Copper sulfide ore flotation general process

Press to various other useful components, copper sulfide ore can be classified as follows:

(1) Single copper ore. Its ore is relatively simple, and the only valuable component that can be recycled is copper. The gangue is mainly quartz , silicates and carbonates.

(2) Copper sulfide ore. In addition to copper minerals, this ore can also be recovered from iron sulfide minerals. The main mineral of sulfur is pyrite. This ore is called copper-bearing pyrite.

(3) Copper pyrite . In addition to copper minerals and pyrite, the ore can be recycled, and magnetite is worth recovering.

(4) Copper- molybdenum ore. The useful component of this ore contains molybdenite in addition to copper minerals. In addition to copper and molybdenum, some ore can still be recovered from magnetite and pyrite.

(5) Copper- nickel ore. In addition to copper minerals, there are nickel-containing minerals such as nickel sulfide ore and nickel-containing pyrite and pyrrhotite.

(6) Copper- cobalt ore. In addition to copper minerals, there are also cobalt-containing pyrite. The latter is selected as the cobalt concentrate.

Major copper sulfide minerals, iron minerals and their floatability

Chalcopyrite (CuFeS2) contains Cu 4.55% and is the main copper mineral. Chalcopyrite can maintain its natural floatability in neutral and weakly alkaline media for a long time, but in strong alkaline (pH>10) medium, iron hydroxide film is formed due to OH-etching of surface structure. Its natural floatability is reduced. The chalcopyrite in the surface layer of the deposit is oxidized for a long time, the hardness is small, and it is easy to be pulverized, so its floatability is deteriorated.

The most commonly used collectors for flotation chalcopyrite are xanthate and black medicine. Sulfur nitrogens and thiamine esters have also been used in recent years. In foreign countries, people have used isothiouronium salts, butylene esters, etc. to replace xanthate flotation chalcopyrite.

Chalcopyrite is susceptible to inhibition by cyanide and oxidants in alkaline media. For example, in the separation of copper and lead , cyanide is commonly used to inhibit chalcopyrite; in the case of separation of copper and molybdenum, the use of an oxidizing agent to suppress chalcopyrite has been widely used. The inhibited chalcopyrite is sometimes activated with a copper salt such as copper sulfate.

The copper ore (Cu2S) contains 79.8% of Cu, which is the most common secondary copper sulfide mineral. It is brittle and easy to be crushed and muddy. The copper minerals of many large porphyry copper deposits abroad are chalcopyrite. The collector of chalcopyrite is mainly xanthate. It has good floatability in both acidic and alkaline media. Since the crystal lattice energy of copper-sulfur crystals in the chalcopyrite is small, the copper ion radius is small, the sulfur ion radius is large, and the exposure is easily oxidized, the chalcopyrite is more oxidized than the chalcopyrite. After oxidation, more copper ions enter the slurry. The presence of these copper ions can activate other minerals or consume chemicals, making sorting difficult.

The inhibitors of chalcopyrite are Na2S03, Na2S203, K3Fe(CN)6 and K4Fe(CN)6, and a large amount of Na2S also inhibits chalcopyrite. The inhibitory effect of cyanide on chalcopyrite is weak because the copper ions on the surface of the chalcopyrite are continuously dissolved and react with cyanide, thus causing cyanide to fail. Only by continuously adding cyanide can the purpose of inhibition be achieved.

The chemical composition of the copper ore (Cu5FeS4) is not fixed. It contains 63.3% Cu according to the formula, and there are two kinds of primary and secondary. The surface properties and floatability of the porphyrite are between the chalcopyrite and the chalcopyrite. When xanthate is used as a collector, it can float in both acidic and weakly alkaline media. When pH>10, its floatability decreases. In a strongly acidic medium, its floatability is also significantly deteriorated, and it is easily inhibited by cyanide.

