EP0512247A2 - Method for leaching gold and silver - Google Patents
Method for leaching gold and silver Download PDFInfo
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- EP0512247A2 EP0512247A2 EP92105566A EP92105566A EP0512247A2 EP 0512247 A2 EP0512247 A2 EP 0512247A2 EP 92105566 A EP92105566 A EP 92105566A EP 92105566 A EP92105566 A EP 92105566A EP 0512247 A2 EP0512247 A2 EP 0512247A2
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- leaching
- peroxoborate
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- 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
- C22B11/00—Obtaining noble metals
- C22B11/08—Obtaining noble metals by cyaniding
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- the invention relates to a method for leaching gold and silver from ores, ore concentrates and mining material from previous incomplete leachings by grinding the material to be leached in the presence of a cyanide leaching solution which has a pH of 8 to 13 and contains a peroxo compound.
- heap leaching the ore that has been broken down to 10 to 50 mm is piled up and sprinkled with an aqueous cyanide solution;
- aqueous cyanide solution usually atmospheric oxygen is used as the oxidizing agent, but peroxo compounds can also be added to the ore heap or the leaching solution - DE-PS 38 30 703, DE-patent application P 40 17 899.4, GB-A 2219474.
- stirring leaching finely ground ore is leached in tanks or other containers.
- the gold yield rate is higher here than in the case of heap leaching, but the process costs are also significantly higher.
- the stirring leaching requires an average grinding of the ore to be leached to less than 100 ⁇ m; Usually a degree of grinding is required, according to which at least 80% of the ground material is smaller than 45 ⁇ m.
- Known discontinuously and continuously operating wet mills are used to grind the ore.
- the grinding takes place in one, but mostly in two or more stages, the oversize being recycled in each case.
- the resulting slurry from the ground ore and generally water is mixed with cyanide and possibly other leaching chemicals and then fed to the leaching tanks.
- the leaching time for fumigation with air is usually 15 to 30 hours, but it could be significantly shortened by using peroxo compounds, such as hydrogen peroxide, calcium peroxide or peroxoborates, instead of or in addition to air fumigation - DE-PS 36 37 082, DE- PS 38 30 703, DE patent application P 40 17 899.4.
- peroxo compounds such as hydrogen peroxide, calcium peroxide or peroxoborates
- the object of the invention is to improve the "cyanidation-in-mill" technique in such a way that an even higher gold yield can be achieved compared to the use of hydrogen peroxide. It should be possible not only to further shorten the total leaching time - time required for grinding and the subsequent stirring leaching - with a high gold yield, but also, if possible, to do without the stirring leaching.
- the object is achieved by a process for the leaching of gold and silver from ores, ore concentrates and mining material by grinding the material to be leached in the presence of a cyanide leaching solution which has a pH of 8 to 13 and contains a peroxo compound, characterized in that at least one peroxoborate compound is present as the peroxo compound.
- an effective amount of peroxoborate is present in dissolved and / or finely divided form.
- the total amount of peroxoborate required can be present in the mill at the start of the leaching, or the peroxoborate is added in one or more portions during the leaching, for example before each grinding stage of a multi-stage grinding process, or is formed in situ from an added borate and hydrogen peroxide .
- the addition of a peroxoborate is preferred over the in situ formation in the leach slurry.
- the peroxoborate can be added in powder form, as an aqueous solution or suspension to the material to be leached, the cyanide leaching solution or the leaching slurry.
- peroxoborate which strongly depends on the material to be leached, can easily be determined on the basis of preliminary experiments. Per t of the material to be leached, 1 to 100 equivalents of peroxoborate, calculated as BO3-, will generally be sufficient. The requirement is preferably between 10 and 60 equivalents of peroxoborate.
- active oxygen compound peroxoborates or the hydrogen peroxide formed by hydrolysis split off oxygen; oxygen, hydrogen peroxide and peroxoborate can act as oxidizing agents in the leaching process.
- Peroxoborates including their hydrates, are those of the alkali and alkaline earth metals, but in principle also peroxoborates of other metals, such as, for. B. Zinc.
- the commercially available peroxoborates namely the so-called sodium perborate mono- and tetrahydrate and calcium perborate, can be used particularly advantageously.
- So-called superoxidized peroxoborates such as are known from DE-OS 28 11 554 and DE-OS 35 05 158, can also be used.
- the leaching in the mill is carried out at a pH of 8 to 13, preferably 9 to 12.
