Integrated dehydration equipment, dehydration method and germanium enrichment method

Abstract

The invention discloses integrated dehydration equipment, a dehydration method and a germanium enrichment method, belongs to the technical field of dehydration, and aims to solve the problem of poor dehydration effect of lignite in the prior art. The equipment comprises a dehydration cylinder, a heating ring, a microwave generator and a refrigerator. The method comprises the following steps: feeding lignite and an ethanol solution into a freezing microwave chamber, starting a refrigerator and a heating ring at the same time, and freezing the crushed and screened lignite and the ethanol solution; the first heating chamber, the freezing microwave chamber and the second heating chamber are communicated, hot air in the first heating chamber and the second heating chamber is supplied into the freezing microwave chamber, and the frozen lignite is heated and dehydrated in the freezing microwave chamber; and starting the microwave generator. The method can be used for lignite dehydration.

Description

Technical Field

[0001] The present invention belongs to the technical field of dehydration, and in particular relates to an integrated dehydration device, a dehydration method and a germanium enrichment method. Background Art

[0002] Coal is an important component of coal resources. However, the moisture content of lignite is usually as high as 30% to 60%, which seriously restricts its efficient utilization.

[0003] At present, traditional lignite dehydration technology mainly includes mechanical extrusion. For lignite with a hydrophilic surface and developed internal pores, it is difficult to effectively remove moisture from it, and the dehydration effect is poor. Summary of the Invention

[0004] In view of the above analysis, the present invention aims to provide an integrated dehydration device, a dehydration method and a germanium enrichment method, which are used to solve the problem of poor lignite dehydration effect in the prior art.

[0005] The purpose of the present invention is mainly achieved through the following technical solutions.

[0006] The present invention provides an integrated dehydration device, comprising a dehydration cylinder, a heating ring, a microwave generator and a refrigerator. The heating ring is used to heat the inner cavity of the dehydration cylinder, the microwave generator is used to provide microwaves into the dehydration cylinder, and the refrigerator is used to cool the inner cavity of the dehydration cylinder.

[0007] Furthermore, the integrated dehydration equipment also includes a first insulation plate and a second insulation plate arranged in the dehydration cylinder. The first insulation plate and the second insulation plate are arranged in sequence from top to bottom, dividing the inner cavity of the dehydration cylinder from top to bottom into a first heating chamber, a freezing microwave chamber and a second heating chamber.

[0008] Furthermore, the number of heating rings is two.

[0009] Furthermore, one of the two heating coils is sleeved on the outer wall of the first heating chamber, and the other is sleeved on the outer wall of the second heating chamber.

[0010] Furthermore, the microwave generator and the refrigerator are sleeved on the outer wall of the freezing microwave chamber.

[0011] Furthermore, there are multiple refrigerators, and the multiple refrigerators are arranged at equal intervals along the axial direction of the dehydration cylinder.

[0012] Furthermore, there are multiple microwave generators, and the multiple microwave generators are arranged at equal intervals along the axial direction of the dehydration cylinder.

[0013] Furthermore, the microwave generators and refrigerators are alternately arranged.

[0014] In a second aspect, the present invention further provides an integrated dehydration method, using the above-mentioned integrated dehydration equipment, the integrated dehydration method comprises the following steps:

[0015] Step a: feeding the crushed and screened lignite and the ethanol solution into a freezing microwave chamber, while simultaneously turning on a refrigerator and a heating coil, wherein the refrigerator cools the freezing microwave chamber and the heating coil heats the first heating chamber and the second heating chamber, thereby freezing the crushed and screened lignite and the ethanol solution;

[0016] Step b: closing the refrigerator, connecting the first heating chamber, the freezing microwave chamber, and the second heating chamber, supplying hot air from the first heating chamber and the second heating chamber into the freezing microwave chamber, heating and dehydrating the frozen lignite in the freezing microwave chamber, so that the frozen water directly sublimates to form water vapor;

[0017] Step c: turning off the heating coil and turning on the microwave generator to perform microwave dehydration on the heated and dehydrated lignite.

