Research on Fine Particle Flotation Process
The interaction between particles plays an important role in the selective coagulation and dispersion of fine-grained minerals and the adhesion of mineral particles to bubbles. The interaction between similar particles affects the process of flotation, selective flocculation and hydrophobic condensation of self-generated carriers, while the interaction between heterogeneous particles affects the flotation of heterogeneous carriers, oil agglomeration and the adhesion process of mineral particles and bubbles. The interaction between heterogeneous ore particles and similar particles is obviously different. Van der Waals force between the same kind of particles is always gravitational force, electrostatic force is always repulsive force, and van der Waals force and electrostatic force between heterogeneous particles can be gravitational force or repulsion, which depends on In the nature of the system.
Mineral pulp fines floating force complicated system of various interfaces, by its research, may be selectively hydrophobic agglomeration of mineral particles to increase its "apparent particle size", thus reinforcing each other hydrophobic mineral particles and bubbles Act to adapt it to the conventional flotation process. There are many types of fine flotation, such as shear flocculation flotation, carrier flotation, emulsification flotation, and the like.
Selective flocculation flotation that selectively increases the "apparent particle size" of hydrophobic ore by bridging the polymer, which is divided into two types: selective flocculation direct flotation and selective flocculation de-flocation. JE Gai Bate and Wells D. W- Brentano rich iron ore and to hand mixing red quartz ore flotation studies conducted direct selective flocculation, i.e. first with polyacrylic acid (PAA) is smaller than the diameter of the flocculated fine particles of hematite lum Then, positive flotation was carried out with sodium dodecyl sulfate (SDS). The largest industrial application of flotation after selective flocculation and desliming is the United States Tilden Concentrator, which uses water glass as a dispersant, starch as a flocculant, and selective flocculation and desliming to carry out reverse flotation to increase the redness of 10-25 μm. The grade of iron ore concentrate. Shear coagulation flotation is the selective agglomeration of hydrophobic fine ore particles suspended in a surfactant solution by applying a sufficiently large shear field followed by conventional flotation. The shear flocculation flotation process has been successfully applied to the production practice of fine-grained scheelite flotation.
Rowling a hydrophobic agglomerate slurried technology, can significantly improve the degree of hydrophobicity of the surface of the mineral sericite, this technique surfactant, neutral mineral oil at a high speed stirring, the surfactant and shear mixing agglomeration, so that The particle size of the target mineral increases, forming agglomerates, and the degree of hydrophobicity increases, resulting in enhanced planktonic properties and a significant increase in flotation recovery. The hydrophobic flotation flotation has an increase of 10.74% compared with the conventional flotation recovery; the grade is reduced by 1.41%.
The silver sulfide sweep concentrate of the Fresneluo flotation plant, the largest silver concentrate manufacturer in Mexico, contains a large amount of silver sulfide minerals with a particle size of 1 to 25 μm. We have re-grinded and flocculated flotation tests. The scavenger concentrate ground to 80% -40μm, Aerophine 3418 used as collector, so that silver sulfide mineral hydrophobicity, hydrophobic flocculation enhancing silver sulfide grains and galena with coal and oil emulsion. The mechanical stirrer has a speed of 900 r/min and a stirring time of 10 min. The results of hydrophobic flocculation flotation are superior to conventional flotation. At the same silver recovery rate (60%), the concentrate grades obtained by flocculation flotation and conventional flotation were 30 kg/t and 25 kg/t, respectively. When the grade of concentrate silver is the same (30kg/t), the recovery rate of flocculated flotation concentrate silver is 9% higher than that of conventional flotation concentrate. For high grade concentrates, the indicators are more pronounced.
Carrier flotation refers to the addition of coarse particles of suitable particle size as a carrier in a fine-grain suspension system. Under the combined action of the collector and system kinetics, the fine-grained minerals are attached to the coarse-grained carrier and then subjected to conventional froth flotation. Recycling. According to different carriers, we can classify carrier flotation into heterogeneous carrier flotation and similar carrier flotation. By "heterogeneous carrier" is meant that the carrier is not the same mineral as the agglomerated fine mineral. Although the heterogeneous carrier flotation can obtain better indicators, but the disadvantages are also more: First, the amount of collector is larger; second, when the loaded mineral is a useful mineral, the preparation and separation of the carrier is difficult. These shortcomings severely limit the application prospects of this process. In general, heterogeneous carrier flotation is only suitable for use in the selection stage, ie removal of lesser amounts of gangue minerals, and requires that the carrier be less expensive or easier to recycle. The so-called "like carrier", that is, the carrier is the same type of mineral as the contained mineral. The sorting process is similar to the heterogeneous carrier flotation process. The separation of the fine-grained wolframite by the process shows that the concentrate grade and recovery of the fine-grained wolframite is compared with conventional flotation. The rate has been improved to some extent. Compared with heterogeneous carrier flotation, flotation of the same kind of carrier has the following two advantages: (1) eliminating the separation process of the carrier and its similar fine-grain minerals; 2 the selectivity of the carrier to the fine-grained minerals and the selective adsorption of the agent on the mineral Enhanced, which greatly improves the recovery rate and sorting efficiency of flotation operations.
