7 factors affecting froth flotation process - jxsc machine
The full name of the flotation is called froth flotation. It is the process of selecting minerals from the pulp by means of the buoyancy of the bubbles, depending on the difference in the surface properties of the various minerals. Where to buy flotation machines?
The specific process of flotation is to add various flotation reagents to a certain concentration of slurry, and a large number of diffuse bubbles are generated by stirring and aeration in the flotation machine. At this time, the suspended ore collides with the bubbles, and some of The floatable ore particles adhere to the bubbles, and float up to the surface of the ore to form a foam product, which is the concentrate; the non-floating mineral remains in the slurry and becomes the tailings. Thereby, achieve the purpose of mineral sorting.
Froth Flotation machine plays an indispensable role in the mineral beneficiation process, flotation is susceptible to a number of factors during the process, including grinding fineness, slurry concentration, pulp pH, pharmaceutical system, aeration and agitation, flotation time, water quality and other process factors. The factors that affect the flotation process are detailed below.
Both large ore particles (larger than 0.1mm) and small ore particles (less than 0.006mm) affect flotation efficiency and mineral recovery. In the case of flotation coarse particles, due to the heavyweight, it is not easy to suspend in the flotation machine, and the chance of collision with the bubbles is reduced. Further, after the coarse particles adhere to the air bubbles, they are easily detached from the air bubbles due to the large dropout force. Therefore, the coarse particles have a poor flotation effect under the general process conditions.
During the fine particles flotation separation process, the fine particles are small in volume and the possibility of collision with the bubbles is small. The fine grain quality is small, and when it collides with the bubble, it is difficult to overcome the resistance of the hydration layer between the ore particle and the bubble, and it is difficult to adhere to the bubble.
The content of the coarse-grained monomer must be less than the upper limit of the particle size of the mineral flotation. At present, the upper limit of flotation particle size is generally 0.25-0.3 mm for sulfide minerals; 0.5-1 mm for natural sulfur; and the upper limit of particle size for coal is 1-2 mm.3.Avoid muddy as much as possible. When the flotation particle size is less than 0.01 mm, the flotation index will decay significantly.
The most appropriate grinding fineness must be determined by testing and reference to production practice data. For some ores, the stage grinding and stage selection process are often used to avoid over-grinding of the ore, so that the dissociated ore particles are selected in time.
If the froth machine contains much ore slurry, it will bring a series of adverse effects on flotation cells mineral processing. The main influences are as follows 1 Easy to be mixed in the foam product, so that the concentrate grade is reduced. 2 Easy to cover the coarse grain surface, affecting the flotation of coarse particles. 3 Adsorption of a large number of agents, increase drug consumption. 4 The pulp is sticky and the aeration conditions are deteriorated.
The type and quantity of the agent added during the flotation process, the dosing place and the dosing method are collectively referred to as the drug system, also known as the prescription. It has a major impact on flotation indicators.
In the ore dressing, it is necessary to pass the ore selectivity test in order to determine the type and quantity of the agent, and in practice, the number, location and mode of dosing should be constantly revised and improved.
In addition to oxygen, nitrogen and inert gases, there are carbon dioxide and water vapor in the air. The gas has a selective effect on the surface of the mineral, oxygen is the most important factor affecting the surface of minerals. Oxygen is beneficial to the hydrophobicity of sulphide ores/ sulfine flotation, however, if the action time is too long, the mineral surface will return to hydrophilicity. When the gas adsorption conditions are appropriate, the mineral surface will be drained, the flotation mineral processing can be done even without a flotation agent. The Galena mine can only float up with the action of xanthate through the initial action of oxygen.