[0018] In a third aspect, the present invention further provides a method for enriching germanium, which uses the above-mentioned integrated dehydration method to dehydrate lignite.

[0019] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0020] A) The integrated dehydration equipment provided by the present invention integrates multiple functions of freezing, heating dehydration and microwave dehydration in the same cylinder (dehydration cylinder), which can meet the dehydration process requirements of lignite during the pretreatment process, has a compact structure and is easy to operate.

[0021] B) The integrated dehydration method provided by the present invention allows the free water and some bound water in the lignite to crystallize at low temperatures. The volume of the ice crystals expands by about 9% compared to liquid water, and can open the original closed pores through "mechanical compression" and even destroy part of the organic matter encapsulation structure, creating conditions for the exposure of germanium. At the same time, ethanol can lower the freezing point of water, making the ice crystals smaller and more evenly distributed, avoiding excessive damage to the pores by large ice crystals and preventing structural collapse.

[0022] C) The integrated dehydration method provided by the present invention is different from conventional hot air dehydration. When liquid water evaporates, the "capillary force" will pull the organic matter in the lignite to shrink, causing pore collapse. In contrast, in sublimation dehydration, ice crystals directly turn into water vapor. Without the "contraction force" of liquid water migration, the original pores opened by ice crystals during the freezing stage can be fully preserved. At the same time, the vacuum environment can also reduce the contact between the lignite and air, preventing the oxidation of organic matter and clogging of the pores.

[0023] D) The integrated dehydration method provided by the present invention uses microwaves to heat through "polar molecular oscillations". The residual moisture and organic polar groups in the lignite absorb the microwave energy, and the heat is transferred from the inside of the lignite to the outside (the opposite of the traditional "external heating" of hot air), forming a "high inside and low outside" temperature gradient. The residual moisture inside is quickly evaporated by the heat, generating micro-air pressure, which forms an "outward expansion" force on the pores, causing the original micropores (<2nm) to expand into mesopores (2nm~50nm), and the mesopores to expand into macropores (>50nm). The connectivity of the pores after expansion is significantly improved. At the same time, the medium temperature (60℃~80℃) can also avoid the softening and collapse of the lignite organic matter (the softening point of lignite organic matter is mostly above 100℃), taking into account both dehydration efficiency and structural stability.

[0024] In the present invention, the above-mentioned technical solutions can be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages will become apparent from the description or be understood through practice of the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the embodiments of the description and the contents particularly pointed out in the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like parts throughout the drawings.

[0026] Figure 1 A schematic structural diagram of the integrated dehydration equipment provided in Example 1 of the present invention;

[0027] Figure 2 This is a schematic structural diagram of the first insulation plate of the integrated dehydration device provided in Example 1 of the present invention when it is in freezing mode;

[0028] Figure 3 for Figure 2 AA cross-sectional view;

[0029] Figure 4 This is a schematic structural diagram of the first insulation plate when the integrated dehydration equipment provided in Example 1 of the present invention is in heating mode;

[0030] Figure 5 for Figure 4 BB cross-sectional view.

[0031] Reference numerals:

[0032] 1-Center shaft; 2-Heating ring; 3-Microwave generator; 4-Refrigerator; 5-First insulation plate; 51-First elliptical sealing ring; 52-Second elliptical sealing ring; 53-Elliptical rotating plate; 6-Second insulation plate; 7-First heating chamber; 8-Freezing microwave chamber; 9-Second heating chamber; 10-Shaft driver. DETAILED DESCRIPTION

[0033] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0034] During lignite dehydration, the pore structure often undergoes adverse changes, such as shrinkage. An ideal dehydration process should not only efficiently remove water but also optimize the lignite's pore structure and increase porosity to enhance its performance in subsequent applications, such as increasing the permeability of coalbed methane. However, current technologies struggle to achieve this goal and fail to meet the demand for improved pore structure for efficient and clean lignite utilization.