- the pH is adjusted in a manner known per se using alkalis, such as, in particular, lime milk and sodium hydroxide solution. During the grinding process, it may be advisable to adjust the pH to values recognized as optimal.
- the cyanide content, calculated as CN, in the leaching solution will usually be between 0.005 and 2.5% by weight. Cyanide contents between 0.02 and 0.2% by weight are preferred. Cyanide is used as an alkali cyanide, in particular sodium cyanide, or as calcium cyanide, for example in the form of the so-called "black cyanide".
- the cyanide can be added in solid or dissolved form to an aqueous slurry containing the material to be leached, or a cyanide-containing leaching solution is used directly to prepare the leaching slurry.
- Known wet grinding units are suitable for leaching according to the invention; Ball mills and bar mills are preferred.
- the grinding time depends on the material to be leached and the desired degree of extraction. It is usually milled between 15 minutes and 2 hours.
- the solids concentration of the leach sludge during grinding can vary over a wide range, usually between 25 and 60% by weight.
- the degree of grinding is in the range that is customary for stirring leaching.
- the leaching sludge can, if necessary, be subjected to a stirring leaching or pressure leaching in order to further increase the degree of extraction. Otherwise, the precious metal cyanocomplexes present in solution in the leaching slurry are used for further precious metal extraction by known process stages - the carbon-in-pulp (CIP) and resin-in-pulp (RIP) process and the Merrill-Crowe process separated.
- CIP carbon-in-pulp
- RIP resin-in-pulp
- peroxoborate is all the more surprising given that other peroxo compounds, including calcium peroxide, sodium percarbonate and ammonium peroxodisulfate, have been found to be less effective in terms of gold yield than hydrogen peroxide.
- the leaching tests using the "cyanidation-in-mill” technique were carried out in a rod mill made of stainless steel with a total volume of 4.5 l. 12 stainless steel rods (18.2 cm long, 2.5 cm diameter) were used as grinding media, thus filling 24% of the mill volume.
- the grindings were each carried out with 400 g of ore and 600 g of water (40% solids). The volume of the resulting ore slurry fills a further 16% of the mill, so that the total filling of the mill is 40%.
- the various oxidizing agents and the lime were added to the mill at the beginning of the grinding.
- the gold yield - leached gold, based on the total Au content of the ore -, the O2 content (ppm) in the leaching solution - determined using an O2 electrode - and the cyanide consumption (kg / t ore) - Cyanide used minus residual cyanide - determined.
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Abstract
Description
Die Erfindung betrifft ein Verfahren zur Laugung von Gold und Silber aus Erzen, Erzkonzentraten und Bergematerial aus früheren unvollständigen Laugungen durch Mahlen des zu laugenden Materials in Gegenwart einer cyanidischen Laugungslösung, welche einen pH-Wert von 8 bis 13 aufweist und eine Peroxoverbindung enthält.The invention relates to a method for leaching gold and silver from ores, ore concentrates and mining material from previous incomplete leachings by grinding the material to be leached in the presence of a cyanide leaching solution which has a pH of 8 to 13 and contains a peroxo compound.
Die Laugung von Cyanokomplexe bildenden Edelmetallen, insbesondere Gold und Silber, aus Erzen, Erzkonzentraten und anderen teilchenförmigen Materialien, wie beispielsweise Bergematerial aus früheren unvollständigen Laugungen, unter Verwendung einer cyanidhaltigen alkalischen Laugungslösung und eines Oxidationsmittels ist lange bekannt und wird seit über hundert Jahren bereits im betriebstechnischen Maßstab angewandt.The leaching of precious metals forming cyanocomplexes, in particular gold and silver, from ores, ore concentrates and other particulate materials, such as recovery material from previous incomplete leachings, using a cyanide-containing alkaline leaching solution and an oxidizing agent has been known for a long time and has been used in industrial engineering for over a hundred years Scale applied.
Bei der sogenannten Haufenlaugung wird das auf 10 bis 50 mm vorgebrochene Erz aufgehaldet und mit einer wäßrigen Cyanidlösung berieselt; als Oxidationsmittel dient üblicherweise Luftsauerstoff, jedoch können auch Peroxoverbindungen dem Erzhaufen oder der Laugungslösung zugesetzt werden - DE-PS 38 30 703, DE-Patentanmeldung P 40 17 899.4, GB-A 2219474.In so-called heap leaching, the ore that has been broken down to 10 to 50 mm is piled up and sprinkled with an aqueous cyanide solution; Usually atmospheric oxygen is used as the oxidizing agent, but peroxo compounds can also be added to the ore heap or the leaching solution - DE-PS 38 30 703, DE-patent application P 40 17 899.4, GB-A 2219474.