Other copper sulfide minerals, such as copper blue (CuS), are similar in floatability to chalcopyrite. Arsenic bismuth copper ore 3Cu2S·As2S3 is a primary copper ore. It is an equiaxed crystal system, does not dissociate in fact, has many isomers, has low hardness, high brittleness, and is easy to overgrind. When flocculating arsenic bismuth copper ore with butyl sulphate, the optimum pH is 11-12. The medium adjuster uses sodium carbonate better than lime because it has an inhibitory effect on arsenic bismuth copper ore when the free CaO is higher than 400 g/m3. When the amount of sodium sulfide is low (30 mg/L), the oxidized surface can be cured to improve the floatability, but the amount of the sulfide can be completely inhibited from flotation of the arsenic bismuth copper ore.

For the floatability of copper sulfide minerals, the following rules can be summarized:

(1) All iron-free minerals, such as chalcopyrite and copper blue, have similar buoyancy, and cyanide and lime have weaker inhibition effects on them.

(2) Any copper mineral containing iron, such as chalcopyrite or porphyrite, is susceptible to inhibition by cyanide and lime in an alkaline medium.

(3) The xanthate collector mainly chemically adsorbs with the cationic Cu2+, so the surface contains more Cu2+ minerals and has stronger effect with xanthate. The order of strength is: chalcopyrite > copper blue > porphyrite > chalcopyrite.

(4) The floatability of copper sulfide minerals is also affected by factors such as crystal size, embedded grain size and primary and secondary properties. Crystallization and inlaying are too thin to be difficult to float. Secondary copper sulfide ore is easily oxidized and is less likely to float than primary copper ore.

Almost all copper sulfide ore has iron-containing sulfides, so in a sense, the flotation of copper sulfide ore is essentially the separation of copper sulfide from iron sulfide. The iron sulfide minerals commonly found in copper ore are pyrite and pyrrhotite.

Pyrite (FeS2) contains S53.4% ​​and is widely distributed in sulfide ore, almost all kinds of deposits. Since pyrite is the main raw material for the production of sulfuric acid, it is customary to refer to the pyrite concentrate as a sulfur concentrate.

Pyrite can be used as a collector in acidic, neutral and weakly alkaline pulps. Pyrite treated with acid (sulfuric acid, hydrochloric acid) is very buoyant (pH = 4.5 is best when using xanthate). In weak alkaline pulps with a pH of 7-8, the use of xanthate for harvesting is also an economically efficient method. For the recovery of pyrite, black medicine is weaker than yellow medicine.

The inhibitors of pyrite are cyanide and lime. Chalcopyrite, sphalerite and pyrite separation, mainly as pyrite with lime inhibitor. The inhibited pyrite can be activated by lowering the pH with sulfuric acid, and can also be activated by sodium carbonate or carbon dioxide. Copper sulfate is often added during activation.

Pyrrhotite (Fe5S6~Fe16S17) generally has a lower sulphur content than pyrite. It is easy to oxidize and muddy, and it is a harder to float iron sulfide mineral.

In the alkaline and weakly acidic pulp, the floating magnetic pyrite should be activated by Cu2+ ions or activated with a small amount of sodium sulfide, and then harvested with advanced yellow drug.

Inhibitors of pyrrhotite include lime, cyanide and sodium carbonate. In special cases, potassium permanganate can be used, such as arsenopyrite or when pentlandite and pyrrhotite separation, potassium permanganate suppressed pyrrhotite and arsenopyrite activation with sodium sulfide or copper sulfate, nickel Pyrite.

When pyrrhotite is oxidized in the slurry, it consumes oxygen in the slurry. The oxygen in the slurry is very important for the flotation of sulfide ore. When there is pyrrhotite in the ore, the other sulfide minerals are floated with xanthate. Before the reaction between oxygen and pyrrhotite, other sulfide ore does not float, and only the remaining oxygen in the slurry causes partial oxidation of other sulfide ore surfaces. In order to make them float. Therefore, when there is a sulfide ore flotation in the ore, it is very important to adjust the aeration of the slurry.

Activators of pyrrhotite, as well as copper sulfate plus sodium sulfide, sodium fluorosilicate and oxalic acid. In China's skarn type copper ore, a large part of the sulfur-bearing minerals are pyrrhotite. Since pyrrhotite is not easy to float and has magnetic properties and is contained in magnetic iron concentrate, it is the main cause of high sulfur content in iron concentrate.

