Method for preparing silicon-potassium fertilizer from graphite tailings

Abstract

The invention relates to a method for preparing a silicon-potassium fertilizer from graphite tailings. The method comprises the following steps: grinding the graphite tailings; adding an auxiliary agent after grinding, and stirring while boiling; performing microwave treatment after stirring; after microwave treatment, adding the kitchen garbage and grinding again; and grinding the product to obtain a silicon-potassium fertilizer product. According to the method for preparing the silicon-potassium fertilizer by utilizing the graphite tailings, the silicon-potassium fertilizer is prepared by taking the graphite tailings as a raw material, the content of silicon and potassium in the graphite tailings is relatively high, and silicon dioxide and potassium oxide in the graphite tailings can provide silicon and potassium elements and serve as raw materials for preparing the silicon-potassium fertilizer; a large amount of graphite tailings can be consumed to prepare the silicon-potassium fertilizer, the manufacturing cost is reduced, air and environment pollution is reduced, and remarkable social and economic benefits are achieved.

Description

Technical Field

[0001] The invention relates to a solid waste treatment method, and in particular to a method for preparing silicon-potassium fertilizer by utilizing graphite tailings. Background Art

[0002] Nitrogen, phosphorus and potassium are the three major fertilizers that are indispensable nutrients in the growth of crops. Their stable prices and guaranteed supply are also important components of food security and agricultural security.

[0003] Nitrogen fertilizer has a mature production process and its raw materials are only coal (or natural gas) and air. Therefore, it has developed rapidly in a coal-producing country like China, and is a major producer and exporter in the world. Phosphate fertilizer is also a major exporter because my country ranks second in the world in phosphorus resource reserves and ranks first in the world in production. Only potash fertilizer has limited domestic potassium resource reserves. More than half of the potash fertilizer used in my country needs to be imported from overseas, and more than 56% of cultivated land is still in a potassium-deficient state. In addition, due to the high degree of monopoly of potash fertilizer abroad, most of the production capacity is in the hands of the three countries, with a monopoly rate of nearly 70%. Therefore, my country's potash fertilizer supply is often hit by price fluctuations, which is extremely unfavorable to agricultural development.

[0004] In the process of graphite production, a large amount of graphite tailings waste will be generated. The accumulation of graphite tailings occupies a large amount of land, causes land and air pollution, and also poses certain safety hazards. Graphite is a non-renewable one-time energy source, and the rational development and utilization of graphite tailings is crucial.

[0005] Silicon fertilizer is a source of nutrition for many plants and can be used as a soil conditioner to improve soil conditions. Potassium fertilizer plays a supporting role in promoting photosynthesis and enzyme activity during plant growth. Most of my country's soils lack silicon and potassium, and the use of silicon and potassium fertilizers is very important for improving soil yield. Summary of the invention

[0006] In view of the above-mentioned deficiencies in the prior art, the present invention provides a method for preparing silicon-potassium fertilizer using graphite tailings, which reduces land and air pollution, reduces manufacturing costs and increases crop yields.

[0007] The technical solution adopted by the present invention is: A method for preparing silicon-potassium fertilizer using graphite tailings, Graphite tailings are ground; After grinding, add the additives and boil while stirring; After stirring, microwave treatment was performed; After microwave treatment, add food waste for re-grinding; The product is then ground to obtain silicon-potassium fertilizer.

[0008] Preferably, the particle size of the product after grinding the graphite tailings is below 200 meshes.

[0009] Preferably, the auxiliary agent is potassium carbonate, potassium hydroxide, sodium carbonate and sodium hydroxide, and a mixture of any two substances.

[0010] Heating and continuous stirring can fully mix the additive and graphite tailings; Preferably, the mass ratio of the grinding product of the graphite tailings to the additive is 10:1, and the grinding product is boiled in a container at a constant temperature of 100 degrees Celsius while being continuously stirred; The cooked product was subjected to microwave treatment at 500 watts for 30 minutes in a muffle furnace to increase the dissolution rate of silicon and potassium; Preferably, the kitchen waste is a mixture of fruit peels and tea leaves.

[0011] Preferably, the mass ratio of graphite tailings to kitchen waste is 3:1.

