocess of claim 1, in which the. treatment is carried on first with partiallyspent nitric acid solution and then with a stronger concentration of nitric acid solution.
4. The process, of claim 1, in which the particles of copper base alloy, and the nitric acid during treatment.
5. The process of claim 1, in which the lead is subse-. quently recovered from the. solution'by precipitating as a salt of the class consisting of a hydroxide and a carbonate.
solution are. agitated References Cited 'inthe file of thisrpatent UNITED STATES PATENTS .l, 192 ,945 SherWo'od' Aug. 1, 1916' 1,051,683 France Sept. 16, 1953 OTHER REFERENCES American, Society for Metals; Cleveland, Ohio.' Page
Claims (1)
1. THE PROCESS OF REMOVING LEAD FROM FINELY DIVIDED COPPER BASE ALLOYS, WHICH COMPRISES TREATING THE PARTICLES OF COPPER BASE ALLOY WITH A WATER SOLUTION OF 2 TO 13% OF NITRIC ACID BY VOLUME IN WHICH NITRIC ACID IS THE ONLY REAGENT PRESENT.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US406886A US2825644A (en) | 1954-01-28 | 1954-01-28 | Process of removing lead from copper base alloys |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US406886A US2825644A (en) | 1954-01-28 | 1954-01-28 | Process of removing lead from copper base alloys |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US2825644A true US2825644A (en) | 1958-03-04 |
Family
ID=23609773
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US406886A Expired - Lifetime US2825644A (en) | 1954-01-28 | 1954-01-28 | Process of removing lead from copper base alloys |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US2825644A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IT201800008041A1 (en) * | 2018-08-10 | 2020-02-10 | Almag Spa Azienda Lavorazioni Metallurgiche Ed Affini Gnutti | PROCESS FOR OBTAINING A BRASS BILLET WITH A REDUCED LEAD CONTENT AND A BILLET SO OBTAINED |
| RU2811934C2 (en) * | 2018-08-10 | 2024-01-18 | А.Л.М.А.Г. С.П.А. Ацьенда Лаворацьони Металлурджике Эд Аффини Ньютти | Method for producing brass billet with reduced lead content and billet |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1192945A (en) * | 1913-09-24 | 1916-08-01 | Albert H Sherwood | Process of separating metals. |
| US1375930A (en) * | 1920-01-02 | 1921-04-26 | Oliver C Ralston | Process of treating brass scrap |
| US1643922A (en) * | 1924-03-10 | 1927-09-27 | Niels C Christensen | Process of precipitating copper from sulphate solution |
| US1918817A (en) * | 1928-12-12 | 1933-07-18 | Dudzeele Corp | Art of removing lead from tubes and other articles |
| US2342733A (en) * | 1940-09-12 | 1944-02-29 | Guyard Leon Jean Baptiste | Method for purifying bismuth |
| FR1051683A (en) * | 1952-02-19 | 1954-01-18 | Improvements in wet refining processes for metals and non-ferrous metal alloys |
-
1954
- 1954-01-28 US US406886A patent/US2825644A/en not_active Expired - Lifetime
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1192945A (en) * | 1913-09-24 | 1916-08-01 | Albert H Sherwood | Process of separating metals. |
| US1375930A (en) * | 1920-01-02 | 1921-04-26 | Oliver C Ralston | Process of treating brass scrap |
| US1643922A (en) * | 1924-03-10 | 1927-09-27 | Niels C Christensen | Process of precipitating copper from sulphate solution |
| US1918817A (en) * | 1928-12-12 | 1933-07-18 | Dudzeele Corp | Art of removing lead from tubes and other articles |
| US2342733A (en) * | 1940-09-12 | 1944-02-29 | Guyard Leon Jean Baptiste | Method for purifying bismuth |
| FR1051683A (en) * | 1952-02-19 | 1954-01-18 | Improvements in wet refining processes for metals and non-ferrous metal alloys |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IT201800008041A1 (en) * | 2018-08-10 | 2020-02-10 | Almag Spa Azienda Lavorazioni Metallurgiche Ed Affini Gnutti | PROCESS FOR OBTAINING A BRASS BILLET WITH A REDUCED LEAD CONTENT AND A BILLET SO OBTAINED |
| WO2020031060A1 (en) * | 2018-08-10 | 2020-02-13 | A.L.M.A.G. S.P.A. Azienda Lavorazioni Metallurgiche Ed Affini Gnutti | Method for obtaining a brass billet with reduced lead content and the billet thus obtained |
| CN112703261A (en) * | 2018-08-10 | 2021-04-23 | A.L.M.A.G.金属和成品加工股份公司 | Method for obtaining a brass ingot with reduced lead content and ingot thus obtained |
| US20210291268A1 (en) * | 2018-08-10 | 2021-09-23 | A.L.M.A.G. S.P.A. Azienda Lavorazioni Metallurgiche Ed Affini Gnutti | Method for obtaining a brass billet with reduced lead content and the billet thus obtained |
| JP2022502563A (en) * | 2018-08-10 | 2022-01-11 | アルマグ・ソチエタ・ペル・アツィオーニ・アツィエンダ・ラヴォラツィオーニ・メタッルールジケ・エド・アッフィーニ・ニュッティA.L.M.A.G. S.P.A. Azienda Lavorazioni Metallurgiche Ed Affini Gnutti | A method for obtaining a brass billet with a reduced lead content and a billet obtained by the method. |
| CN112703261B (en) * | 2018-08-10 | 2022-08-16 | A.L.M.A.G.金属和成品加工股份公司 | Method for obtaining a brass ingot with reduced lead content and ingot thus obtained |
| TWI780351B (en) * | 2018-08-10 | 2022-10-11 | 義大利商阿爾瑪格股份有限公司 | Method for obtaining a brass billet with reduced lead content |
| RU2811934C2 (en) * | 2018-08-10 | 2024-01-18 | А.Л.М.А.Г. С.П.А. Ацьенда Лаворацьони Металлурджике Эд Аффини Ньютти | Method for producing brass billet with reduced lead content and billet |
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