Bei der sogenannten Rührlaugung wird feingemahlenes Erz in Tanks oder anderen Behältern gelaugt. Die Goldausbringungsrate ist hier höher als bei der Haufenlaugung, allerdings ist auch der Verfahrensaufwand bedeutend höher. Die Rührlaugung erfordert eine durchschnittliche Aufmahlung des zu laugenden Erzes auf weniger als 100 µm; meist wird ein Mahlgrad gefordert, wonach mindestens 80 % des Mahlguts kleiner 45 µm ist.In the so-called stirring leaching, finely ground ore is leached in tanks or other containers. The gold yield rate is higher here than in the case of heap leaching, but the process costs are also significantly higher. The stirring leaching requires an average grinding of the ore to be leached to less than 100 µm; Usually a degree of grinding is required, according to which at least 80% of the ground material is smaller than 45 µm.
Zur Aufmahlung des Erzes werden bekannte diskontinuierlich und kontinuierlich arbeitende Naßmühlen, insbesondere Kugelmühlen und Stabmühlen, verwendet. Die Aufmahlung erfolgt in einer, meistens aber in zwei oder mehr Stufen, wobei das Überkorn jeweils rezykliert wird. Die erhaltene Trübe aus dem aufgemahlenen Erz und im allgemeinen Wasser wird mit Cyanid und ggf. weiteren Laugungschemikalien versetzt und dann den Laugungstanks zugeführt.Known discontinuously and continuously operating wet mills, in particular ball mills and rod mills, are used to grind the ore. The grinding takes place in one, but mostly in two or more stages, the oversize being recycled in each case. The resulting slurry from the ground ore and generally water is mixed with cyanide and possibly other leaching chemicals and then fed to the leaching tanks.
Bei der Rührlaugung beträgt die Laugungsdauer bei Begasung mit Luft meist 15 bis 30 Stunden, sie konnte aber durch Verwendung von Peroxoverbindungen, wie Wasserstoffperoxid, Calciumperoxid oder Peroxoboraten, anstelle oder in Ergänzung zur Luftbegasung wesentlich verkürzt werden - DE-PS 36 37 082, DE-PS 38 30 703, DE-Patentanmeldung P 40 17 899.4.In the case of stirring leaching, the leaching time for fumigation with air is usually 15 to 30 hours, but it could be significantly shortened by using peroxo compounds, such as hydrogen peroxide, calcium peroxide or peroxoborates, instead of or in addition to air fumigation - DE-PS 36 37 082, DE- PS 38 30 703, DE patent application P 40 17 899.4.
Seit einiger Zeit verwenden einige Minen die sogenannte "Cyanidation-in-mill"-Technik. Bei dieser Laugungsmethode wird das Cyanid vor oder während des Mahlens zugesetzt und die Verweilzeit des Erzes in der Mühle verwendet, um die Laugungszeit in den Tanks einer Rührlaugung zu verkürzen. Während bei völlig durchoxidierten Erzen passable Laugungsergebnisse bereits in der Mühle erzielt werden können, eignete sich diese Methode zunächst kaum zur Laugung sulfidischer Erze, weil hier in der Mühle reduktive Bedingungen vorherrschen und kein oder zu wenig Sauerstoff für die Laugung verfügbar ist. Um auch sulfidhaltige Erze der "Cyanidation-in-mill"-Technik besser zugänglich zu machen, wurden von verschiedenen Minen auch Oxidationsmittel eingesetzt: Während mit reinem Sauerstoff keine Verbesserung möglich war, konnte durch Verwendung von Wasserstoffperoxid die Goldausbeute in der Mühle gesteigert und der NaCN-Verbrauch reduziert werden -CA 102(14): 117216r (Smith, M.E. et. al. in Proc. SME Fall Meeting 1983, 41, 43-49, ed. Hiskey, J. Brent. Soc. Min. Eng. AIME : Littleton, Colo).Some mines have been using the so-called "cyanidation-in-mill" technique for some time. In this leaching method, the cyanide is added before or during grinding and the ore residence time in the mill is used to shorten the leaching time in the tanks of a stirred leach. While passable leaching results can already be achieved in the mill with fully oxidized ores, this method was initially unsuitable for leaching sulfidic ores, because here reductive conditions prevail in the mill and no or too little oxygen is available for leaching. In order to make sulfide-containing ores more accessible using the "cyanidation-in-mill" technique, various mines also used oxidizing agents: While no improvement was possible with pure oxygen, the use of hydrogen peroxide increased the gold yield in the mill and the NaCN - Consumption can be reduced -CA 102 (14): 117216r (Smith, ME et. Al. In Proc. SME Fall Meeting 1983, 41, 43-49, ed. Hiskey, J. Brent. Soc. Min. Eng. AIME: Littleton, Colo).