[0035] Example 1

[0036] This embodiment provides an integrated dehydration device. Figure 1 , including a dehydration cylinder 1, a heating ring 2, a microwave generator 3 and a refrigerator 4. The heating ring 2 is used to heat the inner cavity of the dehydration cylinder 1, the microwave generator 3 is used to provide microwaves into the dehydration cylinder 1, and the refrigerator 4 is used to cool the inner cavity of the dehydration cylinder 1.

[0037] Compared with the existing technology, the integrated dehydration equipment provided in this embodiment integrates multiple functions of freezing, heating dehydration and microwave dehydration in the same cylinder (dehydration cylinder 1), which can meet the dehydration process requirements of lignite during the pretreatment process, has a compact structure and is easy to operate.

[0038] It is worth noting that in the process of switching between the freezing mode and the heating mode, it is necessary to avoid water from changing from solid to liquid and then to gas, but it is more inclined to change water directly from solid to gas. However, heating dehydration requires a certain heating time, and there is inevitably a time difference from freezing dehydration to heating dehydration. Therefore, the above-mentioned integrated dehydration equipment also includes a first insulation plate 5 and a second insulation plate 6 arranged in the dehydration cylinder 1. The first insulation plate 5 and the second insulation plate 6 are arranged in sequence from top to bottom along the setting direction, dividing the inner cavity of the dehydration cylinder 1 into a first heating chamber 7, a freezing microwave chamber 8 and a second heating chamber 9 from top to bottom.

[0039] Exemplarily, there are two heating rings 2 , one of which is sleeved on the outer wall of the first heating chamber 7 , and the other is sleeved on the outer wall of the second heating chamber 9 .

[0040] The microwave generator 3 and the refrigerator 4 are sleeved on the outer wall of the freezing microwave chamber 8 .

[0041] From the perspective of freezing uniformity, the number of the above-mentioned refrigerators 4 is multiple, and the multiple refrigerators 4 are arranged at equal intervals along the axial direction of the dehydration cylinder 1.

[0042] Accordingly, considering the uniformity of microwave drying, there are multiple microwave generators 3 , and the multiple microwave generators 3 are arranged at equal intervals along the axial direction of the dehydration cylinder 1 .

[0043] From the perspective of layout, the microwave generators 3 and the refrigerators 4 are arranged alternately.

[0044] In order to enable the first heating chamber 7, the freezing microwave chamber 8 and the second heating chamber 9 to be connected, the structures of the first insulation plate 5 and the second insulation plate 6 are the same in structure and shape. Specifically, the first insulation plate 5 and the second insulation plate 6 are both elliptical in shape, and both include a first elliptical sealing ring, a second elliptical sealing ring and an elliptical rotating plate. Different from the existing method of controlling the connection between two spaces through a valve, the insulation plate with this structure does not involve electrical air. It only needs to be provided with a power device for driving the elliptical rotating plate to rotate outside the dehydration cylinder 1, without involving electrical control inside the dehydration cylinder 1.

[0045] The integrated dehydration equipment is in freezing mode, see Figures 2 to 3 , the edges of the elliptical rotating plate are inserted between the first elliptical sealing ring and the second elliptical sealing ring, and are sealed with the first elliptical sealing ring and the second elliptical sealing ring, the major axis of the elliptical rotating plate coincides with the major axis of the first elliptical sealing ring and the major axis of the second elliptical sealing ring, and the minor axis of the elliptical rotating plate coincides with the minor axis of the first elliptical sealing ring and the minor axis of the second elliptical sealing ring.

[0046] The integrated dehydration equipment is in heating mode, see Figures 4 and 5 , part of the edge of the elliptical rotating plate is inserted between the first elliptical sealing ring and the second elliptical sealing ring, and is sealed with the first elliptical sealing ring and the second elliptical sealing ring, and another part of the edge of the elliptical rotating plate has a gap with the first elliptical sealing ring and the second elliptical sealing ring, serving as a connecting channel between the first heating chamber 7, the freezing microwave chamber 8 and the second heating chamber 9, the major axis of the elliptical rotating plate coincides with the minor axis of the first elliptical sealing ring and the minor axis of the second elliptical sealing ring, and the minor axis of the elliptical rotating plate coincides with the major axis of the first elliptical sealing ring and the major axis of the second elliptical sealing ring.

