The issue of how to use flotation reagents correctly is the issue of how to correctly determine the medicament system before flotation. The medicament system refers to the type of reagents added during the flotation process, the amount of reagents, the method of addition, the location of dosing, the order of dosing, etc. The reagent system of the flotation plant is related to the nature of the ore, the process flow, the several mineral processing products that need to be obtained, and other factors. related. It is usually determined through optional testing of ores or semi-industrial testing. The pharmaceutical system is an important factor affecting the technical and economic indicators of mineral processing.
1. Types of chemicals The types of chemicals used in a flotation plant are related to factors such as the nature of the ore, the process flow, and the types of mineral processing products that need to be obtained. It is usually determined through optional testing of ores or semi-industrial testing. The types of pharmaceuticals are divided according to their functions and can be roughly divided into three categories. ● Foaming agent: organic surface-active substances distributed on the water-air interface. Used to produce a foam layer that can float minerals. Foaming agents include pine oil, cresol oil, alcohols, etc.; ● Collecting agent: Its function is to collect the target mineral. The collecting agent can change the hydrophobicity of the mineral surface. Make the floating mineral particles adhere to the bubbles. According to the action properties of the agent, it is divided into non-polar collectors, anionic collectors and cationic collectors. Commonly used collectors include black medicine, xanthate, white medicine, fatty acids, fatty amines, mineral oil, etc.; ● Adjusters: Adjusters include activators and inhibitors, which change the properties of the surface of mineral particles and affect the minerals and collectors. Adjusters are also used to change the chemical or electrochemical properties of aqueous media, for example, changing the pH value and the state of the collector in it. Adjusters include: ①. pH adjuster: lime, sodium carbonate, sulfuric acid, sulfur dioxide; ②. Activator: copper sulfate, sodium sulfide; ③. Inhibitor: lime, yellow blood salt, sodium sulfide,
Sulfur dioxide, sodium cyanide, zinc sulfate, potassium dichromate, water glass, tannin, soluble colloid, starch, synthetic polymers, etc.; ④. Others: wetting agents, floating agents, solubilizers, etc.
2. Dosage of reagents: The dosage of reagents should be just right during flotation. Insufficient or excessive dosage will affect the mineral processing index, and excessive dosage will increase the cost of mineral processing. The relationship between the dosage of various chemicals and flotation indicators is: ①. Insufficient dosage of collector and insufficient hydrophobicity of minerals will reduce the recovery rate. Excessive dosage will reduce the quality of the concentrate and bring difficulties to separation and flotation; ②. Insufficient dosage of foaming agent will lead to poor foam stability. If the dosage is too large, “groove running” will occur; ③. If the dosage of activator is too small, the activation will not be good. If the dosage is too large, the selectivity of the flotation process will be destroyed; ④. Insufficient dosage of inhibitors will result in low concentrate grade. Excessive dosage will inhibit the minerals that should emerge and reduce the recovery rate.
3. Pharmacy configuration dilutes solid pharmaceuticals into liquids for easy addition. Agents with poor water solubility, such as xanthate, amylanine, sodium silicate, sodium carbonate, copper sulfate, sodium sulfide, etc., are all prepared into aqueous solutions and added in concentrations ranging from 2% to 10%. Agents that are insoluble in water should be dissolved in a solvent first, and then added into an aqueous solution, such as amine collectors. Some can be added directly, such as #2 oil, #31 black powder, oleic acid, etc. For pharmaceuticals that are easily soluble in water and have a large dosage, the preparation concentration is generally 10 to 20%. For example, sodium sulfide is prepared at 15% when used. For pharmaceuticals that are poorly soluble in water, organic solvents can be used to dissolve them and then be prepared into low-concentration solutions. The choice of pharmaceutical preparation method is mainly based on the properties, addition methods and functions of the pharmaceutical. The same medicine has great differences in dosage and effect due to different preparation methods. Generally, the preparation methods are: 1. Prepared into a 2% to 10% aqueous solution. Most water-soluble medicines are prepared in this way (such as yellow medicine, copper sulfate, sodium silicate, etc.); ②. Prepare with solvents. Some water-insoluble medicines can be dissolved in special solvents. For example, Baiyao is insoluble in water, but soluble in 10% to 20% Aniline solution can only be used after it is prepared into a mixed solution of aniline; another example is that aniline black drug is insoluble in water, but can be dissolved in an alkaline solution of sodium hydroxide, so when using aniline black drug, you must first prepare sodium hydroxide. Alkaline