[0012] Grinding in a mill or other grinding equipment separates the agglomerated product and the product is ground to a size below 325 mesh; the product reaches the particle size required for subsequent use as a fertilizer.

[0013] The ground products are packaged and made into finished silicon-potassium fertilizers.

[0014] The beneficial effects of the present invention compared with the prior art are as follows: The present invention discloses a method for preparing silicon-potassium fertilizer by utilizing graphite tailings. The silicon-potassium fertilizer is prepared by using graphite tailings as raw materials. The graphite tailings have high silicon and potassium contents. The silicon dioxide and potassium oxide in the graphite tailings can provide silicon and potassium elements as raw materials for preparing the silicon-potassium fertilizer. A large amount of graphite tailings can be consumed to prepare the silicon-potassium fertilizer, thereby realizing the recycling of graphite tailings and kitchen waste. Adding an auxiliary agent reduces the heating temperature, reduces energy consumption, reduces manufacturing costs, reduces land and air pollution, and has significant social and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the process flow of preparing silicon-potassium fertilizer using graphite tailings. DETAILED DESCRIPTION

[0016] The present invention is described in detail below with reference to the accompanying drawings and embodiments: Attached Figure 1 It can be seen that a method for preparing silicon-potassium fertilizer using graphite tailings comprises the following steps: Step 1, grinding graphite tailings; Step 2, add additives after grinding and cook while stirring; Step 3, stirring and then subjecting to microwave treatment; Step 4, adding kitchen waste to be re-grinded after microwave treatment; Step 5, grinding the product again to obtain silicon-potassium fertilizer product.

[0017] Preferably, the particle size of the product after grinding the graphite tailings is below 200 meshes.

[0018] Preferably, the auxiliary agent is potassium carbonate, potassium hydroxide, sodium carbonate and sodium hydroxide, and a mixture of any two substances.

[0019] The auxiliary agent can be a single agent or a mixture of two agents. The ratio of auxiliary agents mainly considers economic factors and the amount of potassium provided and solubility. According to the price, the four auxiliary agents are: potassium carbonate, potassium hydroxide, sodium hydroxide, and sodium carbonate. Potassium carbonate and potassium hydroxide can provide potassium sources, but they are expensive, so the ratio can be adjusted according to the demand for potassium content and budget. For example, the combination of potassium hydroxide and sodium hydroxide can increase the potassium source and reduce costs. If you want to reduce costs, you can increase the ratio of sodium hydroxide.

[0020] Silicon-oxygen tetrahedrons can form macromolecules by bonding with each other through four oxygen bridges, but mixing silicon dioxide with alkali can form end groups, that is, breaking the silicon-oxygen covalent bonds in advance. The more doping, the more chains are broken, and the more structural defects the silicon dioxide crystal has, so the melting point is lowered. The required calcination temperature is lowered, and energy consumption is reduced.

[0021] Heating and continuous stirring can fully mix the additives, food waste and graphite tailings; Silicon dioxide in graphite tailings reacts with potassium carbonate or potassium hydroxide. Potassium in graphite tailings exists in the form of potassium oxide, which is easily soluble in water, and potassium in kitchen waste exists in the form of potassium ions.

[0022] Under high temperature conditions, the additive is K 2 CO 3 hour: SiO 2 + K 2 CO 3 = K 2 SiO 3 + CO 2 ↑; Under high temperature conditions, when the additive is KOH: SiO 2 + 2KOH = K 2 SiO 3 + H 2 O; Preferably, the mass ratio of graphite tailings to additives is 10:1, and the tailings are boiled in a container at a constant temperature of 100 degrees Celsius while being continuously stirred; The purpose of boiling is: heating can make the reactant molecules more active, increase their movement speed and collision frequency, and thus accelerate the chemical reaction. During the mixing process, this helps to quickly mix and evenly distribute the different components. As the temperature increases, the viscosity of the material usually decreases and the fluidity increases. This helps to reduce the resistance of the material during the mixing process, making it easier to stir and mix evenly. By heating and stirring, the reaction liquid can be kept within a stable temperature and pH range, thereby controlling the reaction rate and the composition of the reaction products. This helps to ensure the stability and repeatability of the mixing process. It can be adjusted according to the processing volume of graphite tailings and the size of the container, and can be initially set to 10 minutes.

