First, the depth of pulp
Refers to the depth of the pulp slurry of solid minerals and liquid (water) or weight-based, conventional solid or liquid-solid ratio concentrator depth representation, selected from the plant, said solid coal, flotation common depth as follows:
*The concentration is the concentration when the slime is concentrated and flotation
The flotation depth of the ore dressing is closely related to the overflow depth of the classifier. Generally, the roughing depth is consistent with the overflow depth of the classifier, and the overflow depth is required for the grinding.
The fineness is related. If the abrasive grain is required to be fine, the overflow will be thin; otherwise, the overflow will be thick. The concentration of sweeping is always thinner than coarse selection. When the flotation material has a fine particle size, the concentration should be relatively thin. The effect of slurry concentration on flotation is mainly reflected in the aeration of the slurry, the concentration of the agent in the slurry, and the production volume.
1. The effect on the amount of inflation
The amount of aeration of the flotation machine varies with the concentration of the slurry, and the excessively concentrated and too lean pulp causes the aeration to deteriorate.
2. Drug concentration
Under the condition of a certain amount of dosing, when the concentration of the slurry is large, the concentration of the agent is also large. Therefore, the concentration of the slurry can be used to appropriately reduce the dosage, while in the case of low concentration, the dosage should be appropriately increased. Therefore, the concentration is high. When you choose, you can save money.
3. Production
If the concentration of the slurry increases, if the volume and productivity of the flotation machine remain unchanged, the residence time of the slurry in the flotation machine can be relatively extended, which is beneficial to increase the recovery rate. On the contrary, if the flotation time is constant, the concentration of the slurry is increased. It can increase the productivity of the flotation machine.
Generally, the concentration of the slurry is relatively thin, and the recovery rate is low, but the quality of the concentrate is good. Therefore, the coarse selection of the slurry is used, and the concentration of the slurry is selected. The concentration of the sweep is generally determined by the coarse selection concentration. In addition, when the material has a coarse particle size and a large particle size, a relatively thick pulp is often used: conversely, a relatively thin pulp can be used.
Second, the pH of the pulp
The pH value of the slurry is one of the important factors controlling the flotation process. It affects both the surface properties of the mineral and the effects of various flotation agents.
1. Influence on the surface properties of minerals
The pH value has a great influence on the electrical properties of the mineral surface. It is recalled that when PH> mineral zero point, the mineral surface is negatively charged; when PH<zero point, the mineral surface is positively charged, the electrical surface of the mineral on the fine mud covers it and the physical of the agent Adsorption has an extremely important role.
2. The efficacy of the agent and its effect on the mineral surface
Most of the collectors used in the flotation are ionic. The dissociation committee of the agent directly affects the flotation effect, and the PH value is closely related to the degree of dissociation. In order to improve the effect of the agent, the pH value of the pulp should be related to the agent. The range of pH values ​​that produce more ions is consistent. For example, multi-alkaline medium in the case when the amine oxide ore by flotation nonferrous metals. Some medicines are easily decomposed and deactivated at a certain pH value, such as xanthate, dissociated in water to form xanthate, xanthate is hydrolyzed to produce xanthogen, xanthogen is weak acid, in acidic medium Easy to decompose, the lower the PH value, the faster the decomposition, resulting in the failure of xanthate.
In the contact curve, the PGH value of the pulp can be adjusted to inhibit or smoothly perform flotation at a certain concentration of the agent. Therefore, in order to make the drug fully effective, the action of the agent and the mineral surface is controlled to smoothly carry out the flotation process, and the pH value of the slurry is appropriately adjusted during flotation. When sorting various ores, the time range is shifted to the appropriate pH range. According to the experience of long-term production practice, the PH value of common sulfide ore flotation is shown in the following table:
Third, the temperature of the flotation slurry
The flotation process is similar to many physical and chemical processes. The temperature rise will undoubtedly speed up the flotation process and improve the flotation index. However, most flotation plants currently perform flotation at room temperature. Heating flotation is only available when certain agents must be at a certain temperature to be effective, or if some processes have special requirements.
1. Effect of slurry temperature on dosage and effect of medicament
Part of the use of fatty acid trapping agent oxidizing ore flotation plant, often the pulp is heated to 30-35 ° C or so for sorting. This can improve the dispersion and utility of the fatty acid collector, reduce the amount of flotation agent, and clearly float the technical indicators.