The chemical composition of pyrite (FeS2) is the same as that of pyrite, but the crystals are different. Pyrite is an equiaxed crystal system and pyrite is an orthorhombic system.

The pyrite flotation is similar to pyrite, but better than pyrite. The order of buoyancy of several kinds of iron sulfide ore collected by xanthate is: pyrite > pyrite > pyrrhotite.

Copper-sulfur ore flotation

Copper-sulfur ore is one of the major copper deposit types in China. Its deposits are mostly copper-bearing pyrite deposits and copper-bearing skarn deposits, which are widely distributed. Gansu silver as white, Hubei Daye, Tongling, Anhui, Jiangxi Yongping; Wushan, Hebei and other regions have such deposits. Copper-sulfur ore has two types of dense copper-bearing pyrite and disseminated copper-bearing pyrite. The former has a high content of pyrite and the latter has a low content of pyrite. Flotation of this ore in addition to the recovery of copper sulfide, but also the recovery of iron sulfide as a sulfur concentrate.

The main factors affecting the flotation of copper-bearing pyrite are:

(1) The grain size and symbiotic relationship of copper and iron sulfide. Generally, the pyrite content of the pyrite is relatively coarse, while the copper mineral, especially the secondary copper sulfide ore, is closely related to the pyrite, and it is necessary to grind to a relatively fine time to dissociate the copper mineral from the pyrite. This feature can be utilized. The copper-sulfur mixed concentrate is selected, the tailings are discarded, and the mixed concentrate is reground and separated.

(2) The influence of secondary copper sulfide minerals. When the content of secondary copper sulfide mineral is high, the increase of copper ions in the pulp will activate the pyrite and increase the difficulty of separating copper and sulfur.

(3) The influence of pyrrhotite. High pyrrhotite content will affect the flotation of copper sulfide minerals. The pyrrhotite oxidizes and consumes oxygen in the slurry. In severe cases, the copper mineral does not float at the beginning of the flotation. Inflation can be enhanced to improve this situation.

A copper-sulfur ore flotation process

There are three common flotation processes:

(1) Priority flotation. Generally, the copper is floated first, and then the sulfur is floated. Tight block-like copper-bearing pyrite, the content of pyrite in the ore is quite high, and the use of high alkalinity (free CaO content>600-800g/m3) and high-yellow medicinal amount float copper to inhibit pyrite. The tailings are mainly pyrite, and there are few gangues, so the tailings are sulfur concentrates. For the disseminated copper-sulfur ore, the preferential flotation process is adopted. The tailings after the floating copper should be floated again. In order to reduce the consumption of sulfuric acid during the floating sulfur and ensure safe operation, the low alkalinity process conditions should be used when floating copper.

(2) Mixing-separation flotation. For the copper ore ore with low sulfur content in the ore and copper minerals which are easy to float, it is advantageous to use this process. The copper-sulfur minerals are first mixed flotation in the weakly alkaline pulp, and the mixed concentrate is added with lime to separate the copper and sulfur in the high alkaline pulp.

(3) Semi-priority mixing-separation flotation. Semi-priority mixing-separation flotation is a collector with semi-priority floating copper operation with selective selectivity of Z-200 or OSN-43, ester-105, etc., first floats out of the easily floating copper mineral, and is partially qualified. The copper concentrate is then subjected to copper-sulfur mixed flotation, and the obtained copper-sulfur mixed concentrate is separated and floated by using float copper to suppress sulfur. This separation process avoids the inhibition of easy-floating copper minerals under high lime dosage and does not require the consumption of large amounts of sulfuric acid to activate pyrite. The production practice shows that the process structure is reasonable, the operation is stable, the index is good, and the characteristics of the target mineral are recovered as early as possible.

As far as the grinding and floating process is concerned, for the refractory copper ore, it is more advantageous to adopt the stage grinding and floating process, such as re-grinding of coarse concentrate, re-separation of mixed concentrate, re-separation of refinery, re-grinding by medium-mine, etc. Adopted by domestic and foreign selection plants.

