Green coal dressing flotation reagent as well as preparation method and application thereof

Abstract

The invention relates to the field of coal dressing flotation reagents, and discloses a green coal dressing flotation reagent and a preparation method and application thereof. The invention provides a green coal dressing flotation reagent which is composed of 70-80 parts of methyl oleate, 15-30 parts of methyl palmitate and 3-6 parts of an emulsifying agent (sorbitan oleate Span80). The preparation method comprises the following steps: firstly, weighing raw materials, magnetically stirring methyl oleate and methyl palmitate for 30 minutes, then mixing with sorbitan oleate (Span80), and heating and stirring in a water bath at 55 DEG C for 2 hours to obtain the medicament. In the application of coal slime flotation, the reagent solution is added into ore pulp and matched with a foaming agent, and flotation clean coal is formed by utilizing bubbles to carry coal slime particles. A plurality of groups of experiments show that the agent is excellent in performance, the clean coal recovery rate can reach 79.66%, the ash content is as low as 10.91%, the agent dosage is remarkably reduced compared with a traditional collecting agent, meanwhile, raw materials are green and environmentally friendly, the coal dressing industry is effectively promoted to develop towards the efficient and green direction, and the agent has extremely high application value.

Description

Technical Field

[0001] The present invention relates to the technical field of coal separation, and in particular to a green coal separation flotation agent and a preparation method and application thereof. Background Art

[0002] In the development process of the coal industry, coal preparation is of vital importance, and flotation technology, as an important means of coal preparation, plays a key role in separating coal from gangue. Flotation relies on the flotation reagent to adjust the properties of solid, liquid and gas phases in the coal slime flotation system to achieve efficient coal selection. The traditional coal preparation flotation reagent system includes collectors, frothers, flocculants, inhibitors and other auxiliary reagents. Among them, the collector plays a core role, and its performance directly affects the flotation effect.

[0003] For a long time, coal preparation plants in the coal mining industry have generally used kerosene and diesel as collectors. According to relevant statistical data, in some large coal preparation plants, when using traditional collectors, the dosage of reagents per ton of coal slime is as high as 1500-2000g, which greatly increases the cost of coal preparation and seriously compresses the profit margin of enterprises. At the same time, studies have shown that after using traditional collectors, the clean coal recovery rate of coal slime flotation can only be maintained at around 60%-70%, and a large amount of coal resources are lost during the flotation process, resulting in serious waste.

[0004] In addition, traditional collectors such as kerosene and diesel are very harmful to the environment. These agents are easy to volatilize and leak during use, and the harmful substances such as aromatic hydrocarbons contained in them will pollute the air, soil and water. For example, in soil tests around some coal preparation plants, it was found that the content of polycyclic aromatic hydrocarbons exceeded the normal standard by 5-10 times, causing long-term negative impacts on the surrounding ecological environment, and also posing a potential threat to the health of residents around the coal preparation plants.

[0005] With the continuous enhancement of environmental awareness and the increasingly stringent environmental regulations, the coal preparation industry urgently needs to seek a new flotation agent that can not only meet the needs of efficient flotation but also meet green environmental protection standards, so as to break through the current technical bottleneck and realize the sustainable development and utilization of coal resources. Summary of the invention

[0006] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a green coal flotation reagent, which is composed of the following substances in percentage by mass: 70-80 parts of methyl oleate, 15-30 parts of methyl palmitate, and 3-6 parts of an emulsifier, wherein the emulsifier is sorbitan oleate.

[0007] A method for preparing a green coal flotation agent comprises the following steps: Step 1: weigh 70-80 parts of methyl oleate, 15-30 parts of methyl palmitate, and 3-6 parts of emulsifier; Step 2: Under magnetic stirring, add the methyl oleate and methyl palmitate weighed in step 1 into the reaction container according to the proportion, and stir for 30 minutes; Step 3: Mix the solution obtained in step 2 and sorbitan oleate (Span80), and stir for 2 hours under the condition of heating in a water bath at 55° C. to obtain the green coal flotation agent.

[0008] A method for applying a green coal flotation agent in coal preparation, during coal slime flotation, the novel flotation agent solution is added to the ore pulp, a frother is continuously added to form a stable foam layer, and the air bubbles are used to carry the coal slime particles to the foam layer, which are scraped out as flotation clean coal.

[0009] Preferably, the methyl oleate has good capture performance for coal slime and can effectively increase the yield of clean coal.

[0010] Preferably, the methyl palmitate has good selectivity in coal slime flotation and can effectively reduce the ash content of clean coal during the flotation process.

