DE2102303B2 - METHOD FOR FLOTATION OF MOLYBDA SULFIDE - Google Patents

Description

The invention relates to the separation and recovery of molybdenum sulfide from molybdenum sulfide and copper ore concentrates containing copper sulfide by froth flotation in the presence of a collector for Molybdenum sulphide and a trigger for copper sulphide to obtain a molybdenum concentrate in the Foam concentrate and a copper concentrate in the residue.

Sulphidic copper ores often contain small but economically significant amounts of molybdenite (MoS ₂ ), which is an important source of molybdenum when separated from the copper ore. For example, a typical low copper ore may contain about 1% copper sulfide and about 0.1-0.5% molybdenum disulfide. Such copper ores are treated by conventional foaming to obtain an ore concentrate with typically about 30% copper sulfides for a chalcopyrite ore, and with about 1% molybdenum disulfide, the molybdenite following the copper minerals in the flotation cycle. The molybdenite content of the copper ore concentrate is then advantageously separated off by selective flotation to obtain a molybdenum concentrate with 90 or more percent MoS ₃ . Sulphidic copper minerals and molybdenite are usually quoted by the same collectors. In the case of a selective flotation of molybdenite-containing copper concentrates, it is therefore necessary either to press the copper sulfides during the flotation of the molybdenite content of the concentrate or the molybdenite during the flotation of the copper sulfide content of the concentrate.

An industrially widespread process for carrying out the aforementioned selective flotation of molybdiinil consists in an aqueous turbidity of the molybdenite-containing Copper concentrate with a conventional collector for molybdenum sulfide and a Condition pusher for copper sulfide and then to carry out a foam ionization in order to obtain a molyb- f> s dänkonzcntrat in the foam and a copper concentrate to be obtained in the residue. The pushers used are complex sulfidic compounds of phosphorus, Arsenic or antimony and alkali. They are commercially available from many suppliers. One such The reagent is anamol "D", a mixture of arsenic trioxide and sodium sulfide. These so-called "Nokes-type" copper pushers do not destroy the ability of conventional copper collectors to mask them or only selectively block the collecting power of these collectors for copper minerals. It was found, that the content of pressing agent in the pulp is kept above certain empirically determined levels must be if it is to be effective. When the existing copper pressure amount for an effective effect insufficient either because an insufficient amount was used initially or because a The collector used becomes part of the initially available pressure means is used up or lost to float both sulphide minerals first allow the copper minerals to float back and no effective separation of the two will be achieved. The operating personnel of flotation plants has found that the amount of Nokes-type copper pressing agent required for ensuring an effective selective fiotation is required, in the range of 6.8 kg to 9 kg per ton to be treated Copper ore concentrates. Since Nokes-type reagents are relatively expensive, these mean relatively large quantities this reagent, which are necessary for an efficient separation, a significant cost increase for the last molybdenum produced.

After extensive research into the reasons for the high consumption of Nokes reagent, now found that if certain essential operating procedures and criteria are observed, a relative small amount of Nokes-type copper pressing agent is required to en.j effective separation of molybdenite of sulfidic copper minerals. It was found in particular that in one conventional foaming of a copper ore concentrate in the presence of a Nokcs-type reagent, the selective flotation of the mineral components effectively progresses until a point is reached at which the Reagent appears to lose almost all of its ability to depress copper minerals quite abruptly. At the same time, the electromotive force (EMF) of the flotation pulp, measured with the help of a normal Half-cell, constantly decreasing, whereby the abrupt loss of the pushability of the Nokes reagent becomes clear shows when the EMF of the turbidity comes close to minus 200 millivolts (-200 mV). Both appearances are apparently due to the progressive destruction or inactivation of the < Nokes reagent, which in turn appears to use air or other oxidizing gases as an aeration medium in conventional flotation. Based on this knowledge and Discoveries became the improved method for selective flotation described below found from molybdenite-containing copper concentrates