Aufgabe der Erfindung ist, die "Cyanidation-in-mill"-Technik dahingehend zu verbessern, daß eine gegenüber der Verwendung von Wasserstoffperoxid noch höhere Goldausbeute erzielt werden kann. Es sollte damit möglich werden, nicht nur die gesamte Laugungsdauer - Zeitaufwand für die Mahlung und die nachfolgende Rührlaugung - bei hoher Goldausbeute weiter zu verkürzen, sondern nach Möglichkeit sogar auf die Rührlaugung zu verzichten.The object of the invention is to improve the "cyanidation-in-mill" technique in such a way that an even higher gold yield can be achieved compared to the use of hydrogen peroxide. It should be possible not only to further shorten the total leaching time - time required for grinding and the subsequent stirring leaching - with a high gold yield, but also, if possible, to do without the stirring leaching.
Die Aufgabe wird gelöst durch ein Verfahren zur Laugung von Gold und Silber aus Erzen, Erzkonzentraten und Bergematerial durch Mahlen des zu laugenden Materials in Gegenwart einer cyanidischen Laugungslösung, welche einen pH-Wert von 8 bis 13 aufweist und eine Peroxoverbindung enthält, dadurch gekennzeichnet, daß als Peroxoverbindung mindestens eine Peroxoboratverbindung anwesend ist.The object is achieved by a process for the leaching of gold and silver from ores, ore concentrates and mining material by grinding the material to be leached in the presence of a cyanide leaching solution which has a pH of 8 to 13 and contains a peroxo compound, characterized in that at least one peroxoborate compound is present as the peroxo compound.
Für das erfindungsgemäße Verfahren ist wesentlich, daß eine wirksame Menge Peroxoborat in gelöster und/oder feinst verteilter Form anwesend ist. Die erforderliche Gesamtmenge an Peroxoborat kann bereits zu Beginn der Laugung in der Mühle anwesend sein, oder das Peroxoborat wird während der Laugung in einer oder mehreren Portionen, beispielsweise vor jeder Mahlstufe eines mehrstufigen Mahlverfahrens, zugesetzt oder aus einem zugesetzten Borat und Wasserstoffperoxid in-situ gebildet. Die Zugabe eines Peroxoborats wird gegenüber der in-situ-Bildung in der Laugungstrübe bevorzugt. Das Peroxoborat kann pulverförmig, als wäßrige Lösung oder Suspension dem zu laugenden Material, der cyanidischen Laugungslösungs oder der Laugungstrübe zugesetzt werden.It is essential for the process according to the invention that an effective amount of peroxoborate is present in dissolved and / or finely divided form. The total amount of peroxoborate required can be present in the mill at the start of the leaching, or the peroxoborate is added in one or more portions during the leaching, for example before each grinding stage of a multi-stage grinding process, or is formed in situ from an added borate and hydrogen peroxide . The addition of a peroxoborate is preferred over the in situ formation in the leach slurry. The peroxoborate can be added in powder form, as an aqueous solution or suspension to the material to be leached, the cyanide leaching solution or the leaching slurry.
Die wirksame Menge Peroxoborat, welche stark von dem zu laugenden Material abhängt, läßt sich anhand orientierender Versuche leicht ermitteln. Pro t des zu laugenden Materials werden im allgemeinen 1 bis 100 Äquivalente Peroxoborat, berechnet als BO₃-, ausreichend sein. Vorzugsweise liegt der Bedarf zwischen 10 und 60 Äquivalenten Peroxoborat. Als Aktivsauerstoffverbindung spalten Peroxoborate bzw. das durch Hydrolyse entstehende Wasserstoffperoxid Sauerstoff ab; der Sauerstoff, das Wasserstoffperoxid sowie das Peroxoborat können als Oxidationsmittel in den Laugungsprozeß eingreifen.The effective amount of peroxoborate, which strongly depends on the material to be leached, can easily be determined on the basis of preliminary experiments. Per t of the material to be leached, 1 to 100 equivalents of peroxoborate, calculated as BO₃-, will generally be sufficient. The requirement is preferably between 10 and 60 equivalents of peroxoborate. As the active oxygen compound, peroxoborates or the hydrogen peroxide formed by hydrolysis split off oxygen; oxygen, hydrogen peroxide and peroxoborate can act as oxidizing agents in the leaching process.