For example, when flotation fluorite , the test using rouge as a collector shows that: increasing the temperature of the pulp, under the same amount of collected Liu, can make the sorting index significantly improved; if you want to get the same index, the pulp When the temperature is increased, the amount of the collector can be greatly reduced. The slurry temperature is in the range of 10-30 degrees, and the amount of rouge is related to the mine temperature: Y=640-13x type Y---Rouge dosage, g/t;
x---Pulp temperature, °C. It can be seen from the above formula that with the increase of temperature, the amount of fat is reduced, and under the same beneficiation index, when the slurry temperature is 30 °C, the amount of rouge is only 10 Half of °C.
Temperature has a greater effect on saturated fatty acids. For example, oxidized paraffin ore is a saturated fatty acid-based soap salt. When the temperature is lower than 40 °C, its collection performance is not as good as that of oleic acid, but when the temperature is close to 70 °C, it is collected. Performance is better than oleic acid. Even if used in combination with other chemicals, the pulp needs to be heated to 30-40 ° C, and oxidized paraffin soap can better capture performance.
2. Desorb the adsorbed film of the adsorbent
The surface of the sulfide mineral that has been adsorbed to xanthate, added lime, heated and stirred, can remove the mineral collector film, and then add inhibitor to achieve the separation of polymetallic ore. For example, the copper- molybdenum mixed concentrate selected by the xanthate collector is separated, and in the high alkalinity pulp caused by the lime, the copper-molybdenum mixed concentrate is heated by steam to make the surface of the sulfide such as copper sulfide and iron sulfide. Desorbing or destroying the collector film, the surface of the sulfide ore outside the molybdenum ore is oxidized and inhibited, and the surface of the molybdenite is not easily oxidized. Therefore, after the heating treatment, the refining and foaming agent are added to float the money mine. .
The process may also be separated in copper zinc, copper floating suppressing zinc; zinc when separating sulfur, has good floatability good inhibition of pyrite concentrate mixed copper sulfur separation, can effectively inhibit The pyrite with good floatability improves the separation efficiency of copper and sulfur. It is also possible to add sodium sulfide and then add steam to heat, or add sulfur dioxide and then add gas to heat to separate the mixed concentrate. When the copper-molybdenum mixed concentrate is separated, the slurry heating can reduce the amount of sodium sulfide; the separation of zinc and sulfur plus sulfur dioxide and steam heating can cause acidic medium, have a cleaning and activation effect on pyrite, and warm to promote the decomposition of xanthate. Desorption promotes the inhibition of sphalerite by sulfur dioxide. This method has been used to float pyrite from zinc concentrates to improve the quality of zinc concentrates. This method uses a reducing agent such as sulfur dioxide to enhance the inhibition of the ore by heating the strengthening agent.
The slurry is heated separately. According to the degree of desorption of various mineral surface collector films, the minerals can be separated. For example, when the zinc-sulfur mixed concentrate is separated, this method is applied without any agent to make the pyrrhotite and yellow. The iron ore is suppressed and the sphalerite can be floated out. When the slurry is warmed, the floatability of the fine-grained minerals can be removed, the de-sludge effect can be eliminated, the mixing and flotation time can be coordinated, and the pollution of the tailings caused by the overdose can be reduced.
Fourth, water quality
Flotation is carried out in an aqueous medium containing various gases, ions, and some organic flotation agents, all of which can affect the flotation process. The composition of water in different regions varies greatly. Therefore, it is necessary to have sufficient water quality and the flotation process can be properly adjusted.
1. Water quality standards
Industrial water and life have hard water, soft water, water hardness reaction water calcium, magnesium ion content, the greater the hardness of water, the more calcium and magnesium ions contained.
The calculation criteria for hardness in different countries are different, such as German hardness, American hardness, French hardness, British hardness, etc., and the use of milliequivalent hardness, 1 meq equivalent of hardness equivalent to 20 mg of calcium ion in 1 L of water, or 12.16 mg of magnesium ion. After the change, 1 milligram equivalent hardness = 2.804 German hardness = 50.045 American hardness = 5 French hardness. The soft stem grade of water is shown in the table below:
The effect of water hardness on the flotation index is obvious. Especially when using fatty acid collectors for flotation, the effects must be eliminated before flotation.
The problem of various ions, molecules and compounds contained in water is called the total mineralization of water, also known as the degree of mineralization, expressed as [g/L]. The degree of mineralization indicates the degree of mineralization of water, that is, the amount of salt in the water. The higher the degree of mineralization of water, the higher the salt content in the water and the more polyvalent metal ions. Some of these ions are beneficial to flotation, some are harmful; they have different effects on different minerals. Therefore, the components used in flotation should be fully understood to facilitate the adjustment of the flotation process and improve the flotation effect.
2. Rivers, lakes and water
The water of rivers and lakes is one of the most used waters in the flotation. Most of them are soft water, and the degree of mineralization is low. Except for the Great Salt Lake, such as Lauren Lake is only 0.3048g/L, Baikal Lake is 0.069g/L. Naxi Lake 0.1511g / L. The salt content is low, and the polyvalent metal ion is relatively small. In the flotation, the water factor has the least influence on the sorting effect, and is easy to perform and adjust.