The improved method of the invention proceeds from conditioning an aqueous slurry Copper ore concentrates containing molybdenum sulfide and copper sulfide with a collector for molybdenum sulfide and a Nokcs-type Orückmille! for copper sulfide The conditioned pulp is then subjected to a foam notation in which is known per se Way an inert gas or gases as foaming c Means is or are used while the EMF of the turbidity is kept above a certain value

is used to increase the effectiveness of the push lever door copper sulfide to maintain. The amount of the mentioned copper pressurizing agent in the flotation pulp should be sufficient to keep the EMF of the turbidity above approx. -200 mV, measured with a platinum electrode in with respect to an ordinary GP glass electrode (calomel electrode). The foaming gas should not react with the copper pressure medium and this do not oxidize and is advantageously nitrogen or can be an inert gas such as helium and argon or a mixture of these gases. It is preferred to use nitrogen as the vent gas, though specially treated combustion gases and exhaust gases containing only nitrogen and other inert gases as well can be used advantageously.

Details of the invention emerge from the following description in conjunction with the claims and the drawing.

In the drawing shows

Fig. 1 is a diagram in which the pressed copper content the turbidity (i.e. the copper present in the residue) in relation to the time when the The turbidity is aerated with an oxidizing gas (air) and with a non-oxidizing gas (nitrogen), and

Fig. 2 is a diagram showing the relationship between indicates the percentage of copper pressed and the EMF of the flotation pulp.

The Nokes-type reagents used here as pushers were first disclosed in US Pat. No. 2,492,936 dated Described December 27, 1949 and can generally be considered the reaction product of at least two inorganic Compounds are defined, the reaction product being divalent sulfur, an alkali or alkaline earth cation (e.g. sodium, potassium, calcium, ammonium or the like) and connected so that it contains an element of phosphorus, arsenic or antimony. These reagents are in the facility well known.

Conventional froth flotation is normally carried out in stirrer flotation cells which Use air as a foaming gas. For the effective pressing of copper minerals in such The amount of Nokes-type reagent required by conventional froth flotation has heretofore been empirical determined by the operating personnel and was in the range of 6.8 to 9 kg per ton of copper concentrates to be treated. The research showed that when using a non-oxidizing Gas as a foam-forming gas instead of air and with retention of the electromotive force of the flotation pulp above a predetermined value, which is required for the pressing of the copper minerals Nokes-type reagent amount effectively to about one fifth to one half of the amount previously required is lowered.

When an inert gas non-reactive with respect to the strongly alkaline Nokes reagent is used as the foaming gas, the emf of the flotation pulp remains essentially constant and the Nokes-type reagent maintains its ability to depress copper minerals throughout the flotation . Moreover hei can use an inert gas as a medium schaumbiklendes a substantially lower amount of Nokes reagent type are used as copper urging means than is the case when air or another oxidizing gas as Schaumbildno ¹ is used. The nut in the practice of the invention.

Lichen non-oxidizing gases include, but are not necessarily limited to, nitrogen Gas, and are other inert gases such as helium and argon and various mixtures of these gases. A convenient source of this type of gas is exhaust or combustion gas, which is cooled and used for removal has been cleaned of dust particles and in a treatment of free oxygen, carbon dioxide and / or carbon monoxide has been released.

ίο The EMF of the flotation pulp is used by experts determined by well known techniques. In short, it becomes the electrical potential of the pulp measured with respect to the potential of a conventional standard half-cell. The absolute value of the EMF or the potential of the turbidity in millivolts depends on a number of factors including type and Composition of copper ore concentrate, type and concentration of Nokes reagent used and the type of Slandard half-cell that is used to measure the EMF of the turbidity. For a given Ore concentrate, Nokes reagent, and a given type of Staiidard half-cell, however, is the EMF of the pulp essentially reproducible from sample to sample. Also in such cases is the approximate EMF value the turbidity in which the Nokes reagent loses its ability to depress copper minerals appears to be roughly the same from sample to sample, and this approximate EMF value can be empirical for any given ore concentrate, Nokes reagent, and any given standard half-cell by known methods be predetermined. For example, if a chalcopyrite made of twin-buttes ore Copper concentrate is conditioned with Anamol "D", a commercially available Nokes-type reagent, the reagent appears to lose its ability to depress copper minerals when the EMF of the flotation pulp drops to about -200 mV to -250 mV, measured with a platinum electrode in relation to a normal GP (calomel) glass electrode.