[0047] It can be understood that in order to drive the rotation of the first turn plate and the second turn plate, the above-mentioned integrated dehydration equipment also includes a shaft driver 10 and a central shaft 1. One end of the central shaft 1 is fixedly connected to the output shaft of the shaft driver 10, and the other end of the central shaft 1 passes through the dehydration cylinder 1 and is fixedly connected to the elliptical turn plate in the first turn plate and the elliptical turn plate in the second turn plate in turn. The shaft driver 10 drives the elliptical turn plate to rotate through the central shaft 1.

[0048] Example 2

[0049] This embodiment provides an integrated dehydration method, using the integrated dehydration equipment provided in Example 1. The integrated dehydration method includes the following steps:

[0050] Step a: The crushed and screened lignite is mixed with a 5% to 10% ethanol solution (as an ice crystal regulator) at a solid-liquid ratio of 1:1 to 1.5 and then supplied to a freezing microwave chamber 8. Then, the refrigerator 4 and the heating coil 2 are simultaneously turned on. The refrigerator 4 cools the freezing microwave chamber 8, and the heating coil 2 heats the first heating chamber 7 and the second heating chamber 9. The crushed and screened lignite and the ethanol solution are frozen at a temperature of -20°C to -30°C for 2 to 4 hours.

[0051] Step b: closing the refrigerator 4, connecting the first heating chamber 7, the freezing microwave chamber 8, and the second heating chamber 9, rapidly supplying the hot air in the first heating chamber 7 and the second heating chamber 9 into the freezing microwave chamber 8, heating and dehydrating the frozen lignite in the freezing microwave chamber 8 for 4 to 6 hours, so that ice crystals directly sublime to form water vapor;

[0052] Step c: turn off the heating ring 2, turn on the microwave generator 3, and perform microwave dehydration on the heated and dehydrated lignite. The power of the microwave dehydration is 300W to 500W, the temperature is 60℃ to 80℃, and the microwave irradiation is 30min to 60min (intermittent, microwave irradiation for 10min and stop for 2min).

[0053] Compared with the existing technology, the integrated dehydration method provided in this embodiment, on the one hand, causes the free water and part of the bound water in the lignite to crystallize at low temperatures, and the volume of the ice crystals expands by about 9% compared to liquid water. It can open the original closed pores through "mechanical extrusion" and even destroy part of the organic matter wrapping structure, creating conditions for the exposure of germanium. At the same time, ethanol can lower the freezing point of water, making the ice crystals smaller and more evenly distributed, avoiding excessive damage to the pores by large ice crystals and preventing structural collapse.

[0054] On the other hand, in traditional hot air dehydration, when liquid water evaporates, the "capillary force" will pull the organic matter of the lignite to shrink, causing pore collapse. In sublimation dehydration, ice crystals directly turn into water vapor, and there is no "contraction force" of liquid water migration, which can completely preserve the original pores opened by ice crystals during the freezing stage. At the same time, the vacuum environment can also reduce the contact between lignite and air, preventing organic matter from oxidizing and clogging the pores.

[0055] On the other hand, microwaves heat through "polar molecular oscillations", and the residual moisture and organic polar groups in the lignite absorb microwave energy. Heat is transferred from the inside to the outside of the lignite (the opposite of traditional hot air "external heating"), forming a "high inside and low outside" temperature gradient. The internal residual moisture evaporates rapidly due to heat, generating micro-air pressure, which forms an "outward expansion" force on the pores, causing the original micropores (<2nm) to expand into mesopores (2nm~50nm), and the mesopores to expand into macropores (>50nm), and the connectivity of the pores after expansion is significantly improved. At the same time, medium temperature (60℃~80℃) can also avoid the softening and collapse of lignite organic matter (the softening point of lignite organic matter is mostly above 100℃), taking into account both dehydration efficiency and structural stability.