[0011] Preferably, sorbitan oleate as an emulsifier can make the oil droplet diameter of the oil collector in the slurry smaller, increase the adsorption area and probability on the surface of coal particles, thereby improving the flotation effect, reducing the dosage of reagents, and reducing costs.

[0012] Compared with the existing technology, the beneficial effects of the present invention are: excellent agent performance: methyl oleate has a strong affinity with coal slime, and captures coal particles by chemical bonding (such as van der Waals force and hydrophobic effect), and the clean coal yield can be greatly improved. Methyl palmitate selectively adsorbs specific groups of coal particles (such as hydroxyl and carboxyl). Here, hydroxyl and carboxyl are hydrophilic groups, and the collector does not adsorb with them. The selectivity of the collector is mainly manifested in the difference in the adsorption capacity of the collector to carbon ash. Good selectivity indicates better adsorption capacity for carbon in flotation, which can effectively reduce ash content. Sorbitan oleate makes the oil droplet diameter of the oil collector in the ore pulp smaller, increases the adsorption area and probability with the surface of the coal particles, reduces the amount of reagents used, reduces costs and improves efficiency.

[0013] The environmental advantages are significant: the raw materials are non-toxic and harmless, with good biodegradability, and no harmful emissions during the preparation and use process. It complies with environmental protection regulations, ensures environmental friendliness from the source and process, and empowers the sustainable development of the coal preparation industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a table of relevant data and effects corresponding to each embodiment of a green coal flotation agent proposed by the present invention. DETAILED DESCRIPTION

[0015] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0016] Referring to the figure, this embodiment provides a green coal flotation reagent, which is composed of the following substances in percentage by mass: 70-80 parts of methyl oleate, 15-30 parts of methyl palmitate, and 3-6 parts of an emulsifier, wherein the emulsifier is sorbitan oleate.

[0017] The above raw materials selection principle: Methyl oleate (70-80 parts): It is the key collecting component of the flotation agent. In the process of coal slime flotation, methyl oleate has good collecting performance for coal slime due to its special chemical structure and properties. Its molecules can interact with the surface of coal particles, making coal particles that are not easy to float become easy to attach to bubbles, thereby effectively improving the yield of clean coal. For example, in actual coal preparation operations, methyl oleate can enhance the hydrophobicity of coal particles by attracting each other with the hydrophobic areas on the surface of coal particles, making them easier to be carried to the foam layer by bubbles, thereby increasing the recovery of clean coal.

[0018] Methyl palmitate (15-30 parts): In the flotation system, methyl palmitate mainly plays the role of enhancing selectivity. Specifically, methyl palmitate selectively adsorbs specific groups of coal particles (such as hydroxyl and carboxyl). In addition, hydroxyl and carboxyl are hydrophilic groups, and the collector does not adsorb them. The selectivity of the collector is mainly reflected in the difference in the adsorption capacity of the collector to carbon and ash. Good selectivity indicates better adsorption capacity for carbon in flotation, which can effectively reduce ash content. Therefore, it can help distinguish impurities such as coal and gangue during coal slime flotation, and effectively reduce the ash content of clean coal during flotation.

[0019] Emulsifier Sorbitan oleate (Span80) (3-6 parts): As an emulsifier, Span80 plays a vital role in the entire flotation reagent system. It can reduce the interfacial tension between methyl oleate and methyl palmitate and the water phase, so that the reagents are better dispersed in the slurry and the effect of the reagents is improved. Specifically, sorbitan oleate makes the oil droplet diameter of the oil collector in the slurry smaller, increases the adsorption area and probability on the surface of the coal particles, and in practical applications, this helps to reduce the amount of reagents used and reduce the cost of coal preparation, because under the same flotation effect, since Span80 improves the utilization efficiency of the reagents, less reagents can be used to achieve the desired flotation target.

[0020] A method for preparing a green coal flotation agent comprises the following steps: Step 1: Weigh 70-80 parts of methyl oleate, 15-30 parts of methyl palmitate, and 3-6 parts of emulsifier; this step is to use an electronic scale with an accuracy of 0.1 grams, and weigh the specified amount of raw materials at a temperature of 20-25°C and a relative humidity of 40%-60%.

[0021] Step 2: Under magnetic stirring conditions, the methyl oleate and methyl palmitate weighed in step 1 are added to a reaction container in proportion and stirred for 30 minutes; in the specific implementation here, methyl oleate and methyl palmitate are placed in a glass reaction container with a volume of 500-1000 ml, and stirred at 200-300 rpm for 30 minutes in a magnetic stirring device (magnetic field strength 50-100 Gauss).