[0023] The optimal mass ratio of medical stone for preparing silicon fertilizer additive is 10:0.5. Combined with the content of silicon dioxide in graphite tailings in actual conditions, the preferred ratio is 10:1.

[0024] The cooked product was subjected to microwave treatment at 500 watts for 30 minutes in a muffle furnace to increase the dissolution rate of silicon and potassium; The purpose of microwave treatment is to make the graphite tailings react with the additives to generate water-soluble silicon (refer to the graphite tailings and additives reaction equation above) so that the reaction reaches the required temperature. Other heating methods can be used to reach the required temperature for the reaction, but based on the comprehensive consideration of the microwave muffle furnace structure, the microwave treatment method is the best.

[0025] The condition for generating water-soluble silicon ions is that silicon dioxide and alkali react under high temperature conditions to generate soluble silicates. Potassium ions exist in the form of potassium oxide in graphite tailings and in the form of potassium ions in kitchen waste, and are themselves soluble potassium ions.

[0026] Preferably, the kitchen waste is a mixture of fruit peels and tea leaves.

[0027] The purpose of mixing kitchen waste with peels and tea residues is to provide sufficient potassium for the preparation of silicon-potassium fertilizers. Other waste that can provide potassium or trace elements required by plants can also be used instead, such as coffee grounds and vegetable roots and stems. Peels and tea residues are chosen because they are easier to obtain in large quantities, low in cost, and can be more conveniently decomposed and absorbed by plants. Tea residues contain fewer viruses, microorganisms, and parasite eggs than other wastes. Tea residues contain tea polyphenols, caffeine and other substances that can inhibit the growth of some pathogens and pests. The addition of peels and tea residues can contain more potassium than silicon-potassium fertilizers prepared using graphite tailings alone, and can better meet the growth needs of plants.

[0028] Preferably, the mass ratio of graphite tailings to kitchen waste is 3:1. is the mass ratio of graphite tailings to undehydrated kitchen waste.

[0029] The potassium content of food waste generally does not change after dehydration. The main purpose of dehydrating food waste is to remove the water in it to reduce weight, facilitate handling and transportation. In this process, the solid components in the garbage, including nutrients such as potassium, are usually retained. The quality of dehydrated food waste may be affected by some factors, such as temperature, pressure, dehydration time, etc. Different temperatures, pressures, and dehydration times may have different qualities. The mass ratio of graphite tailings to food waste (after dehydration) needs to be determined based on the dehydration treatment equipment in the actual situation.

[0030] Garbage treatment plants purchase kitchen waste. Domestically, garbage treatment plants generally use food waste dehydration sorting machines to sort and dehydrate food waste. Tea residues can be vacuum packaged, and fruit peels can be refrigerated or frozen. Directly purchase dehydrated kitchen waste and transport it directly.

[0031] The optimal ratio of graphite tailings: tea residue: peel is 3.916:0.28:1; The optimal ratio of tea residue to peel is 1:3.57.

[0032] Step 1. The ideal carbon-nitrogen ratio of fertilizer is between 20:1 and 40:1. The best carbon-nitrogen ratio is considered to be 24:1. Assuming the mass of graphite tailings is A, tea residue is B, and fruit peel is C, the carbon-nitrogen ratio of fruit peel, tea residue and graphite tailings is obtained: A+7.9C=42.2B.

[0033] After research and search, we found that the carbon content in graphite tailings is 1.7%, and the nitrogen content is extremely low and can be ignored. The organic carbon content in tea residue is 28.1%, and the nitrogen content is 4.16%. The organic carbon content in fruit peel is 40.31%, and the nitrogen content is 1.12%. Let the mass of graphite tailings be A, tea residue be B, and fruit peel be C.

[0034] Therefore, the total carbon content in the mixed fertilizer is: 1.7%A+28.1%B+40.31%C, and the total nitrogen content is: 4.16%B+1.12%C.

[0035] Since the optimal carbon-nitrogen ratio is considered to be 24:1, the carbon-nitrogen ratio of graphite tailings and kitchen waste fertilizer is set to 24:1. That is, 1.7%A+28.1%B+40.31%C / 4.16%B+1.12%C=24. After conversion, we get: A+7.9C=42.2B.