B copper sulfur separation method

Regardless of the process used for copper-sulfur ore, there is a problem of separation of copper and sulfur. The principle of separation is generally that copper is used to suppress sulfur, that is, to inhibit pyrite.

(1) Lime method. The use of lime to inhibit pyrite is a common method for the separation of copper and sulfur. When the lime and sulfur method is used for the separation of copper and sulfur, the pH value of the pulp or the free CaO content in the slurry can significantly affect the separation effect. The general rule is that when dealing with dense lump ore with a large amount of pyrite, a large amount of lime is needed to make the free CaO content in the slurry reach 800 g/m3 to inhibit pyrite. For mines containing less pyrite, the use of lime to control the 0H value of the slurry at 9 to 12 can float copper to suppress sulfur. Sometimes, in order to avoid the problem of “running trough” and concentrate difficult to handle due to excessive lime consumption, a small amount of cyanide may be added or an ester collector with weak harvesting power for pyrite may be selected.

(2) Lime + sulfite method. This method is a widely used method for inhibiting pyrite without cyanide. For copper ore ore with high sulfur content or high sulfur content, but high mud content, or high pyrite activity and not easily inhibited by lime, lime and sulfite can be used to inhibit pyrite separation of copper and sulfur. . The key to this method is to control the appropriate pulp pH and the amount of sulfite (or SO2) according to the nature of the ore, and pay attention to the appropriate aeration and agitation. Some experimental studies have pointed out that in the weakly acidic medium with pH=6.5~7, it is more effective to inhibit pyrite by using lime and sulfite method. Compared with the lime method, the lime plus sulfite method has the advantages of stable operation, good copper index, and low amount of activator such as sulfuric acid.

(3) Lime + cyanide method. For pyrite with large floating activity, inhibition by lime and cyanide is effective, but since cyanide is toxic, it will pollute the environment, so people try to replace it with lime and sulfite.

In the copper-sulfur separation flotation, the use of a selective collector can not only reduce the amount of inhibitors and activators, but also stabilize the operation.

C copper sulfur ore flotation example

Metamorphic volcanic deposit belongs to a system of multi-pyrite metal deposit, more complex ore types, can be divided according to the structure configured disseminated, dense block, semi-block are three main previously two kinds.

The main metal minerals are pyrite, chalcopyrite, copper blue, chalcopyrite and sphalerite. The content of pyrite in the massive ore accounts for more than 85%. The main gangue minerals are quartz, chlorite and sericite. The useful mineral structure is complex and the inlay relationship is various, but the relationship between the main metal minerals and the gangue is relatively simple. Copper minerals are medium-fine grain inlays. Pyrite is often produced by self-formed crystals, semi-automorphic crystals and granular aggregates. The inlaid grain size is between 0.1 and 0.5 mm, and some are densely symbiotic with chalcopyrite.

The dressing stone according to massive copper pyrites, disseminated massive copper-zinc ores and copper sulfur pyrites three categories, each with a different sorting process and conditions. This section only describes the flotation method for copper-sulfur ore.

The massive copper-bearing pyrite ore is continuously ground to 80%-0.074mm in two stages for flotation (one coarse and one sweep), using lime as an inhibitor of pyrite, in high alkalinity (including free Under CaOS00~1000g/m3), copper is floated with butyl xanthate and pine oil, and the tailings are sulfur concentrate.

When the disseminated copper-sulfur ore is treated simultaneously with the massive copper-bearing pyrite, the plant adopts the “mineralization method” to treat the two types of ore: that is, under the condition of low alkalinity (including free Ca050-100g/m3) pulp, Selecting copper-sulfur mixed concentrate from disseminated copper ore, adding grinding ore operation to massive ore, separating copper and sulfur together with massive ore under high alkalinity ore, selecting copper concentrate and sulfur Concentrate. From the analysis of process effects, it has the essence of branching. Its main features are simple process, convenient operation and saving of medicine.

Sometimes a single disseminated copper-sulfur ore is treated with a low calcium, low-yield (depletion dosing) preferential flotation refining process.

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