[0022] Step 3: Mix the solution obtained in step 2 with sorbitan oleate (Span80), and stir for 2 hours under the condition of heating in a water bath at 55°C to obtain the green coal flotation agent; Here, step 3 is to mix the solution obtained in step 2 with sorbitan oleate (Span80), place it in a 55°C water bath heating device with a temperature control accuracy of ±1°C, and stir at 100-150 rpm for 2 hours. The entire preparation process is completed in a well-ventilated room that meets national laboratory safety standards.

[0023] A method for applying a green coal flotation agent in coal preparation, during coal slime flotation, the novel flotation agent solution is added to the ore pulp, a frother is continuously added to form a stable foam layer, and the air bubbles are used to carry the coal slime particles to the foam layer, which are scraped out as flotation clean coal.

[0024] Furthermore, when the coal flotation agent is used in coal preparation, 700-900 grams of the flotation agent solution can be added to the slurry per ton of coal slime, and then a frother is added (the addition amount is 50-100 ml / ton of coal slime), the impeller speed of the flotation machine is maintained at 1500-2000 rpm, and the aeration volume is maintained at 0.5-1.0 cubic meters / hour / square meter.

[0025] In practical applications, the methyl oleate has good capture performance for coal slime and can effectively improve the yield of clean coal.

[0026] In practical applications, the methyl palmitate has good selectivity in coal slime flotation and can effectively reduce the ash content of clean coal during the flotation process.

[0027] In practical applications, sorbitan oleate as an emulsifier can make the oil droplet diameter of the oil collector in the slurry smaller, increase the adsorption area and probability on the surface of coal particles, thereby improving the flotation effect, reducing the dosage of reagents and reducing costs.

[0028] According to the technical contents mentioned in the above embodiments, the applicant has also made the following extended implementation cases to verify the effect: 1. A green coal flotation agent, the raw materials for its preparation are composed of the following components in parts by weight: 72 parts of methyl oleate, 24 parts of methyl palmitate, and 4 parts of emulsifier.

[0029] Follow the steps below to implement: Step 1. Weigh 72 parts of methyl oleate, 24 parts of methyl palmitate, and 4 parts of emulsifier; Step 2. Under magnetic stirring, add the methyl oleate and methyl palmitate weighed in step 1 into the reaction vessel in proportion and stir for 30 minutes; Step 3: Mix the solution obtained in step 2 and sorbitan oleate (Span80), and stir for 2 hours under the condition of heating in a water bath at 55°C to obtain the novel coal flotation agent.

[0030] A fat coal sample is selected as a flotation coal sample, and the flotation performance of the mineral processing agent of this embodiment is measured according to "GB / T4757-2001 "Coal Powder (Mud) Laboratory Unit Flotation Test Method". Specifically as follows: accurately weigh 120g of the coal sample to be selected, add water to the flotation tank to the second mark, start and debug the flotation machine to make the impeller speed reach the specified value at most, stop the machine, close the air inlet valve, and drain the water in the flotation tank; add water to the flotation tank to the first mark, start the flotation machine, add 120g of coal sample to the tank, stir until the coal sample is completely wetted, and then add water to make the coal slurry level reach the second mark; after stirring for 2 minutes, add the new environmentally friendly mineral processing agent of this embodiment below the coal slurry surface, stir for 10 seconds, open the air inlet valve, and start scraping bubbles at the same time. The full tank width should be collected as the foam thickness changes. The concentrate foams into a special container, and the water replenishment speed is controlled to keep the slurry level constant during the entire scraping period. At the end of the scraping, the particles on the flotation tank wall should be washed into the slurry with a washing bottle; after scraping for 3 minutes, stop scraping, close the air intake valve and the stirring motor, put the tail coal into a special container, and the particles deposited in the lower part of the flotation tank should be washed into the tail coal container. The particles stuck to the scraper and the lip and wall of the flotation tank should be collected into the clean coal product. Add clean water to the flotation tank, and start the flotation machine to stir and clean until the flotation tank is clean; finally, filter, dry, weigh and test the ash content of the foam product and the slurry. Measure the clean coal recovery rate and ash content.

[0031] The amount of mineral processing reagent used in this embodiment is 800g / t, the clean coal recovery rate is 78.98%, and the ash content is 11.53%.

[0032] 2. The difference from Example 1 is that a new environmentally friendly mineral processing agent is composed of the following substances in parts by weight: 70 parts of methyl oleate, 25 parts of methyl palmitate, and 5 parts of emulsifier. The amount of the mineral processing agent in this example is 800g / t, the clean coal recovery rate is 79.74%, and the ash content is 11.21%.