solution, and then add the agent to prepare a aniline black solution and add it to the flotation agent; ③. Prepare it into a suspension or emulsion. For some solid agents that are not easily soluble, it can be prepared into an emulsion. If the solubility of lime in water is very small, the lime can be ground into powder and mixed with water to form a milky suspension (such as lime milk), or it can be added directly to the ball mill and stirring barrel in the form of dry powder; ④. Saponification, for fatty acid capture As collector, saponification is the most common method. For example, when selecting hematite, oxidized paraffin soap and Tarr oil are used together as collector. In order to saponify tar oil, when preparing pharmaceuticals, add about 10% sodium carbonate and heat it to make a hot soap solution; ⑤. Emulsification. The emulsification method is to use ultrasonic emulsification, or use mechanical strong stirring to emulsify. For example, after emulsification of fatty acids and diesel oil, their dispersion in the slurry can be increased and the effect of the agent can be improved. Adding some emulsifiers will have better effects. Many surface-activated substances can be used as emulsifiers; ⑥. Acidification. When using a cation collector, due to its poor solubility, it must be pre-treated with hydrochloric acid or acetic acid before it can be dissolved in water and used for flotation. ; ⑦. The aerosol method is a new preparation method that enhances the effect of pharmaceuticals. Its essence is to use a special spray device to atomize the pharmaceuticals in the air medium and add them directly to the flotation tank. within, so it is also called “aerosol flotation method”. Using this method not only improves the floatability of useful minerals, but also significantly reduces the dosage of chemicals. For example, the collector is only 1/3 to 1/4 of the usual dosage, and the frother dosage is only 1/5; ⑧. Electrochemical treatment of reagents. In the solution, direct current is applied to chemically treat the flotation reagents. It can change the state of the agent itself, the pH value of the solution and the redox potential value, thereby achieving the purpose of increasing the concentration of the most activating agent component, increasing the critical concentration for forming colloidal particles, and improving the dispersion of poorly soluble agents in water. . Usually collectors and foaming agents can be stirred for 1-2 minutes, but some agents require long-term stirring, such as potassium dichromate for copper-lead separation to inhibit lead.
4. Dosing location In order to give full play to the effect of flotation reagents, the general approach to dosing location is: regulators, inhibitors and some collectors (such as kerosene) are added to the ball mill to create a suitable flotation environment as soon as possible. . The collector and frother are added in the first stirring tank of flotation. If the flotation operation has two mixing barrels, the activator should be added to the first mixing barrel, and the collector and frother should be added to the second mixing barrel. Depending on the role of the agent in the flotation machine, the adding location is also different. For example, there are three chemicals: copper sulfate, xanthate, and pine alcohol oil. The general dosing sequence is to add copper sulfate to the center of the first stirring tank, xanthate to the center of the second stirring tank, and pine alcohol oil to the center of the second stirring tank. Exit. Under normal circumstances, flotation plants first add a pH adjuster to adjust the slurry to a suitable pH value in order to better exert the effects of collectors and inhibitors. When adding chemicals, be aware that some harmful ions may cause the medication to fail. For example, the reaction between copper ions and hydride ions will cause the hydride to fail. During copper-sulfur separation, if more copper ions appear in the stirring tank, do not add cyanide to the stirring tank, but add it directly to the separation float. Selecting work.
5. Dosing sequence The general dosing sequence of a flotation plant is: for the flotation of raw ore, it should be: pH adjuster, inhibitor or activator, frother, collector; flotation of minerals that have been inhibited For: activator, collector, foaming agent.
6. There are usually two methods of dosing: centralized addition and dispersed addition. The general principle is: for agents that are easily soluble in water, difficult to be taken away by foam, and difficult to expire, they can be added together, that is, all agents can be added at once before rough selection. On the contrary, those agents that are easily carried away by the foam and are easily rendered ineffective by interacting with fine mud and soluble salts should be added in stages. Adjusters, inhibitors and some collectors (such as kerosene) are added to the ball mill, and collectors and foaming agents are mostly added to the first mixing barrel of flotation. If there are two mixing barrels in the flotation operation, they should be added in the third mixing barrel. Add activator to one mixing barrel, and add collector and foaming agent to the second mixing barrel (such as zinc flotation operation).
Post time: Aug-28-2024
