EP1747066B1 - Collector for sulfidic ores - Google Patents

Abstract

The present invention relates a flotation reagent for sulfidic ores, containing at least one compound of formula (1), wherein R2, R3, R4, R5, R6 and R7, independent of one another, represent hydrogen or groups containing 1 to 15 carbon atoms or groups containing oxygen or nitrogen, and at least another compound serving as collector and containing at least one sulfur atom that is directly bound to a carbon or phosphorus atom, wherein the carbon or phosphorus atom is directly bound to at least another sulfur atom or an oxygen atom.

Description

The present invention relates to the use of collectors in the flotation of sulfidic ores.

In the flotative recovery of sulfidic ores, in particular copper or molybdenum ores, commercially diverse types of collectors, such as dithiophosphates, xanthates, xanthogen formates and thionocarbamates ( Schubert: Processing of solid mineral raw materials, Volume II, 1977, p. 296 ff) and mixtures thereof used in combination with foaming agents. For example, the process of flotation separates copper and molybdenum sulfides from gangue minerals.

Collectors cause a wetting of the surface of the valuable mineral, which leads to a hydrophobization of the mineral particles. By injecting air into the aqueous flotation pulp, air bubbles are produced, to which the hydrophobized mineral particles adhere and are discharged with these to the surface of the flotation pulp. The floating value mineral, called concentrate, is skimmed off, while gangue minerals remain in the pulp.

Foamer is added to modify the foaming. Examples of commercially available foaming agents include alcohols, polypropylene glycols and their ethers, and MIBC (methylisobutylcarbinol).

U.S. 4,699,711 discloses a process for flotation of sulfide minerals with preferably short chain alkyl substituted thionocarbamates.

WO-02/38277 discloses the use of mixtures of thionocarbamates and mercaptobenzothiazoles as collectors for the flotation of sulfidic ores, particularly copper ore associated with molybdenum and gold.

U.S. 2,875,896 discloses a foam flotation process using 8-quinolinol and heating oil as a collector.

U.S. 4,178,235 discloses the use of 5-hydroxyquinolinol as the sole collector in foam floatation.

GB-A-798 769 and US-A-4,178,235 describe the flotation of niobium minerals with 8-quinolinol and 5-hydroxyquinoline, respectively. GB-A-826,827 describes in addition to 8-quinolinol still alkyl-substituted 8-quinolinol derivatives for the flotation of niobium minerals.

8-quinolinol has a high affinity for metal ions and forms with these complexes, so-called oxinates. Therefore, 8-quinolinol is also used as a precipitating reagent for various metal ions.

GB-A-887 469 describes a method of recovering 8-quinolinol after use.

When pyrite-containing ores are flotated at pH values below 10 with commercially available sulfidic collectors such as dialkyl dithiophosphates, xanthates, dialkyl xanthenormiates or dialkyl thionocarbamates, concentrates with relatively high pyrite concentrations are obtained. The dialkylthionocarbamates are already considered to be very selective towards pyrite compared to xanthates and dithiophosphates.

This high pyrite content has a negative effect on the subsequent processing of the concentrate. For one, the effectiveness of the reduction process is reduced and high levels of sulfur oxides are formed, which pollute the environment or cause their disposal to incur high costs.

In order to reduce the proportion of pyrite in the concentrate and to increase the value of mineral content, lime is added to the flotation pulp, which causes an increase in the pH of the flotation pulp to more than 10, depending on the amount. The added Lime quantities vary depending on the pyrite content between zero and several kg per ton of ore. The lime thus contributes significantly to the reagent costs of the flotation process. Reducing the amount of lime and lowering the pH to less than 10 would thus not only contribute to the reduction of sulfur oxide emissions into the environment, but also bring about a saving in reagent costs.

The object of the present invention was to find an improved collector type for sulfidic ores, which gives better flotation results than prior art collectors. The object of the invention is furthermore to reduce the required amounts of pH modifiers, in particular lime, which is used for increasing the pH and for pressing pyrite.

