At present, the flotation method is used in molybdenum beneficiation. The principle of flotation is to use the difference of mineral floatability to separate minerals from each other. That is, by adding flotation agents to change the physical and chemical properties of mineral surfaces, adjust the floatability of minerals or expand the difference in floatability between minerals to achieve the purpose of mineral sorting.
Types, properties and uses of molybdenum mineral processing reagents
The common chemicals used in molybdenum concentrator are collector, foaming agent, inhibitor, dispersant, etc. The selected aluminum collector is generally a polar collector of oil or oil-added xanthate; the foaming agent is generally 2# oil, miscellaneous alcohol or ether alcohol; the inhibitor is generally sodium thioglycolate, phosphorus Knox, etc., and the dispersant is generally water glass, sodium nitrogen silicate, etc.
1. Hydrocarbon oil collector
1.1.1 Properties of hydrocarbon oil collectors
Due to the good hydrophobicity of molybdenite, non-polar hydrocarbon oils such as hydrocarbon oil and diesel oil are selected as molybdenum collectors. Hydrocarbon oil is one of the petroleum series products and an important industrial fuel. Because the composition of hydrocarbon oil is complex and varies with the place of origin, the composition of hydrocarbon oil is also complex and is flammable. Its specific gravity is 0.76 ~ O.85 g/cm3. The specific gravity of hydrocarbon oil is related to its boiling point temperature. The higher the boiling point temperature, the greater the specific gravity. The specific gravity of the oil we currently use is 0.83g/cm3.
Hydrocarbon oils are low toxic and have a stimulating effect.
1.1.2 The role of hydrocarbon oil collectors.
Hydrocarbon oil is mainly used in the dry flotation surface is non-polar, natural hydrophobic, strong floatability of minerals.
Because the hydrocarbon oil is difficult to dissolve in water, in the production of molybdenum, the hydrocarbon oil is added to the ball mill, that is, to extend the time of oil and mineral action. Practice has proved that the oil emulsification will be added after the use of better results, not only can save the amount of use, but also improve the metal recovery rate of flotation.
Pay attention to the amount of hydrocarbon oil should not be too large, because when the amount of hydrocarbon oil is too large, first, it has defoaming effect, which is unfavorable to the selection index. The second is to cause high consumption and increase the beneficiation cost. Furthermore, the dehydration and drying of molybdenum concentrate of the final product brings difficulties, which is prone to fire and shooting accidents.
(2) Foaming agent 2# oil
1.2.1 2# oil properties
2# oil, also known as pine oil, brown yellow to dark brown oily liquid, the main component is terpene alcohol (C10 H17OH), insoluble in water, soluble in ethanol and other organic solvents. The product is low toxicity (mice oral LD50 = 6 000 mg/kg). Flammable, open flame, high temperature can cause combustion.
1.2.2 Effect of 2# oil
2# oil to promote air dispersion in the slurry, the formation of suitable size, good toughness, stable performance of the foam, for the purpose of mineral flotation to provide a carrier, to achieve the purpose of mineral separation.
(3) Inhibitor Phosphorus Knox
1.3.1 Nature of Phosphorus Knox
Phosphonox is the product of the reaction of P2S5 and NaOH. PhosphoKnox produces H2S, PH3 and small amounts of P2O5 during configuration and use.
P2S5 is gray to yellow-green crystal, with sulfide-like odor, flammable.
NaOH is a strong alkali, its solid is also known as caustic soda, caustic soda, caustic soda, etc., is a white solid, water absorption, easy deliquescence in the air; soluble in water, while releasing a lot of heat. There is a strong irritation and corrosive. H2S is a colorless gas, highly toxic, rotten egg smell, slightly heavier than air, can make the central nervous system poisoning.
PH3, also known as Teng, is a colorless gas, highly toxic, smelly smell of rotten fish, slightly heavier than air. P205 Irritating to human eyes, respiratory tract and skin. Large inhalations can cause dyspnea and even respiratory arrest.
1.3.2 The role of phosphorus Knox
Phosphorus Knox is used as a depressant in the flotation of aluminum ore, and its lead suppression effect is more significant. The ratio of P2Ss to NaOH was 1:1.3-1.7. The experimental results show that the mineral processing effect of this synthetic ratio is the best. The unit consumption is 20~50 g/t.
(4) sodium thioglycolate inhibitor
1.4.1 Sodium thioglycolate Properties
Sodium thioglycolate belongs to the sodium salt of thioglycolic acid, whose molecular formula is HSCH2COONa. The agent is clear, transparent, light green, with sulfide odor liquid. The primary product content of sodium thioglycolate (referring to the pharmaceutical agent currently used in the production site) is about 8.5, and the specific gravity of the liquid medicine is 1.25g/cm3.
Cu2, Fe2 and other heavy metal ions are catalysts that promote the oxidation of sodium mercaptoacetate, so contact should be avoided.
Sodium thioglycolate is a slightly alkaline agent with little irritation. The perming agent is a 9.0% sodium thioglycolate solution and is generally safe. Sodium thioglycolate is susceptible to air oxidation and does not cause toxic accumulation in the environment. That is, there is no pollution to the environment using the agent.
1.4.2 Effect of sodium thioglycolate
The inhibition effect of sodium thioglycolate on galena and chalcocite is better than that of sodium cyanide, which can replace sodium cyanide to inhibit copper, lead and other sulfide ores.
(5) Dispersant water glass, sodium fluosilicate
1.5.1 Properties of water glass
Water glass is an inorganic colloidal agent, which has a strong hydrolysis reaction, making the aqueous solution alkaline. So the use of water glass can adjust the pH value of the pulp.
The ratio of SiO2 and Na2O contained in water glass is called "modulus", and the "modulus" of water glass used in flotation is generally about 2.4. The smaller the modulus of water glass, the more soluble in water, but the inhibition ability is poor, and vice versa.
1.5.2 Use of water glass
Water glass is widely used in flotation. It is not only an inhibitor of quartz, silicate and other gangue minerals, but also a good slurry dispersant. It can also be used as a pH regulator for pulp and a good sedimentation aid.