example 1

A series of flotation experiments was carried out made with freshly made twin-buttes copper concentrates that contain approximately 31.9% copper and 0.51% Contained molybdenum for extraction of a crude molybdenite concentrate using anamol "D", a Nokes-type reagent, used as a pushing agent for copper minerals. A single serving of the ore concentrate was divided into four equal samples with an average weight of approx. 740 g. Every sample (called here sample A, B, C and D) was with the same collector for molybdenite and with a different one Amount of the aforementioned Nokes-type press center! conditioned for copper. These conditioned Flotation samples are described in Table 1.

Table 1

sample sample Mnlybdänii- Kuplcr- Initial weight Siimmlcr ilrückniiUel IiMk (m V) (G) (kg / ton) (kg / ton) negative A. 750 0.236 3.42 - 460 B. 730 0.242 3.48 - 520 C. 750 0.236 4.9 - 560 D. 733 0.241 7.49 - 610

Each conditioned sample was then placed in a normal laboratory flotation machine for a total of 16 minutes long subjected to froth flotation using air as a frothing gas. the The EMF of the conditioned flotation pulp produced from each sample became just prior to the start of each Flotation experiment determined and then at two-minute intervals during the duration of the experiment. The foam concentrate was also collected at two minute intervals and its mineral content weighed and examined. On the linde of each experiment, the residues were collected and their mineral content weighed and examined. The results of these four flotation experiments are in Table 2 explains.

Table 2

Flotation history tests A, B, C and D show the effectiveness of Anamol "D" (a Nokes-type reagent; at different concentrations with respect to time and give the decomposition when reading the mV level from Anamol »D« when using air as the foaming gas.

weight

the

Products

Cu mineral

Wt%

Examined products

Cu Mo

Cum. distribution
Cu Mo

Reading after rotation

(mV)

Test, sample A (2.424 kg / t (5.34 lbs / t) anamol "D"; mV reading at time 0 [start of flotation] = -460)

Mo raw 25th concentrate 75 0-2 min. 128 2-4 min. 133 4- 6 min. 144 6- 8 min. 107 8-10 min. 44 10-12 min. 20th 12-14 min. 14-16 min. Mo raw 74 Residue 0-16 min.

3.33 13.30 30.40 48.10 67.30 81.70 87.50 90.20

9.80

18.25 16.21 1.93 70.11 26.63 1.53 10.37 89.96 32.26 0.204 27.82 94.48 33.77 0.080 46.80 96.32 34.62 0.050 67.87 97.57 34.64 0.048 83.53 98.45 33.14 0.054 89.69 98.86 30.88 0.070 92.30 99.11

-220

-160

-140

-120

-100

-90

-80

-70

24.65 0.070

7.70

0.89

Example Il

A second series of FloUitionsexperi- sample was made with the same molybdenite collection ments with similar freshly made twin-buttes-45 conditioned and with a different sized, rc

Copper concentrates carried out, whereby a single portion of the ore concentrate was divided into two identical samples (here designated as samples E and F) with an average weight of approx. 510 g. Every

Table 3

relatively small amount of Anamol "D", the Nokes type copper pusher. These conditioned flotation samples are listed in Table 3 .

sample sample Molybdenite Copper- Beginning
lich emf weight Collector Pusher kg / t kg / t (mV) (G) (lbs / t) (lbs / t) 0.35 1.7 -370 E. 527 (0.76) (3.8) 0.37 2.9 -360 F. 493 (0.81) 6.5

Each conditioned sample was then subjected to froth flotation in the same laboratory flotation machine for a total of 16 minutes using nitrogen as the frothing medium. The emf of the fiotation slurry was measured and the upstream flotation was collected and tested as in Example. At the end of each flotation experiment the underflow was collected and tested as before. The results of these two flotation experiments are shown in Table 4

Io

Table 4

Flotationsverlaul'slests E and F show the effectiveness of Anamol "I)" with relatively low concentrations when using StickstolT as a foam-forming cias instead of air.

weight
the

Products
G

Cu mineral

Gcw.-Vo

Conc.