Stirring the slurry can promote the suspension of the ore particles and evenly disperse in the tank, thus promote the good dispersion of the air and make it evenly distributed in the tank, further can promote the enhanced dissolution of air in the high-pressure area of the tank, and strengthen the precipitation in the low-pressure area. Enhanced aeration and agitation are advantageous for flotation separation, but not excessively, as excessive aeration and agitation can have the following disadvantages: (1) Promoted the merger of bubbles (2) Reduced concentrate quality (3) Increased power consumption (4) Increased wear of various parts of the flotation machine (5) The volume of the slurry in the tank is reduced (this is because the volume of the tank is increased by the portion occupied by the bubble) (6) Excessive agitation may also cause the ore particles attached to the bubbles to fall off. The optimum amount of aeration and agitation in production should be determined by experimentation depending on the type and structural characteristics of the flotation machine.
Inflation and agitation are carried out simultaneous in the flotation machine. Strengthening them is beneficial to increase the flotation index, but if it is determined too much, it will cause shortcomings such as bubble merger, degraded quality, increased electric energy consumption, and mechanical wear. Therefore, aeration and agitation must be appropriate.
The slurry concentration can affect the following technical and economic indicators: (1) Recovery rate. When the slurry concentration is small, the recovery rate is low. As the concentration of the slurry increases, the recovery rate also increases, but the recovery rate exceeds the limit. The main reason is that the concentration is too high, which destroys the aeration condition of the flotation machine. (2) Quality of concentrates. The general rule is that the quality of the concentrate is higher in the flotation of the leaner slurry, and the quality of the concentrate is reduced in the flotation of the richer slurry. (3) Consumption of pharmaceuticals. When the slurry is thicker, the amount of treatment per ton of ore is less, and when the concentration of the slurry is thinner, the amount of treatment per ton of ore is increased. (4) The production capacity of the flotation equipment. As the concentration of the slurry increases, the production capacity of the froth flotation machine calculated according to the treatment amount also increases. (5) Water and electricity consumption. The thicker the pulp, the smaller the water and electricity consumption per ton of ore processed. In short, when the concentration of the slurry is thick, it is beneficial to the flotation process. However, if the slurry and bubbles do not flow freely, the aeration will deteriorate, thereby reducing the quality and recovery. In this case, the various ore sections of the flotation should determine the appropriate concentration of the slurry according to the nature of the ore and relevant technical requirements.
The most suitable ore pulp concentration during the flotation process is related to the ore property and the flotation processing conditions. The general rules as flow: (1) Pulp Density. The mineral with large flotation density uses a thicker slurry, while the mineral with a small flotation density uses a thinner slurry. Flotation of coarse-grained materials with thicker slurry, flotation of fine-grained and muddy materials with thinner ore. (2) Pulp PH Value. The pH of the pulp refers to the concentration of OH and H+ in the slurry, which is generally expressed by the PH value. Various minerals have a floating and non-floating pH when using different flotation agents for flotation, The pH of the critical pH. By controlling the critical pH, it is possible to control the effective sorting of various minerals. Therefore, controlling the pH value of the slurry is one of the important measures to control the flotation process. (3) Flotation Time. The flotation time directly affects the quality of the indicator. The time is too long, the grade of the concentrate is reduced; the time is too short and the grade of the tailings is increased. Therefore, the flotation time required for various Minerals must be determined by experimentation. (4) Water Quality. Floating water should not contain a large number of suspended particulates, nor can it contains soluble substances and various microorganisms that may interact with minerals or flotation reagents. This problem should be specially noticed when using backwater, pit water, and lake water. (5) Pulp Temperature. Flotation is generally carried out at room temperature, but sometimes it is necessary to warm the slurry in order to obtain a good sorting effect. The specific heating or not needs to be determined according to the actual situation. If it is heated, it is best to adapt to local conditions and use waste heat and exhaust gas as much as possible.
The main effects of pulp quality score on froth flotation process in metallurgy are as follows: (1) Recovery rate. Within a certain range, when the pulp mass fraction is low, the recovery rate is low; the pulp mass fraction is increased, and the recovery rate is correspondingly increased. However, the mass fraction of the slurry should not be too large. If it is too large, the flotation machine is difficult to inflate normally in the slurry, which in turn reduces the recovery rate.