[0036] Step 2: According to national standards, the effective silicon content of silicon fertilizer must be above 40%. Assuming the total mass of kitchen waste is D, based on the effective silicon content, it can be concluded that: A>2D.

[0037] The silicon content in graphite tailings is about 60%, while there is no silicon in kitchen waste. Let the mass of graphite tailings be A, and the total mass of kitchen waste (i.e. tea dregs and fruit peels) be D (D=B+C).

[0038] The effective silicon content in the mixed fertilizer is 60%A, and the total mass is A+D. The effective silicon in the mixed fertilizer must be above 40%, so 60%A / A+D>40%. After conversion, we get: A / D>2, that is, A>2D.

[0039] Step 3: Fertilizers with a potassium content of more than 5% per kilogram belong to the category of medium-element fertilizers. Based on the potassium content, it can be concluded that: A < 12.35C-1.18B.

[0040] The potassium content in graphite tailings is about 4.15%, the potassium content in tea residue is about 4%, and the potassium content in fruit peel is about 15.5%. Let the mass of graphite tailings be A, the mass of tea residue be B, and the mass of fruit peel be C.

[0041] The potassium content in the mixed fertilizer is 4.15%A+4%B+15.5%C, and the total mass is A+B+C, so 4.15%A+4%B+15.5%C / A+B+C>5%. After conversion, we get: A<12.35C-1.18B.

[0042] Step 4: Substitute steps 1, 2, and 3 to obtain 0.25<B / C<0.47. The specific steps are as follows: In 1: A+7.9C=42.2B is converted to A=42.2B-7.9C.

[0043] In 2: A>2D, (D=A+B), replace A in A>2D with A=42.2B-7.9C in 1 and we get 42.2B-7.9C>2A+2B→40.2B>9.9C→B / C>0.25.

[0044] In 3: A<12.35C-1.18B. Replace the A in A<12.35C-1.18B with A=42.2B-7.9C in 1 and we get 42.2B-7.9C<12.35C-1.18B→43.38B<20.25C→B / C<0.47.

[0045] From B / C>0.25 in 2 and B / C<0.47 in 3, we can get 0.25<B / C<0.47.

[0046] Represent A in 1 with B and C, and substitute A>2D in 2, and A<12.35C-1.18B in 3; Where D=B+C; It turns out that 0.25<B / C<0.47.

[0047] 5. Increase the potassium content as much as possible, so B / C is taken as 0.28, and A:B:C=3.916:0.28:1; 6. Taking all the above factors into consideration, A:D=3.06:1, so the mass ratio of graphite tailings to kitchen waste is 3:1.

[0048] The kitchen waste added to the re-grinding must be tea dregs and peels that have been fermented and dried, because kitchen waste may contain some harmful microorganisms, such as pathogens, parasite eggs, etc. Through fermentation treatment, these harmful microorganisms can be effectively removed by utilizing high temperature and the inhibitory effect of microorganisms to ensure the biological safety of organic fertilizers. During the fermentation process, microorganisms will decompose the organic matter in the kitchen waste and release nutrients, such as nitrogen, phosphorus, potassium, etc. These nutrients are important elements required for plant growth. Through fermentation treatment, these nutrients can be converted into a form that is easy for plants to absorb and utilize, thereby increasing the nutrient content and utilization rate of organic fertilizers.

[0049] Grinding in a mill or other grinding equipment separates the agglomerated product and the product is ground to a size below 325 mesh; the product reaches the particle size required for subsequent use as a fertilizer.

[0050] The ground products are packaged and made into finished silicon-potassium fertilizers.

[0051] According to the ratio calculation in the previous article, it is preliminarily predicted that the effective silicon content in the finished product is above 40%, and the potassium content is above 5%. The effective silicon and potassium content in the finished product can be measured by a spectrophotometer.

[0052] The silicon dioxide in graphite tailings is not soluble in water and cannot be absorbed by plants. By adding alkali under high temperature conditions, the water-insoluble silicon dioxide can be converted into soluble silicates and absorbed by plants. Although potassium oxide in graphite tailings is soluble, the content is low. By adding kitchen waste, the content of soluble potassium can be increased.