[0056] Example 3

[0057] This embodiment provides a method for enriching germanium, and uses the integrated dehydration method provided in Example 2 to dehydrate lignite.

[0058] Compared with the prior art, the beneficial effects of the germanium enrichment method provided in this embodiment are substantially the same as the beneficial effects of the integrated dehydration method provided in Example 2, and are not described in detail here.

[0059] Specifically, the following steps are included:

[0060] Step 1: crushing and screening the lignite to reduce the particle size to less than 0.2 mm, and dehydrating the screened lignite;

[0061] Step 2: mixing lignite with an alkali solution (for example, the alkali solution is sodium hydroxide, potassium hydroxide, lithium hydroxide, or sodium pyrophosphate) at a solid-liquid ratio of 1:4 g / ml to 1:16 g / ml, heating the mixture to 60° C. to 120° C. and stirring the mixture at a speed of 20 rad / min to 40 rad / min for 30 to 240 minutes to obtain a reaction mixture, wherein the concentration of the alkali solution is 0.5 mol / L to 2 mol / L to ensure sufficient leaching of the humic acid germanium complex while preventing leaching of silicon, aluminum, and other substances that are difficult to separate;

[0062] Step 3: filtering and separating the reaction mixture to obtain a first liquid phase and a first solid phase, wherein the first liquid phase includes a humic acid germanium complex, sodium ions, and iron ions, and the first solid phase includes inorganic components (e.g., C, Si, and Al) in addition to organic components in lignite;

[0063] Step 4: washing the first solid phase, dehydrating the washed first solid phase at a dehydration temperature of 65° C. to 75° C. (e.g., 70° C.), mixing the washing liquid of the first solid phase with the first liquid phase to obtain a first mixed liquid. By collecting the washing liquid of the first solid phase, the liquid containing germanium remaining in the first solid phase can be recycled, thereby further improving the extraction rate of germanium;

[0064] Step 5: mixing the first mixed solution with hydrochloric acid having a concentration of 0.8 mol / L to 1.5 mol / L, adjusting the pH value to 1 to 2, and allowing the mixture to stand until precipitation is complete. The pH adjustment can promote the precipitation of the humic acid germanium complex, thereby achieving preliminary enrichment of germanium and obtaining a precipitated mixed solution;

[0065] Step 6: Filter and separate the precipitated mixed solution to obtain a second liquid phase and a second solid phase;

[0066] Step 7: After dehydrating the second solid phase, perform oxygen-controlled ashing at a temperature of 400° C. to 800° C. for 90 min to 210 min, wherein the volume content of oxygen in the atmosphere used in the ashing process is 1% to 25%, preferably 10% to 20%;

[0067] Step 8: Mix the product after oxygen-controlled ashing with water (e.g., ultrapure water) at a solid-liquid ratio of 1:4 to 1:20, and heat to 30° C. to 45° C. to dissolve for 25 to 40 minutes, so that salt impurities such as sodium salt and calcium salt are dissolved in the water;

[0068] Step 9: filtering and separating the mixture obtained in step 8 to obtain a third solid phase and a third liquid phase, and dehydrating the third solid phase at a dehydration temperature of 65 to 75° C. (e.g., 70° C.) to obtain a germanium-containing product;

[0069] Step 10: The third liquid phase is crystallized to remove water from the third liquid phase to obtain a fourth solid phase. The fourth solid phase contains sodium chloride and calcium chloride, thereby enabling the recycling of sodium salts and calcium salts. The product after oxygen-controlled ashing is treated by a water immersion process to dissolve salt impurities such as sodium salts and calcium salts in water to obtain a solution containing NaCl and CaCl2, which is subsequently further utilized through crystallization. Salts such as NaCl and CaCl2 have good solubility in water and can achieve resource recycling.

[0070] Specifically, on the one hand, the carboxyl group (-COOH) and phenolic hydroxyl group (-OH) in the humic acid molecule have a great influence on the 4+ The coordination strength is much higher than that of Si 4+ , through selective dissolution in alkali solution, germanium preferentially forms soluble complexes (e.g., humic acid germanium complex, HA-Ge(OH)3 - ), while silicon remains in the residue (silicon dissolution rate <2%), thereby increasing the extraction rate of germanium and achieving the effect of separating germanium and silicon.