(2) Concentrate grade. The general rule is that the concentrate grade is higher when ore flotation is carried out in a leaner slurry, while the concentrate grade is reduced when it is floated in a thicker slurry.
(3) The dosage of the agent. The flotation agent should maintain a certain mass fraction in the pulp to have a good flotation effect. When the pulp is thicker, the mass fraction of the medicament is correspondingly increased, that is, the required medicament mass fraction can be achieved with fewer chemicals, and the amount of medicament per tan ore is correspondingly reduced. Conversely, when the pulp is thinner, the amount of the agent increases.
Thats all 7 main variables affecting froth flotation. Contact us to know more info about industrial gold mining equipment, get free froth flotation PDF, flotation process flow chart, and related industry cases of gold froth flotation, zinc froth flotation, copper flotation, ore flotation.
Since the content of useful components in the ore that needs flotation treatment is getting lower and lower, the particle size of the impregnation is getting finer and finer, and the composition is more and more complicated and difficult to separate. Therefore, how to design an efficient mineral flotation flow is of the utmost importance.
investigation on the influence of surface roughness on magnetite flotation from the view of both particle-particle and bubble-particle interactions - sciencedirect
It is well known that surface roughness of mineral particles has a significant influence on their flotation behaviors. In this investigation, magnetite was ground in rod and ball mills to generate particles with similar dimension and shape but varying degree of surface roughness, which was quantified using Atomic Force Microscopy (AFM). The influence of surface roughness on the floatability of magnetite particles was performed by flotation tests using an XFG flotation machine. Flotation tests indicated magnetite particles possessed higher surface roughness had higher flotation recovery and larger flotation rate constant. The aggregation behaviors of different rough magnetite particles were compared for the first time via an optical microscopy. Results of the optical microscopic tests revealed that there were a large number of aggregations in the system of particles with higher surface roughness. A proposed model was deduced with the parameters carefully calculated (not arbitrarily selected) to analyze the bubble-particle interaction energy using an Extended DVLO (DerjaguinLandauVerweyOverbeek) theory. The theoretical interaction energy points to lowering energy barrier when magnetite particles are covered with 28.03nm asperities as compared to 9.47nm asperities. The effect of surface roughness on mineral flotation was investigated from the view of both particle aggregations and energy barrier of bubble-particle attachment for the first time, which are the primary causes for differences in flotation performance.
the importance of mechanical scrubbing in magnetite-concentrate reverse-flotation - sciencedirect
The coating of fine magnetic particle on coarse silica is very likely to occur.The coagulation of fine magnetic particle is very likely to occur in neutral pH.Scrubbing improves magnetic-concentrate reverse-flotation performance efficiently.(NaPO3)6 can lower concentrate Fe recovery.Magnetic concentrate of 67.9% Fe grade and 71.5% Fe recovery was obtained.
Getting magnetite concentrate with extremely high Fe grade using reverse flotation method has become increasingly important due to the enhanced requirement of iron making industry. The coagulation in magnetite-concentrate flotation system may impose negative effect on flotation performance. This paper combined the DLVO calculation and microscope observation to study the coagulation behavior in the system. The result shows that the coagulation between fine magnetite and coarse silica particle is very likely to occur with energy barrier 1.51018J at pH 10.0, which is much smaller than 1.61017J and 3.31017J for fine magnetite and fine magnetite-coarse magnetite particles. The coating of fine magnetite particle on silica surface was observed under microscope. Mechanical scrubbing increases the concentrate Fe grade and recovery by 1.5% and 8.5% respectively. Magnetite concentrate of 67.9% Fe grade and 71.5% Fe recovery was finally obtained.
iron ore processing,crushing,grinding plant machine desgin&for sale | prominer (shanghai) mining technology co.,ltd
After crushing, grinding, magnetic separation, flotation, and gravity separation, etc., iron is gradually selected from the natural iron ore. The beneficiation process should be as efficient and simple as possible, such as the development of energy-saving equipment, and the best possible results with the most suitable process. In the iron ore beneficiation factory, the equipment investment, production cost, power consumption and steel consumption of crushing and grinding operations often account for the largest proportion. Therefore, the calculation and selection of crushing and grinding equipment and the quality of operation management are to a large extent determine the economic benefits of the beneficiation factory.