[0033] 3. The difference from the extended implementation mode 1 is that a new environmentally friendly mineral processing agent is composed of the following substances in parts by weight: 79 parts of methyl oleate, 15 parts of methyl palmitate, and 6 parts of emulsifier. The dosage of the mineral processing agent in this embodiment is 800g / t, the clean coal recovery rate is 80.17%, and the ash content is 11.45%.

[0034] 4. The difference from the extended implementation mode 1 is that a new environmentally friendly mineral processing agent is composed of the following substances in parts by weight: 75 parts of methyl oleate, 21 parts of methyl palmitate, and 4 parts of emulsifier. The amount of the mineral processing agent in this embodiment is 800g / t, the clean coal recovery rate is 79.66%, and the ash content is 10.91%.

[0035] 5. The difference from the extended implementation mode 1 is that a new environmentally friendly mineral processing agent is composed of the following substances in parts by weight: 77 parts of methyl oleate, 18 parts of methyl palmitate, and 5 parts of emulsifier. The amount of mineral processing agent used in this embodiment is 800g / t, the clean coal recovery rate is 79.75%, and the ash content is 11.59%.

[0036] In the above extended implementation modes 1-5, during the experiment, methyl oleate, methyl palmitate, sorbitan oleate (Span80) are all non-toxic, environmentally friendly green agents. Methyl oleate has good collection performance for coal slime and can effectively improve the yield of clean coal; methyl palmitate has good selectivity in coal slime flotation. Specifically, methyl palmitate selectively adsorbs specific groups of coal particles (such as hydroxyl and carboxyl). Hydroxyl and carboxyl are hydrophilic groups, and the collector does not adsorb with them. The selectivity of the collector is mainly manifested in the difference in the adsorption capacity of the collector to carbon ash. Good selectivity indicates better adsorption capacity for carbon in flotation, which can effectively reduce the ash content and can effectively reduce the ash content of clean coal during flotation; sorbitan oleate (Span80) is an emulsifier, which makes the oil droplet diameter of the oil collector in the ore pulp smaller, increases the adsorption area and probability with the surface of the coal particles, thereby improving the flotation effect, reducing the dosage of the reagent, and reducing the cost. It can be observed that the mineral processing agent of Example 4 has strong continuous foaming ability, stable foam, strong collecting ability, good selectivity, clean coal recovery rate of 79.66%, ash content of 10.91%, and the best effect.

[0037] The above specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

[0038] In addition, in the description of the present invention, it should be understood that the terms indicating orientation or positional relationships are based on the orientation or positional relationships shown in the drawings and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0039] Furthermore, in the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

Claims

1. A green coal flotation reagent, characterized in that: The invention is composed of the following substances in percentage by mass: 70-80 parts of methyl oleate, 15-30 parts of methyl palmitate and 3-6 parts of an emulsifier, wherein the emulsifier is sorbitan oleate (Span80).

2. A method for preparing the green coal flotation agent according to claim 1, characterized in that: The following steps are involved: Step 1: weigh 70-80 parts of methyl oleate, 15-30 parts of methyl palmitate, and 3-6 parts of emulsifier; Step 2: Under magnetic stirring, add the methyl oleate and methyl palmitate weighed in step 1 into the reaction container according to the proportion, and stir for 30 minutes; Step 3: Mix the solution obtained in step 2 and sorbitan oleate (Span80), and stir for 2 hours under the condition of heating in a water bath at 55° C. to obtain the green coal flotation agent.

3. The method for applying the green coal flotation agent in coal preparation according to claim 1, characterized in that: During coal slime flotation, the novel flotation agent solution of claim 1 is added to the ore pulp, and a frother is continuously added to form a stable foam layer. The coal slime particles are carried to the foam layer by air bubbles and scraped out as flotation clean coal.

4. The green coal flotation reagent according to claim 1, characterized in that: The methyl oleate has good capture performance for coal slime and can effectively improve the yield of clean coal.

5. The green coal flotation reagent according to claim 1, characterized in that: The palmitic acid methyl ester has good selectivity in coal slime flotation and can effectively reduce the ash content of clean coal during the flotation process.

6. The green coal flotation reagent according to claim 1, characterized in that: Sorbitan oleate (Span80) as an emulsifier can make the oil droplet diameter of the oil collector in the slurry smaller, increase the adsorption area and probability on the surface of coal particles, thereby improving the flotation effect, reducing the dosage of reagents and reducing costs.

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