Als Peroxoborate, hierunter werden auch deren Hydrate verstanden, kommen solche der Alkali- und Erdalkalimetalle infrage, prinzipiell aber auch Peroxoborate von anderen Metallen, wie z. B. Zink. Besonders vorteilhaft lassen sich die im Handel erhältlichen Peroxoborate, nämlich das sogenannte Natriumperboratmono- und -tetrahydrat sowie Calciumperborat, verwenden. Einsetzbar sind auch sogenannte superoxidierte Peroxoborate, wie sie aus der DE-OS 28 11 554 und DE-OS 35 05 158 bekannt wurden.Peroxoborates, including their hydrates, are those of the alkali and alkaline earth metals, but in principle also peroxoborates of other metals, such as, for. B. Zinc. The commercially available peroxoborates, namely the so-called sodium perborate mono- and tetrahydrate and calcium perborate, can be used particularly advantageously. So-called superoxidized peroxoborates, such as are known from DE-OS 28 11 554 and DE-OS 35 05 158, can also be used.
Wie bei der Haufen- und Rührlaugung wird auch die Laugung in der Mühle bei einem pH-Wert von 8 bis 13, vorzugsweise 9 bis 12, durchgeführt. Die pH-Einstellung erfolgt in an sich bekannter Weise mittels Alkalien, wie insbesondere Kalkmilch und Natronlauge. Während des Mahlprozesses kann es zweckmäßig sein, eine pH-Anpassung auf als optimal erkannte Werte vorzunehmen.As with heap and stirring leaching, the leaching in the mill is carried out at a pH of 8 to 13, preferably 9 to 12. The pH is adjusted in a manner known per se using alkalis, such as, in particular, lime milk and sodium hydroxide solution. During the grinding process, it may be advisable to adjust the pH to values recognized as optimal.
Der Cyanidgehalt, berechnet als CN, in der Laugungslösung wird üblicherweise zwischen 0,005 und 2,5 Gew.-% liegen. Bevorzugt werden Cyanidgehalte zwischen 0,02 und 0,2 Gew.-%. Cyanid wird als Alkalicyanid, insbesondere Natriumcyanid, oder als Calciumcyanid, etwa in Form der sogenannten "black cyanide" eingesetzt. Das Cyanid kann in fester oder gelöster Form einer wäßrigen Trübe, welche das zu laugende Material enthält, zugesetzt werden, oder eine cyanidhaltige Laugungslösung wird direkt zur Herstellung der Laugungstrübe eingesetzt.The cyanide content, calculated as CN, in the leaching solution will usually be between 0.005 and 2.5% by weight. Cyanide contents between 0.02 and 0.2% by weight are preferred. Cyanide is used as an alkali cyanide, in particular sodium cyanide, or as calcium cyanide, for example in the form of the so-called "black cyanide". The cyanide can be added in solid or dissolved form to an aqueous slurry containing the material to be leached, or a cyanide-containing leaching solution is used directly to prepare the leaching slurry.
Zur erfindungsgemäßen Laugung kommen bekannte Naßmahlaggregate infrage; Kugelmühlen und Stabmühlen werden bevorzugt. Die Mahldauer richtet sich nach dem zu laugenden Material und gewünschten Extraktionsgrad. Üblicherweise wird zwischen 15 Minuten und 2 Stunden gemahlen. Die Feststoffkonzentration der Laugungstrübe während der Mahlung kann sich in weiten Bereichen bewegen, üblicherweise zwischen 25 und 60 Gew.-%. Der Mahlgrad bewegt sich im Bereich, wie er für die Rührlaugung üblich ist.Known wet grinding units are suitable for leaching according to the invention; Ball mills and bar mills are preferred. The grinding time depends on the material to be leached and the desired degree of extraction. It is usually milled between 15 minutes and 2 hours. The solids concentration of the leach sludge during grinding can vary over a wide range, usually between 25 and 60% by weight. The degree of grinding is in the range that is customary for stirring leaching.