There are many types of iron ore, but mainly magnetite (Fe3O4) and hematite (Fe2O3) are used for iron production because magnetite and hematite have higher content of iron and easy to be upgraded to high grade for steel factories.
Due to the deformation of the geological properties, there would be some changes of the characteristics of the raw ore and sometimes magnetite, hematite, limonite as well as other types iron ore and veins are in symbiosis form. So mineralogy study on the forms, characteristics as well as liberation size are necessary before getting into the study of beneficiation technology.
1. Magnetite ore stage grinding-magnetic separation process
The stage grinding-magnetic separation process mainly utilizes the characteristics of magnetite that can be enriched under coarse grinding conditions, and at the same time, it can discharge the characteristics of single gangue, reducing the amount of grinding in the next stage.
In the process of continuous development and improvement, the process adopts high-efficiency magnetic separation equipment to achieve energy saving and consumption reduction. At present, almost all magnetic separation plants in China use a large-diameter (medium 1 050 mm, medium 1 200 mm, medium 1 500 mm, etc.) permanent magnet magnetic separator to carry out the stage tailing removing process after one stage grinding. The characteristic of permanent magnet large-diameter magnetic separator is that it can effectively separate 3~0mm or 6~0mm, or even 10-0mm coarse-grained magnetite ore, and the yield of removed tails is generally 30.00%~50.00%. The grade is below 8.00%, which creates good conditions for the magnetic separation plant to save energy and increase production.
2.Magnetic separation-fine screen process
Gangue conjoined bodies such as magnetite and quartz can be enriched when the particle size and magnetic properties reach a certain range. However, it is easy to form a coarse concatenated mixture in the iron concentrate, which reduces the grade of the iron concentrate. This kind of concentrate is sieved by a fine sieve with corresponding sieve holes, and high-quality iron concentrate can be obtained under the sieve.
There are two methods for gravity separation of hematite. One is coarse-grained gravity separation. The geological grade of the ore deposit is relatively high (about 50%), but the ore body is thinner or has more interlayers. The waste rock is mixed in during mining to dilute the ore. For this kind of ore, only crushing and no-grinding can be used so coarse-grained tailings are discarded through re-election to recover the geological grade.
The other one is fine-grain gravity separation, which mostly deals with the hematite with finer grain size and high magnetic content. After crushing, the ore is ground to separate the mineral monomers, and the fine-grained high-grade concentrate is obtained by gravity separation. However, since most of the weak magnetic iron ore concentrates with strong magnetic separation are not high in grade, and the unit processing capacity of the gravity separation process is relatively low, the combined process of strong magnetic separation and gravity separation is often used, that is, the strong magnetic separation process is used to discard a large amount of unqualified tailings, and then use the gravity separation process to further process the strong magnetic concentrate to improve the concentrate grade.
Due to the complexity, large-scale mixed iron ore and hematite ore adopt stage grinding or continuous grinding, coarse subdivision separation, gravity separation-weak magnetic separation-high gradient magnetic separation-anion reverse flotation process. The characteristics of such process are as follows:
(1) Coarse subdivision separation: For the coarse part, use gravity separation to take out most of the coarse-grained iron concentrate after a stage of grinding. The SLon type high gradient medium magnetic machine removes part of the tailings; the fine part uses the SLon type high gradient strong magnetic separator to further remove the tailings and mud to create good operating conditions for reverse flotation. Due to the superior performance of the SLon-type high-gradient magnetic separator, a higher recovery rate in the whole process is ensured, and the reverse flotation guarantees a higher fine-grained concentrate grade.