In the 1960s, it was first used for the purification of kaolin . Wang and P. Somasundaran pointed out that the interaction between the oleic acid adsorption layers is the source of the aggregation of mineral particles and carriers. Qiu Guanzhou proposed the concept of coarse particle effect, which means that the coarse particles have the three effects of carrier, intermediate and anti-coagulation during fine flotation, thus strengthening the fine flotation.
Qiu Guanzhou et al. studied the carrier flotation of -5μm fractional wolframite and compared it with conventional flotation under the same conditions. The added bodies are different size grade wolframites larger than 10 μm. It was found that the addition of the coarse-grained carrier significantly improved the recovery of the -5 μm particle size, mainly because of the "collision-adsorption" between the hydrophobic particles under strong turbulent conditions, thereby increasing the fine-grained level. Flotation rate.
Liang Ruilu et al. used the same kind of mineral coarse-grained tin ore and heterogeneous mineral coarse-grainite (oxidized ore), galena (sulfurized ore) and quartz (hydrophilic mineral) as carriers, and sodium oleate as collector. Test to increase the recovery rate of fine grain tin ore. Whether it is a single sample test of fine-grained tin ore or a carrier flotation test, when the carrier is floated, the recovery rate of fine particles is much higher than that in the conventional flotation, and 48% in conventional flotation, the carrier At the time of flotation, it is 65% to 94%. The difference of the types of carriers is different for increasing the recovery rate of fine-grained tin ore. The order of increase is as follows: white lead ore > galena > tin ore > quartz. When the hydrophilic mineral quartz is used as the carrier, it is considered that the improvement of the recovery rate of the fine-grained tin ore is mainly caused by the shear aggregation and the aggregation promoting action of the coarse-grained quartz. When the flotation test is carried out under the conditions of different stirring speed, stirring time, carrier particle size, flotation time and other factors, the recovery rate of the coarse-grained porphyrite and coarse-grained tin ore is different, but the change trend is similar. When the pH value of the slurry and the ratio of the carrier are changed, the recovery rate of the fine particles is also different. In the carrier flotation test of a mixed sample of fine-grained tin ore and quartz, the grade of the coarse ore was slightly increased, and the recovery rate of the fine-grained tin ore was increased from 28% in the conventional flotation to 63% to 81%. In the flotation of the carrier, the proportion of tin ore of -5 μm in the slurry is 33% to 54% less than that of the conventional flotation, and the amount of reduction is exactly the same as the increase of the recovery rate of the fine particles. Moreover, at the time of carrier flotation, the rate constant of the carrier flotation is twice that of the conventional flotation (the coarse-grained tin ore is the carrier) and four times (the platinum ore is the carrier) due to the increase in the particle size of the particles. In summary, carrier flotation can be considered as one of the effective methods for recovering fine-grained tin ore.
Emulsified flotation is also known as agglomeration flotation. The non-polar oil is emulsified and dispersed, and the dispersed oil beads are used as a bridging medium to achieve agglomeration between the ore particles, and then separated by bubble flotation. It began in the 1950s, in addition to the process used in natural hydrophobic minerals, such as graphite, natural sulfur, molybdenite and coal, ore and manganese ore in terms of phosphorus existing industrial applications. Studies have shown that the use of collectors, neutral oils and a small amount of emulsifier in a certain way to prepare emulsion flotation fine particles, the effect is better than conventional flotation. For example, dodecylamine flotation of zinc oxide , the emulsion made of dodecylamine, kerosene and pine oil is better than the flotation effect of dodecylamine alone.
The kerosene collector is emulsified with DR emulsifier to form a uniform oil-water emulsion, which promotes the dispersion performance of kerosene in the slurry. The emulsifier has a plurality of ether groups which can simultaneously generate hydrogen chain adsorption with the hydrophilic oxygen-containing functional groups on the surface of the coal, thereby eliminating the influence of the oxygen-containing functional groups, and the surface of the coal is not allowed under the action of the non-polar group of the surfactant. The hydrophobicity of the flotation zone is increased, the hydrophobicity of the surface of the coal particles is increased, the coal preparation efficiency is improved, and the consumption of the collector is reduced.
The application of emulsification flotation has great economic significance and strong applicability to the Majiagou Mine Coal Preparation Plant. After the installation, construction and commissioning process of the flotation emulsification station is successful, the emulsification flotation makes the recovery rate of the clean coal more conventional. The flotation increased by 1.65%, the consumption of coal per ton decreased by about 25%, and the annual economic benefit exceeded 1.14×10 6 yuan.
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