Nach beendeter Mahlung kann die Laugungstrübe, soweit erforderlich, einer Rührlaugung oder Drucklaugung zugeführt werden, um den Extraktionsgrad weiter zu erhöhen. Ansonsten werden die in der Laugungstrübe in gelöster Form vorliegenden Edelmetallcyanokomplexe mittels bekannter Prozeßstufen - beispielhaft genannt seien der Carbon-in-Pulp (CIP)- und Resin-in-Pulp (RIP)-Prozeß sowie der Merrill-Crowe-Prozeß - zur weiteren Edelmetallgewinnung abgetrennt.After the grinding has ended, the leaching sludge can, if necessary, be subjected to a stirring leaching or pressure leaching in order to further increase the degree of extraction. Otherwise, the precious metal cyanocomplexes present in solution in the leaching slurry are used for further precious metal extraction by known process stages - the carbon-in-pulp (CIP) and resin-in-pulp (RIP) process and the Merrill-Crowe process separated.
Während bei Verwendung von Wasserstoffperoxid als Oxidationsmittel bei der Laugung in der Mühle eine ähnliche Extraktionskinetik wie bei der Rührlaugung gemäß DE-PS 36 37 082 beobachtet wurde, verläuft die Extraktion bei Verwendung der äquivalenten Menge eines Peroxoborats überraschenderweise beschleunigt. Bei gegebener Laugungsdauer wird dadurch die Goldausbeute gesteigert. Teilweise erübrigt sich damit eine sich an die Laugung in der Mühle anschließende Rührlaugung. Aus der Verwendung von Peroxoborat resultiert zudem eine Verminderung des Cyanidverbrauchs. Durch die genannten Faktoren wird die Wirtschaftlichkeit der Laugung von Gold und Silber aus Erzen, Erzkonzentraten und Bergematerial aus früheren unvollständigen Laugungen, etwa Haufenlaugungen, gesteigert.While using hydrogen peroxide as an oxidizing agent during leaching in the mill a similar extraction kinetics was observed as with stirring leaching according to DE-PS 36 37 082, the extraction is surprisingly accelerated when using the equivalent amount of a peroxoborate. For a given leaching period, the gold yield is increased. In some cases there is no need for a stirring leaching after the leaching in the mill. The use of peroxoborate also results in a reduction in cyanide consumption. The factors mentioned increase the efficiency of the leaching of gold and silver from ores, ore concentrates and mining material from previous incomplete leachings, such as heap leaching.
Die Vorteile des Peroxoborats sind umso überraschender, als sich andere Peroxoverbindungen, darunter Calciumperoxid, Natriumpercarbonat und Ammoniumperoxodisulfat, bezüglich der Goldausbeute als gegenüber Wasserstoffperoxid weniger wirksam erwiesen.The benefits of peroxoborate are all the more surprising given that other peroxo compounds, including calcium peroxide, sodium percarbonate and ammonium peroxodisulfate, have been found to be less effective in terms of gold yield than hydrogen peroxide.
Aus den nachfolgenden Beispielen folgt die überragende Wirkung von Peroxoboraten bei der Laugung in der Mühle gegenüber anderen Peroxoverbindungen.The outstanding effect of peroxoborates in leaching in the mill compared to other peroxo compounds follows from the examples below.
Eingesetzt wurde bei allen Versuchen ein sulfidhaltiges Erz, der sogenannte "mill feed" der Vumbachikwe Mine, Zimbabwe. Mit diesem Erz kann das cyanidisch laugbare Gold, 80 - 85 % des Goldgehalts, bei Anwendung von Wasserstoffperoxid gemäß DE-PS 36 37 082 in 4 bis 6 Stunden extrahiert werden.A sulphide-containing ore, the so-called "mill feed" from the Vumbachikwe Mine, Zimbabwe, was used in all experiments. With this ore, the cyanide-leachable gold, 80-85% of the gold content, can be extracted in 4 to 6 hours when using hydrogen peroxide according to DE-PS 36 37 082.