Examined products

Cu

("um. distribution

Cu

Mon

Reading after flotation

(mV)

Test, sample E (1.72 kg / t (3.8 lbs / t) anamol "D"; mV separation at start of flotation = -370)

Mo raw concentrate

0-2 min.

2-4 min.

4- 6 min.

6- 8 min.

8-10 min.
10-12 min.
12-14 min.
14-16 min.

Mo pipe residue

0-16 min.

29
13th

5
3
3
3
2
3

466

5.50

7.96

8.91

9.48

10.05

10.62

11.00

11.57

3.43

7.58 6.74 8.88 4.35 12.02 2.49 15.04 1.52 20.78 0.67 22.30 0.48 23.91 0.35 24.44 0.30

1.47 67.86 2.24 87.49 2.64 91.81 2.94 93.39 3.36 94.09 3.80 94.59 4.12 94.83 4.61 95.15

-260

30.67

0.03

95.39

4.85

The results of the flotation experiments described in Examples I and II are shown in FIG. 1 and 2 of the drawing are graphically compiled and shown.

Fig. 1 shows the effectiveness of various Anamol "D" concentrations as copper depressant in relation to the time (duration of flotation) when air and nitrogen are used as the foaming gas will.

Figure 2 shows the steady decrease in EMF and pushing effect of the Nokes reagent on copper minerals in the flotation turbidity when air is used as the foaming gas, compared to the relatively constant EMF and effective pushing of copper minerals in the slurry when nitrogen is added is used for this purpose.

It can be seen from Figure 1 that with air as the foaming gas, the percentage of copper pressed with respect to time is a function of the Nokes reagent amount or concentration initially present in the flotation pulp of depressed copper is very high for a period of time, depending on the initial Nokes reagent concentration, until the reagent appears to lose its ability to depress copper minerals rather abruptly, whereupon the percentage of depressed copper minerals drops significantly when the foaming gas is nitrogen is, keep

; <5 the Nokes reagent on the other hand its ability to copper to push minerals during flotation without noticeable deterioration. Is particularly significant the fact that when using an inert gas; as foaming agent, the amount of Nokes reagent which

-to for achieving and maintaining a very high Degree of copper pressing is necessary, mean c is less than that when using air al:

foaming gas required amount.

From Fig. 2 it can be to the flotation be using air as foaming agents and de relatively stable emf easily recognize the pulp when used before nitrogen as foaming gas the contrast between derr rapid decline of the EMF Similarly, the relationship between the electromotive force of the pulp and is mentioned abrupt loss of the ability to push de: Nokes reagent.

For this purpose 2 sheets of drawings

Claims (3)

Patent claims: 1. Process for the selective flotation of molybdenum sulfide from molybdenum-containing copper concentrates, in the case of copper sulfide with the help of reaction products, the divalent sulfur and a Alkali or alkaline earth ions, phosphorus, arsenic or antimony (Nokes-type pushers) are contained in the aqueous turbidity remains printed, thereby ge ίο indicates that an inert gas is used to form bubbles used and the EMF of the aqueous slurry is kept above about - 200 mV. 2. The method according to claim 1, characterized in that the maintenance of the EMF above approx. - 200 mV by adding the button for copper sulfide 3. The method according to claim 1, characterized in that the bubble or foam generation with inert gases such as nitrogen, freon, possibly also mixed with one another and with other inert gases, he follows.