[0071] On the other hand, silicon dioxide-germanium dioxide solid solution is difficult to dissolve, and a large amount of acid is required to dissolve such solid solution, and germanium is extremely difficult to release because it is encapsulated therein. In the present invention, during the reaction process of lignite and alkali solution, since silicon remains in the residue, the formation of silicon dioxide-germanium dioxide solid solution can be avoided during the oxygen-controlled ashing process, thereby greatly reducing the subsequent acid consumption and, at the same time, improving the extraction rate of germanium.

[0072] On the other hand, during the oxygen-controlled ashing process, the original hydroxyl and carbonyl groups in the humic acid germanium are broken, the organic matter is decomposed to generate carbon dioxide and volatilize, and the coordination bonds of the humic acid germanium are broken, thereby releasing germanium from the organic matter, which is more conducive to the recovery of germanium.

[0073] It should be noted that by using the above method to enrich germanium, the enrichment factor of germanium in the product of oxygen-controlled ashing can reach more than 5 (for example, 5.1 to 5.6), and in the third solid phase, the enrichment factor of germanium can reach more than 38 (for example, 38 to 40).

[0074] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. An integrated dehydration device, characterized in that: The dehydration cylinder comprises a dehydration cylinder, a heating ring, a microwave generator and a refrigerator. The heating ring is used for heating the inner cavity of the dehydration cylinder, the microwave generator is used for providing microwaves into the dehydration cylinder, and the refrigerator is used for cooling the inner cavity of the dehydration cylinder.

2. The integrated dehydration equipment according to claim 1, characterized in that: The integrated dehydration equipment also includes a first insulation plate and a second insulation plate arranged in the dehydration cylinder. The first insulation plate and the second insulation plate are arranged in sequence from top to bottom, dividing the inner cavity of the dehydration cylinder into a first heating chamber, a freezing microwave chamber and a second heating chamber from top to bottom.

3. The integrated dehydration equipment according to claim 2, characterized in that: The number of the heating rings is two.

4. The integrated dehydration equipment according to claim 3, characterized in that: One of the two heating rings is sleeved on the outer wall of the first heating chamber, and the other is sleeved on the outer wall of the second heating chamber.

5. The integrated dehydration equipment according to claim 2, characterized in that: The microwave generator and the refrigerator are sleeved on the outer wall of the freezing microwave chamber.

6. The integrated dehydration equipment according to claim 5, characterized in that: There are multiple refrigerators, and the multiple refrigerators are arranged at equal intervals along the axial direction of the dehydration cylinder.

7. The integrated dehydration equipment according to claim 6, characterized in that: There are multiple microwave generators, and the multiple microwave generators are arranged at equal intervals along the axial direction of the dehydration cylinder.

8. The integrated dehydration equipment according to claim 7, characterized in that: The microwave generators and refrigerators are arranged alternately.

9. An integrated dehydration method, characterized in that: Using the integrated dehydration equipment according to any one of claims 2 to 8, the integrated dehydration method comprises the following steps: Step a: feeding the crushed and screened lignite and the ethanol solution into a freezing microwave chamber, while simultaneously turning on a refrigerator and a heating coil, wherein the refrigerator cools the freezing microwave chamber and the heating coil heats the first heating chamber and the second heating chamber, thereby freezing the crushed and screened lignite and the ethanol solution; Step b: closing the refrigerator, connecting the first heating chamber, the freezing microwave chamber, and the second heating chamber, supplying hot air from the first heating chamber and the second heating chamber into the freezing microwave chamber, heating and dehydrating the frozen lignite in the freezing microwave chamber, so that the frozen water directly sublimates to form water vapor; Step c: turning off the heating coil and turning on the microwave generator to perform microwave dehydration on the heated and dehydrated lignite.

10. A method for enriching germanium, characterized in that: The lignite is dehydrated using the integrated dehydration method as claimed in claim 9.

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