Die Laugungsversuche mit der "Cyanidation-in-mill"-Technik wurden in einer Stabmühle aus Edelstahl mit einem Gesamtvolumen von 4.5 1 durchgeführt. Als Mahlkörper wurden 12 Edelstahlstäbe (18.2 cm lang, 2,5 cm Durchmesser) verwendet, die damit 24 % des Mühlenvolumens ausfüllten. Die Mahlungen wurden jeweils mit 400 g Erz und 600 g Wasser (40 % Feststoff) durchgeführt. Das Volumen der entstehenden Erzaufschlämmung füllt weitere 16 % der Mühle aus, so daß man auf eine Gesamtbefüllung der Mühle von 40 % kommt.The leaching tests using the "cyanidation-in-mill" technique were carried out in a rod mill made of stainless steel with a total volume of 4.5 l. 12 stainless steel rods (18.2 cm long, 2.5 cm diameter) were used as grinding media, thus filling 24% of the mill volume. The grindings were each carried out with 400 g of ore and 600 g of water (40% solids). The volume of the resulting ore slurry fills a further 16% of the mill, so that the total filling of the mill is 40%.
Weitere Laugungsparameter sind:
Die verschiedenen Oxidationsmittel sowie der Kalk wurden zu Beginn der Mahlung in die Mühle eingetragen. Nach Beendigung der Mahlung wurden die Goldausbeute - gelaugtes Gold, bezogen auf den Gesamt-Au-Gehalt des Erzes -, der O₂-Gehalt (ppm) in der Laugungslösung - bestimmt mittels einer O₂-Elektrode - und der Cyanidverbrauch (kg/t Erz) - eingesetztes Cyanid abzüglich Restcyanid - bestimmt.The various oxidizing agents and the lime were added to the mill at the beginning of the grinding. After the grinding, the gold yield - leached gold, based on the total Au content of the ore -, the O₂ content (ppm) in the leaching solution - determined using an O₂ electrode - and the cyanide consumption (kg / t ore) - Cyanide used minus residual cyanide - determined.
Die Ergebnisse der erfindungsgemäßen Beispiele E 1 bis E 5 sowie jene der Vergleichsbeispiele V 1 bis V 7 sind der nachfolgenden Tabelle zu entnehmen. Es zeigt sich hieraus die überlegene Wirkung von zugesetzten Perboraten (E 1 bis E 4); in-situ gebildetes Natriumperborat (E 5) führt zwar zur etwa gleichen Goldausbeute wie H₂O₂, jedoch konnte der NaCN-Verbrauch abgesenkt werden.
Claims (5)
dadurch gekennzeichnet,
daß als Peroxoverbindung mindestens eine Peroxoboratverbindung anwesend ist.Process for leaching gold and silver from ores, ore concentrates and mining material from previous incomplete leachings by grinding the material to be leached in the presence of a cyanide leaching solution which has a pH of 8 to 13 and contains a peroxo compound,
characterized,
that at least one peroxoborate compound is present as the peroxo compound.
dadurch gekennzeichnet,
daß die Laugungslösung ein Alkali- und/oder Erdalkaliperoxoborat in gelöster und/oder ungelöster Form enthält.Method according to claim 1,
characterized,
that the leaching solution contains an alkali and / or alkaline earth peroxoborate in dissolved and / or undissolved form.
dadurch gekennzeichnet,
daß man zu Beginn und/oder während der Mahlung der Trübe aus dem zu laugenden Material und der Laugungslösung ein pulverförmiges Peroxoborat in einer wirksamen Menge zugibt.Method according to claim 1 or 2,
characterized,
that a powdery peroxoborate is added in an effective amount at the beginning and / or during the grinding of the slurry from the material to be leached and the leaching solution.
dadurch gekennzeichnet,
daß man pro t des zu laugenden Materials 1 bis 100, vorzugsweise 10 bis 60, Äquivalente Peroxoborat, berechnet als BO₃-, einsetzt.Method according to one of claims 1 to 3,
characterized,
that 1 to 100, preferably 10 to 60, equivalents of peroxoborate, calculated as BO₃-, are used per t of the material to be leached.