(2) A reasonable process for narrow-level selection is realized. In the process of mineral separation, the degree of separation of minerals is not only related to the characteristics of the mineral itself, but also to the specific surface area of the mineral particles. This effect is more prominent in the flotation process. Because in the flotation process, the minimum value of the force between the flotation agent and the mineral and the agent and the bubble is related to the specific surface area of the mineral, and the ratio of the agent to the mineral action area. This makes the factors double affecting the floatability of minerals easily causing minerals with a large specific surface area and relatively difficult to float and minerals with a small specific surface area and relatively easy to float have relatively consistent floatability, and sometimes the former has even better floatability. The realization of the narrow-level beneficiation process can prevent the occurrence of the above-mentioned phenomenon that easily leads to the chaos of the flotation process to a large extent, and improve the beneficiation efficiency.
(3) The combined application of high-gradient strong magnetic separation and anion reverse flotation process achieves the best combination of processes. At present, the weak magnetic iron ore beneficiation plants in China all adopt high-gradient strong magnetic separation-anion reverse flotation process in their technological process. This combination is particularly effective in the beneficiation of weak magnetic iron ore. For high-gradient strong magnetic separation, the effect of improving the grade of concentrate is not obvious. However, it is very effective to rely on high-gradient and strong magnetic separation to provide ideal raw materials for reverse flotation. At the same time, anion reverse flotation is affected by its own process characteristics and is particularly effective for the separation of fine-grained and relatively high-grade materials. The advantages of high-gradient strong magnetic separation and anion reverse flotation technology complement each other, and realize the delicate combination of the beneficiation process.
The key technology innovation of the integrated dry grinding and magnetic separation system is to "replace ball mill grinding with HPGR grinding", and the target is to reduce the cost of ball mill grinding and wet magnetic separation.
HPGRs orhigh-pressure grinding rollshave made broad advances into mining industries. The technology is now widely viewed as a primary milling alternative, and there are several large installations commissioned in recent years. After these developments, anHPGRsbased circuit configuration would often be the base case for certain ore types, such as very hard, abrasive ores.
The wear on a rolls surface is a function of the ores abrasivity. Increasing roll speed or pressure increases wear with a given material. Studs allowing the formation of an autogenous wear layer, edge blocks, and cheek plates. Development in these areas continues, with examples including profiling of stud hardness to minimize the bathtub effect (wear of the center of the rolls more rapidly than the outer areas), low-profile edge blocks for installation on worn tires, and improvements in both design and wear materials for cheek plates.
With Strip Surface, HPGRs improve observed downstream comminution efficiency. This is attributable to both increased fines generation, but also due to what appears to be weakening of the ore which many researchers attribute to micro-cracking.
As we tested , the average yield of 3mm-0 and 0.15mm-0 size fraction with Strip Surface was 78.3% and 46.2%, comparatively, the average yield of 3mm-0 and 0.3mm-0 with studs surface was 58.36% and 21.7%.
These intelligently engineered units are ideal for classifying coarser cuts ranging from 50 to 200 mesh. The feed material is dropped into the top of the classifier. It falls into a continuous feed curtain in front of the vanes, passing through low velocity air entering the side of the unit. The air flow direction is changed by the vanes from horizontal to angularly upward, resulting in separation and classification of the particulate. Coarse particles dropps directly to the product and fine particles are efficiently discharged through a valve beneath the unit. The micro fines are conveyed by air to a fabric filter for final recovery.
Air Magnetic Separation Cluster is a special equipment developed for dry magnetic separation of fine size (-3mm) and micro fine size(-0.1mm) magnetite. The air magnetic separation system can be combined according to the characteristic of magnetic minerals to achieve effective recovery of magnetite.