Surprisingly, it has been found that the use of 8-hydroxyquinolinol derivatives in combination with conventional collectors in the flotation of sulfidic ores causes a significant improvement in the flotation results. In particular, by combining 8-quinolinol with conventional collectors, a significant improvement in the flotation of pyrite-containing copper ores could be achieved. Especially in combination with thionocarbamates, a significant improvement in the flotation of copper ore was found with 8-quinolinol.

worin R², R³, R⁴, R⁵, R⁶ und R⁷ unabhängig voneinander Wasserstoff oder Gruppen enthaltend 1 bis 15 Kohlenstoffatome oder Gruppen enthaltend Sauerstoff oder Stickstoff sind, und mindestens eine weitere, als Sammler für sulfidische Erze dienende Verbindung, welche wenigstens ein Schwefelatom enthält, das direkt an ein Kohlenstoff- oder Phosphoratom gebunden ist, und wobei dieses Kohlenstoff- oder Phosphoratom an wenigstens ein weiteres Schwefelatom oder an ein Stickstoffatom oder an ein Sauerstoffatom direkt gebunden ist, wobei das Mischungsverhältnis der Verbindungen der Formel 1 zu den weiteren Sammlern 0,1:99,9 bis 20:80 beträgt.The invention thus relates to a flotation reagent for sulfidic ores, comprising at least one compound of the formula (1)

wherein R ² , R ³ , R ⁴ , R ⁵ , R ⁶ and R ^{7 are} independently hydrogen or groups containing 1 to 15 carbon atoms or groups containing oxygen or nitrogen, and at least one other, serving as a collector for sulfidic ores compound which contains at least one sulfur atom which is bonded directly to a carbon or phosphorus atom, and wherein said carbon or phosphorus atom is directly bonded to at least one further sulfur atom or to a nitrogen atom or to an oxygen atom, wherein the mixing ratio of the compounds of formula 1 to the other collectors is 0.1: 99.9 to 20:80.

Another object of the invention is the use of the flotation reagent according to the invention for the flotation of sulfidic ores.

Another object of the invention is a method for flotation of sulfidic ores by bringing the flotation reagent according to the invention with the sulfidic ores in contact.

Another object of the invention is the use of compounds of formula 1 as additive to collectors for sulfidic ores.

With the flotation reagent according to the invention, improved results in selectivity and yield can be achieved in the flotation of metal sulfides in comparison to standard collectors. The already towards pyrite selective properties of the other collectors can be significantly improved by using compounds of formula (I). In particular, ores which have a high pyrite content and are usually floated at a pH above 10, can be floated already at pH values of 7 to 10, for example at pH 8.5 to 9.0. In this case, the co-filtered pyrite content in the resulting concentrate is significantly lower than with currently available collectors at the same pH value or the value of mineral content is higher.

The sulfidic ores are preferably copper-containing ores which have up to 90% by weight of pyritic fractions.

All metal sulfides and metals (except Fe) can be flotated, with Cu, Mo, Pb, Zn, Co, Au, Ag, Pt and Ni being particularly preferred. Particularly good results can be observed in the treatment of Cu and Mo. The flotation reagent according to the invention can be used in a wide pH range, for example 2 to 12, preferably 5 to 12, and is added to the aqueous pulp in a concentration of preferably 0.001 to 1.0 kg / ton of crude ore.

In a preferred embodiment, the compounds of the formula (1) are those in which R ² , R ³ , R ⁴ , R ⁵ , R ⁶ and R ⁷ independently of one another are H or C ₁ - to C ₄ -alkyl, especially all H mean.

in denen die freigelassenen Valenzen durch organische Reste oder Schwefelatome abgesättigt sind.The other collectors in preferred embodiments are those compounds which are structural units of the formulas

in which the released valences are saturated by organic radicals or sulfur atoms.

oder um Xanthate der Formel (7)

oder um Xanthogenformiate der Formel (8)

oder um Thionocarbamate der Formel 9

oder um Mercaptobenzthiazole der Formel 10

worin
R⁸ und R⁹ unabhängig voneinander für Kohlenwasserstoffreste mit 1 bis 10 Kohlenstoffatomen, insbesondere C₁- bis C₁₀-Alkyl, C₁- bis C₁₀-Alkenyl, C₁- bis C₅-Alkyl, C₁- bis C₅-Alkenyl, Phenyl, Benzyl oder Naphthyl, und
M⁺ für ein Kation, insbesondere ein Metallion oder ein Ammoniumion stehen.In particularly preferred embodiments, the further collectors are dithiophosphates of the formula (6)

or Xanthate of the formula (7)

or to xanthogen formates of the formula (8)

or thionocarbamates of formula 9

or mercaptobenzothiazoles of the formula 10

wherein
R ⁸ and R ⁹ independently of one another are hydrocarbon radicals having 1 to 10 carbon atoms, in particular C ₁ - to C ₁₀ -alkyl, C ₁ - to C ₁₀ -alkenyl, C ₁ - to C ₅ -alkyl, C ₁ - to C ₅ - Alkenyl, phenyl, benzyl or naphthyl, and
M ⁺ stand for a cation, in particular a metal ion or an ammonium ion.