dadurch gekennzeichnet,
daß die Laugungslösung einen pH-Wert von 9 bis 12 aufweist und 0,02 bis 0,2 Gew.-% Cyanid, berechnet als CN, enthält.Method according to one or more of claims 1 to 4,
characterized,
that the leaching solution has a pH of 9 to 12 and contains 0.02 to 0.2% by weight of cyanide, calculated as CN.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE4114514 | 1991-05-03 | ||
DE4114514A DE4114514A1 (en) | 1991-05-03 | 1991-05-03 | METHOD FOR THE LOWING OF GOLD AND SILVER |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0512247A2 true EP0512247A2 (en) | 1992-11-11 |
EP0512247A3 EP0512247A3 (en) | 1993-05-05 |
EP0512247B1 EP0512247B1 (en) | 1996-02-28 |
Family
ID=6430935
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP92105566A Expired - Lifetime EP0512247B1 (en) | 1991-05-03 | 1992-04-01 | Method for leaching gold and silver |
Country Status (9)
Country | Link |
---|---|
EP (1) | EP0512247B1 (en) |
AT (1) | ATE134712T1 (en) |
AU (1) | AU642087B2 (en) |
BR (1) | BR9201586A (en) |
CA (1) | CA2067841A1 (en) |
DE (2) | DE4114514A1 (en) |
ES (1) | ES2084203T3 (en) |
ZA (1) | ZA923190B (en) |
ZW (1) | ZW4892A1 (en) |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE19829274C2 (en) * | 1998-07-01 | 2002-06-20 | Otb Oberflaechentechnik Berlin | Process for the recovery of precious metals |
DE102020209885A1 (en) | 2020-08-05 | 2022-02-10 | Robert Bosch Gesellschaft mit beschränkter Haftung | Ball mill and process for extracting gold and/or silver and/or at least one platinum group metal |
DE102020209884A1 (en) | 2020-08-05 | 2022-02-10 | Robert Bosch Gesellschaft mit beschränkter Haftung | Method of extracting gold |
DE102020209880A1 (en) | 2020-08-05 | 2022-02-10 | Robert Bosch Gesellschaft mit beschränkter Haftung | Process for the extraction of at least one precious metal |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AU587850B2 (en) * | 1985-08-26 | 1989-08-31 | Bendigo Gold Associates Pty. Ltd. | A method of pre-treating an ore with hot alkali to improve the recovery of metal valves |
DE4017899C1 (en) * | 1990-06-02 | 1991-11-14 | Degussa Ag, 6000 Frankfurt, De | Extn. of silver and gold from ores - by contacting ore with aq. leaching soln. contg. cyanide in presence of peroxo:borate, and sepg. cyano complexes formed |
-
1991
- 1991-05-03 DE DE4114514A patent/DE4114514A1/en not_active Withdrawn
-
1992
- 1992-03-27 ZW ZW48/92A patent/ZW4892A1/en unknown
- 1992-04-01 AT AT92105566T patent/ATE134712T1/en not_active IP Right Cessation
- 1992-04-01 EP EP92105566A patent/EP0512247B1/en not_active Expired - Lifetime
- 1992-04-01 ES ES92105566T patent/ES2084203T3/en not_active Expired - Lifetime
- 1992-04-01 DE DE59205427T patent/DE59205427D1/en not_active Expired - Fee Related
- 1992-04-29 BR BR929201586A patent/BR9201586A/en not_active Application Discontinuation
- 1992-04-30 ZA ZA923190A patent/ZA923190B/en unknown
- 1992-05-01 CA CA002067841A patent/CA2067841A1/en not_active Abandoned
- 1992-05-01 AU AU15960/92A patent/AU642087B2/en not_active Ceased
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AU587850B2 (en) * | 1985-08-26 | 1989-08-31 | Bendigo Gold Associates Pty. Ltd. | A method of pre-treating an ore with hot alkali to improve the recovery of metal valves |
DE4017899C1 (en) * | 1990-06-02 | 1991-11-14 | Degussa Ag, 6000 Frankfurt, De | Extn. of silver and gold from ores - by contacting ore with aq. leaching soln. contg. cyanide in presence of peroxo:borate, and sepg. cyano complexes formed |
Also Published As
Publication number | Publication date |
---|---|
ES2084203T3 (en) | 1996-05-01 |
ZA923190B (en) | 1993-01-27 |
CA2067841A1 (en) | 1992-11-04 |
EP0512247B1 (en) | 1996-02-28 |
ZW4892A1 (en) | 1993-02-17 |
DE59205427D1 (en) | 1996-04-04 |
AU1596092A (en) | 1992-11-05 |
DE4114514A1 (en) | 1992-11-05 |
ATE134712T1 (en) | 1996-03-15 |
BR9201586A (en) | 1992-12-15 |
AU642087B2 (en) | 1993-10-07 |
EP0512247A3 (en) | 1993-05-05 |
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