3. Groundwater
Groundwater is also one of the most used waters in the flotation. The water in different areas has a large variation in water quality, and the hardness and salinity are very different. The soft water with low salinity and low hardness, like the water in rivers and lakes, has little influence on flotation, and is easy to operate and control in the flotation.
As the degree of mineralization increases, the hardness increases, the content of various ions in the water increases, and the effect on the flotation effect is also significantly increased. The hardness of the water is various metal ions, and the effect of fatty acid traps is particularly large. Magnesium plasma not only increases the consumption of collectors, but also often destroys the selectivity of the flotation process. For example, in the flotation of iron ore, calcium ions activate quartz and silicate gangue; iron ions inhibit the flotation of sulfide minerals; copper ions can activate, and alkali metals generally affect flotation. Not big.
Since the ions in the water have an obvious influence on the flotation index, the harmful effects must be eliminated before the flotation. There are chemical and physical methods for elimination. Chemical methods can be used by adding certain chemicals to form insoluble precipitates of harmful metals, such as sodium carbonate and anti-bottled sodium. The Donganshan plant has added 1.5-2.0kg/t sodium carbonate to the grinding back, so that the hardness of the water is reduced from 12 German degrees to 7-8 degrees. It can also be ion exchanged. This adaptability is strong. According to your needs, choose different types of exchange resin for the required purpose.
The physical method can achieve the purpose of eliminating harmful ions by using ultrasonic waves and electromagnetic treatment.
4. Salt water
Seawater and some lake waters have higher salinity, so the salinity is also higher. For example, the Ai Pai Kuon Lagoon (seawater) is 375.1g/L, which belongs to salt water. The use of salt water for flotation is of great significance to coastal mines or the salt lake area. Some minerals have been subjected to flotation tests in salt water, and their effects are different. For example, a coal mine water contains Na+1789.6mg/L, Cl-2141.3mg/L, Mg2+28.4mg/L, SO42- 131.6mg/L, used for flotation of coal slime, can get very lone index without adding flotation agent, and the flotation speed is 60% higher than ordinary fresh water.
To be a lead-zinc flotation with sea water to a certain extent, increase the amount of lime, copper sulfate and other agents, but also improves the floating gangue in flotation gangue need to add water glass to suppress. The grade and recovery rate of zinc concentrate is slightly lower than that of fresh water. Because of the high salt content, salt water has a certain corrosive effect on equipment, so it is necessary to pay attention to protection.
5. Backwater
After the return water is treated by the tailings of the concentrator, it is returned to the reused water, which is called circulating water in the coal preparation plant. Due to the serious shortage of water resources springs and the requirements of environmental protection, the wastewater of well-ordered plants needs to be returned to use, and it has received more and more attention. There are two characteristics of flotation backwater:
(1) Containing more flotation reagents, the composition is more complicated, and the reagents in the return water are sometimes 50-100 times higher than the new water. They must be considered for their influence on the flotation process. If used improperly, the sorting may be affected. The effect; when used properly, can save the medicine. Practice has proved that when flotation of single metal ore, the types of chemicals are small and the impact is single, so the use of return water is relatively simple, and all the return water can be used. For example, in the case of copper- nickel- sulfur flotation, in water, 23% of the collector xanthate is reduced, and the amount of sodium hydroxide is reduced by 17%.
When selecting polymetallic ore, the use of various types of chemicals, inhibition, activation and other interactions, the recycling of recycled water, the use of mixed flotation, mixed concentrate and separation process, can make the use of return water is relatively simple. For example, lead-zinc mixed flotation, mixed concentrate streams and mineral water can be returned to the front of the process. When the situation is more complicated, in principle, it is more appropriate to return the wastewater discharged from the same circuit to the same circuit, but the pipeline and the process are more complicated. Under this kind of sentiment, the recycling scheme and proportion of the return water should be determined through experiments.
(2) Containing more solid materials, especially fine mud, solid matter in the return water, fine particle size, low grade or high ash content, easy to cover the surface of coarse particles after recycling, severely correct flotation effect, Generally, the mineral content in the water should not exceed 0.2-0.3g/L. Eliminate solid matter in the backwater and reduce it by natural clarification or by adding a coagulant. The coagulant is lime, lime and ferrous sulfate or aluminum sulfate. In order to eliminate calcium ions, aluminum sulfate can also be used as a coagulant alone. The tail coal water treatment of the coal preparation plant often adds polyacrylamide to flocculate the solid particles.
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