Production device and production method of glucolactone

Abstract

The glucolactone production device comprises a tank body, a hollow shaft body is arranged in the tank body, the bottom end of the hollow shaft body extends to the lower portion of the tank body, a rotating part used for driving the hollow shaft body to rotate is arranged on the bottom end of the hollow shaft body, and the hollow shaft body is connected with a plurality of flow dividing stirring pipes in a penetrating mode. A cold air header pipe is arranged in the hollow shaft body, cold air branch pipes are arranged in the flow dividing stirring pipes, a liquid supply part and a cold air supply part are arranged above the tank body, the liquid supply part is used for enabling water to flow into the hollow shaft body, and the cold air supply part is used for enabling cold air to flow into the cold air header pipe. According to the cooling tank, circulating water can keep a continuous low-temperature effect, so that materials in the tank body are effectively cooled.

Description

Technical Field

[0001] The invention relates to the technical field of gluconolactone processing, and in particular to a production device and a production method of gluconolactone. Background Art

[0002] Gluconolactone is used as a protein coagulant, acidulant, leavening agent, preservative, and in the production of cosmetics and toothpaste. In the production and processing technology of gluconolactone using calcium gluconate as raw material, after the gluconic acid solution obtained by hydrolysis with sulfuric acid is purified, it is necessary to use a crystallizer to stir and cool the solution to precipitate crystals. However, the existing crystallizer has a slow cooling efficiency and uneven cooling, which affects the production speed and quality of gluconolactone.

[0003] In the invention patent with publication number CN114225464B, a gluconolactone production and processing device and a gluconolactone production and processing process are disclosed. The crystallizer includes a crystallizer body, a feed pipe is arranged at the upper end of the crystallizer body, a hollow stirring shaft is arranged inside the crystallizer body, a hollow stirring blade is connected through the hollow stirring shaft, and cold water is injected into the hollow stirring shaft and the hollow stirring blade.

[0004] During the material cooling process, the above-mentioned device cools the material by circulating cold water into the interior of the hollow stirring shaft and the hollow stirring blades. However, during the water circulation process, the hollow stirring shaft and the hollow stirring blades absorb a large amount of heat, causing the water temperature to rise, making it difficult to continuously cool the material, which will still affect the production speed and quality of gluconolactone. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a production device and a production method for gluconolactone, and the specific technical scheme is as follows:

[0006] One of the purposes of the present invention is to provide a production device for gluconolactone, comprising a tank body, a hollow shaft body is arranged inside the tank body, the bottom end of the hollow shaft body extends to the lower part of the tank body, a rotating part for driving the hollow shaft body to rotate is arranged on the tank body, a plurality of flow splitting and stirring pipes are connected through the hollow shaft body, a cold air main pipe is arranged inside the hollow shaft body, a cold air branch pipe is arranged inside the flow splitting and stirring pipe, and both ends of the cold air branch pipe are connected to the cold air main pipe, a liquid supply part and a cold air supply part are arranged above the tank body, the liquid supply part is used for water to flow into the hollow shaft body, and the cold air supply part is used for cold air to flow into the cold air main pipe;

[0007] The hollow shaft is located at the upper part of the tank body and is connected with fan blades. When the hollow shaft is rotated, the fan blades rotate synchronously to generate negative pressure above the tank body, so that the gas inside the tank body can be drawn out of the tank body.

[0008] As an improvement of the above technical solution: a plurality of air outlet pipes are provided inside the tank body, the top ends of the air outlet pipes extend to the top side of the inner part of the hollow shaft body and are located below the fan blades, and the bottom ends of the air outlet pipes extend to the outside of the hollow shaft body and are located on the top side of the inner part of the tank body.

[0009] As an improvement of the above technical solution: the liquid supply part includes a liquid inlet pipe, a mounting top plate, a water tank and a second pump body, the bottom end of the liquid inlet pipe extends to the interior of the hollow shaft body, the water tank is mounted on the mounting top plate, a liquid passing groove is provided in the mounting top plate, the top end of the liquid inlet pipe extends into the liquid passing groove, the input end of the second pump body is connected to the interior of the water tank through a pipe, and the output end of the second pump body is connected to the liquid passing groove through a pipe.

[0010] As an improvement of the above technical solution: the cold air supply unit includes a refrigeration component and a first pump body, the refrigeration component is installed on the water tank, the input end of the first pump body is connected to the refrigeration component, and the output end of the first pump body is connected to the cold air main pipe through a pipeline.