[0053] The invention discloses a method for preparing silicon-potassium fertilizer by utilizing graphite tailings. The silicon-potassium fertilizer is prepared by using graphite tailings as raw materials. The silicon and potassium contents in the graphite tailings are relatively high. The silicon dioxide and potassium oxide in the graphite tailings can provide silicon and potassium elements as raw materials for preparing the silicon-potassium fertilizer. A large amount of graphite tailings can be consumed to prepare the silicon-potassium fertilizer, thereby reducing the manufacturing cost and having significant social and economic benefits.

[0054] The present invention uses graphite tailings to prepare silicon-potassium fertilizers. The graphite tailings are used as raw materials mainly to provide silicon and potassium sources. The content of silicon and potassium in the graphite tailings is very high. Most of the land lacking silicon also lacks potassium, so kitchen waste is added to provide more potassium sources.

[0055] The present invention uses graphite tailings to prepare silicon-potassium fertilizer, which reduces the manufacturing cost of preparing silicon fertilizer. Since graphite tailings belong to solid waste, the cost is extremely low. If it is prepared from other raw materials (such as water glass), it is not as low as directly using graphite tailings (solid waste) as raw materials to prepare silicon fertilizer.

[0056] The present invention utilizes graphite tailings to prepare a method for silicon-potassium fertilizer, thereby reducing air and environmental pollution. Due to the need to produce a large amount of graphite for national and economic development, the production of graphite will produce a large amount of graphite tailings, and the dust generated by the large amount of accumulation of graphite tailings will cause air pollution, and the accumulation of graphite tailings infiltrating the soil will cause environmental pollution. The use of graphite tailings as raw materials to prepare silicon-potassium fertilizers can consume a large amount of graphite tailings, thereby reducing the pollution of graphite tailings to the environment. Kitchen waste belongs to organic matter, while graphite tailings belong to inorganic matter. Inorganic fertilizers usually have a high nutrient content, and their composition is relatively simple. This clear nutrient composition enables inorganic fertilizers to be quickly absorbed and utilized by plants, meeting the needs of rapid growth of crops. In contrast, although organic fertilizers also contain a variety of nutrients, their content is relatively low, and the decomposition rate is slow, and it takes a long time to be absorbed and utilized by plants. And the total amount of kitchen waste is small, while the amount of graphite tailings is large.

[0057] The above is only a preferred embodiment of the present invention, and does not limit the structure of the present invention in any form. Any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention are within the scope of the technical solution of the present invention.

Claims

1. A method for preparing silicon-potassium fertilizer using graphite tailings, characterized in that: The steps include: Step 1, grinding graphite tailings; Step 2, after grinding, add auxiliary agent and boil while stirring; Step 3, stirring and then subjecting to microwave treatment; Step 4, adding kitchen waste to be re-grinded after microwave treatment; Step 5, grinding the product again to obtain silicon-potassium fertilizer product.

2. The method for preparing silicon-potassium fertilizer using graphite tailings according to claim 1, wherein: The particle size of the product after the first grinding of graphite tailings is below 200 mesh.

3. The method for preparing silicon-potassium fertilizer using graphite tailings according to claim 1, wherein: The auxiliary agent is potassium carbonate, potassium hydroxide, sodium carbonate, sodium hydroxide, or a mixture of any two substances; Heating and continuous stirring can ensure that the additive and graphite tailings are thoroughly mixed.

4. The method for preparing silicon-potassium fertilizer from graphite tailings according to claim 1, wherein: The mass ratio of the grinding product to the additive after grinding the graphite tailings is 10:1, and it is boiled in a constant temperature container at 100 degrees Celsius while being continuously stirred.

5. The method for preparing silicon-potassium fertilizer using graphite tailings according to claim 1, wherein: The stirred product was microwaved in a muffle furnace at 500 W for 30 minutes.

6. The method for preparing silicon-potassium fertilizer from graphite tailings according to claim 1, characterized in that: The kitchen waste is a mixture of fruit peels and tea leaves; The mass ratio of graphite tailings to kitchen waste is 3:1; Grinding in a mill or other grinding equipment to separate the agglomerated product, and grinding the product to a size below 325 mesh; making the product reach the particle size required for subsequent use as fertilizer; The ground products are packaged and made into finished silicon-potassium fertilizers.

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