After rough grinding, adopt appropriate separation method, discard part of tailings and sort out part of qualified concentrate, and re-grind and re-separate the middling, is called stage grinding and stage separation process.
According to the characteristics of the raw ore, the use of stage grinding and stage separation technology is an effective measure for energy conservation in iron ore concentrators. At the coarser one-stage grinding fineness, high-efficiency beneficiation equipment is used to advance the tailings, which greatly reduces the processing volume of the second-stage grinding.
If the crystal grain size is relatively coarse, the stage grinding, stage magnetic separation-fine sieve self-circulation process is adopted. Generally, the product on the fine sieve is given to the second stage grinding and re-grinding. The process flow is relatively simple.
If the crystal grain size is too fine, the process of stage grinding, stage magnetic separation and fine sieve regrind is adopted. This process is the third stage of grinding and fine grinding after the products on the first and second stages of fine sieve are concentrated and magnetically separated. Then it is processed by magnetic separation and fine sieve, the process is relatively complicated.
At present, the operation of magnetic separation (including weak magnetic separation and strong magnetic separation) is one of the effective means of throwing tails in advance; anion reverse flotation and cation reverse flotation are one of the effective means to improve the grade of iron ore.
In particular, in the process of beneficiation, both of them basically take the selected feed minerals containing less gangue minerals as the sorting object, and both use the biggest difference in mineral selectivity, which makes the two in the whole process both play a good role in the process.
Based on the iron ore processing experience and necessary processing tests, Prominer can supply complete processing plant combined with various processing technologies, such as gravity separation, magnetic separation, flotation, etc., to improve the grade of TFe of the concentrate and get the best yield. Magnetic separation is commonly used for magnetite. Gravity separation is commonly used for hematite. Flotation is mainly used to process limonite and other kinds of iron ores
Through detailed mineralogy study and lab processing test, a most suitable processing plant parameters will be acquired. Based on those parameters Prominer can design a processing plant for mine owners and supply EPC services till the plant operating.
Prominer has been devoted to mineral processing industry for decades and specializes in mineral upgrading and deep processing. With expertise in the fields of mineral project development, mining, test study, engineering, technological processing.
gold processing cil plant in sudan | prominer (shanghai) mining technology co.,ltd
A reasonable process of the mineral processing production line achieves a higher recovery target with the lowest production cost. It should consider the sustainable supply of infrastructure, equipment, transportation, hydrology and resources in a timely manner. The three principles of the development process are: flexible transition, large processing capacity and high recovery rate. Process selection has a significant impact on gold recovery indicators.
The production process of the beneficiation production line is as follows: the mined ore is first crushed with a jaw crusher, and after crushing to a reasonable fineness, it is evenly sent to the ball mill through the elevator and the feeder, and the ore is crushed and ground by the ball mill. The ore powder ground by the ball mill enters the next process: classification. The spiral classifier cleans and classifies the ore mixture through the principle of different specific gravity of solid particles and different sedimentation rate in liquid. Due to the different specific magnetic susceptibility of various minerals, the washed and classified mineral mixture passes through the magnetic separator to separate the magnetic materials in the mixture through magnetic and mechanical forces. The mineral particles originally separated by the magnetic separator are sent to the flotation machine, and different drugs are added according to different mineral characteristics to separate the required minerals from other substances. After separating the required minerals, since they contain a large amount of water, they must first be concentrated with a thickener and then dried with a dryer to obtain dry minerals.
For some ore bodies that have already started production, the losses and economic benefits are not ideal due to improper selection of mining sites or incorrect selection of equipment or unreasonable beneficiation production lines. We can provide on-site guidance and point out the causes and deficiencies of the problem. At the same time, corresponding optimization measures and solutions are proposed to further improve the process, plan for smooth production in the future, and achieve profit or profit doubling as soon as possible.
Prominer has been devoted to mineral processing industry for decades and specializes in mineral upgrading and deep processing. With expertise in the fields of mineral project development, mining, test study, engineering, technological processing.