The mixing ratio of the compounds of the formula 1 to the other collectors represented by the formulas 2 to 10 is preferably 0.1: 99.9 to 20:80, in particular 1:99 to 10:90. In a preferred embodiment, the flotation reagent according to the invention contains between 0.1 and 20% by weight of 8-quinolinol.

With the flotation reagent according to the invention, a significant improvement in spreading and selectivity is achieved compared to the collectors of the prior art. Examples 1 to 6 clearly show that the application of copper and molybdenum is higher than with the corresponding standard reagent.

By using the reagent of the present invention with a thionocarbamate, copper concentrates having 5-9% higher copper concentrations were obtained at pH values between 8.5 and 10.5 than with a conventional thionocarbamate. The copper yield was also significantly improved between 0.9 and 2.4 percentage points.

Examples:

The following table represents the flotative results of the inventive collector in comparison to the standard reagent. Laboratory flotation experiments on a Chilean copper ore have been carried out. As a standard reagent (Comparative Examples 4 to 6), an ethylthio, O-Isopropylthionocarbamat and a dosage of 14 g / t Roherz task was used. A commercial foamer (MIBC) was added at a dosage of 15 g / t ore. The invention is illustrated in the Examples (Examples 1 to 3). It corresponds to the 94.4% ethylthio, O-isopropylthionocarbamate with an addition of 5.6% 8-quinolinol. The values obtained for the Copper content and spreading are mean values from three individual flotations. Table 1: Effectiveness of the inventive collector in comparison to the prior art example PH value Content Cu,% Spreading out Cu,% 1 8.5 10.8 93.4 2 9.5 11.1 92.8 3 10.5 11.2 92.2 4 (V) 8.5 9.9 91.0 5 (V) 9.5 10.3 91.6 6 (V) 10.5 10.7 91.3

The results show a consistently increased percentage application and a higher content of Cu by the flotation reagent according to the invention.

Claims (10)

1. A flotation reagent for sulfidic ores, which flotation reagent comprises a compound of the formula (1)

   

   where R², R³, R⁴, R⁵, R⁶ and R⁷, independently of one another are hydrogen or groups comprising 1 to 15 carbon atoms, or groups comprising oxygen or nitrogen, and at least one further compound acting as collector for sulfidic ores which comprises at least one sulfur atom which is directly bound to a carbon or phosphorus atom, and this carbon or phosphorus atom being directly bound to at least one further sulfur atom or a nitrogen atom or an oxygen atom, the mixing ratio of the compounds of the formula 1 to the further collectors being 0.1:99.9 to 20:80.
2. The flotation reagent as claimed in claim 1, wherein the further collector is selected from compounds which comprise structural units of the formulae

   

   

   

   

   where the free valencies are saturated by organic radicals or sulfur atoms.
3. The flotation reagent as claimed in claim 2, wherein the further collector is selected from dithiophosphates of the formula 6

   

   or xanthates of the formula (7)

   

   or xanthogen formates of the formula 8

   

   or thionocarbamates of the formula 9

   

   or mercaptobenzothiazoles of the formula 10

   

   where

   R⁸ and R⁹ independently of one another are hydrocarbon radicals having 1 to 10 carbon atoms, in particular C₁- to C₁₀-alkyl, C₁- to C₁₀-alkenyl, C₁- to C₅-alkyl, C₁- to C₅-alkenyl, phenyl, benzyl or naphthyl, and

   M⁺ is a cation, in particular a metal ion or an ammonium ion.
4. The flotation reagent as claimed in claim 1, comprising 8-quinolinol.
5. The use of the flotation reagent as claimed in one or more of claims 1 to 4 in amounts of 0.001 to 1.0 kg per tonne of crude ore for the flotation of sulfidic ores and metals.
6. The use as claimed in claim 5, the sulfidic ore being copper sulfide, nickel sulfide, zinc sulfide, lead sulfide or molybdenum sulfide.
7. The use of the flotation reagent as claimed in claim 5 and/or 6 in the flotation of sulfidic ores, the sulfidic ore comprising between 0 and 90% pyrite.
8. The use of the flotation reagent as claimed in one or more of claims 5 to 7 for the flotation of copper ores.
9. The use of the flotation reagent as claimed in one or more of claims 5 to 8 in a pH range of 7 to 10.
10. The use of compounds of the formula 1

    

    where R², R³, R⁴, R⁵, R⁶ and R⁷ independently of one another are hydrogen or groups comprising 1 to 15 carbon atoms or groups comprising oxygen or nitrogen, as additive for collectors for sulfidic ores.