[0011] As an improvement of the above technical solution: the liquid inlet pipe is provided with a tube-liquid cavity in an annular shape, and the two ends of the tube-liquid cavity respectively pass through the top and bottom ends of the liquid inlet pipe, and the top of the inner wall of the liquid inlet pipe is connected with an annular blocking block, and the inner top side of the hollow shaft body is also fixedly connected with a waterproof and breathable membrane layer, the top ends of the liquid inlet pipe and the air outlet pipe both pass through and extend to the top of the waterproof and breathable membrane layer, the top sides of the cold air main pipe and the air outlet pipe are both located on the inner side of the liquid inlet pipe, and the top end of the cold air main pipe passes through the waterproof and breathable membrane layer and extends to the top of the hollow shaft body.

[0012] As an improvement of the above technical solution: the rotating part includes a driving motor, which is installed on the top of the tank body, and the top output shaft of the driving motor is fixedly connected to the first gear. The top of the hollow shaft body extends to the top of the tank body and is connected to the second gear. The top side and bottom of the hollow shaft body rotate on the top side and bottom side of the tank body through bearings respectively. The bottom end of the hollow shaft body extends to the bottom of the tank body, and the first gear and the second gear are meshed.

[0013] As an improvement of the above technical solution: the top of the tank body is connected to an exhaust pipe connected to the interior of the tank body, the bottom of the tank body is connected to a discharge pipe, the tank body is also connected to a ventilation pipe and a feed funnel, the ventilation pipe is installed with a pressure relief valve, and the inner wall of the tank body is installed with an air pressure measuring gauge.

[0014] As an improvement of the above technical solution: the diversion stirring tubes are provided with two, the top end surface of one of the diversion stirring tubes is higher than the top end surface of the other diversion stirring tube, and a diversion plate inclined downward is connected to the inside of the hollow shaft near the bottom of the top end of the diversion stirring tube, and a plurality of diversion holes are opened on the diversion plate.

[0015] One of the objects of the present invention is to provide a method for producing gluconolactone, comprising the following steps:

[0016] Step 1, hydrolyzing calcium gluconate in a tank to obtain a gluconic acid solution;

[0017] Step 2, after the gluconic acid solution is allowed to stand, filtering to remove calcium sulfate precipitate in the gluconic acid solution;

[0018] Step 3, purifying the filtered gluconic acid solution;

[0019] Step 4: After concentrating the gluconic acid solution, inject it into the above-mentioned tank, stir it, and allow crystals to precipitate.

[0020] Beneficial effects of the present invention:

[0021] 1. During the stirring and cooling process in the tank, the hollow shaft body is driven to rotate by running the rotating part, and the first pump body and the second pump body are operated at the same time. The driving of the hollow shaft body can allow multiple shunt stirring tubes to drive the materials inside to stir. The cold water liquid in the water tank can be drawn through the second pump body to flow into the inside of the hollow shaft body and the shunt stirring tube, so that the hollow shaft body and the shunt stirring tube can absorb the heat in the material while stirring the material to cool the material; by running the first pump body, the cold air in the refrigeration part is transported to the cold air main pipe and the cold air branch pipe, and the cold air main pipe and the cold air branch pipe are cold treated by the cold water liquid flowing into the hollow shaft body and the shunt stirring tube, which makes the circulating water liquid maintain a continuous low temperature effect, thereby effectively cooling the material in the tank;

[0022] 2. When the hollow shaft rotates, the fan blades will also rotate synchronously to generate negative pressure above the tank. On the one hand, the hot air inside the tank can be discharged to the outside, and on the other hand, the heat on the surface of the hollow shaft and the split stirring tube can be taken away to maintain the low temperature effect of the hollow shaft and the split stirring tube.

[0023] 3. The water vapor generated in the hollow shaft and the split-flow stirring tube will be drawn out to the outer end of the outlet pipe by negative pressure, and then discharged to the outside of the tank through the exhaust pipe, so as to prevent the hot water vapor from affecting the cooling effect of the hollow shaft and the split-flow stirring tube during cooling. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0025] Figure 2 for Figure 1 A schematic diagram of the enlarged structure at A in the middle;

[0026] Figure 3 for Figure 1 A schematic diagram of the enlarged structure at B in the middle;

[0027] Figure 4 for Figure 1 Schematic diagram of the enlarged structure at C in the middle;

[0028] Figure 5 The present invention is a schematic diagram of the connection structure between the hollow shaft body, the air outlet pipe, and the cold air main pipe.

[0029] Figure numerals: 1, tank body; 101, exhaust pipe; 102, feed funnel; 103, discharge pipe; 104, ventilation pipe; 105, air pressure measuring meter; 2, hollow shaft; 3, driving motor; 31, first gear; 32, second gear; 4, exhaust pipe; 5, fan blade; 6, cooling main pipe; 7, diversion stirring pipe; 8, cooling branch pipe; 9, installation top plate; 91, liquid trough; 10, water tank; 11, refrigeration part; 12, first pump body; 13, second pump body; 14, liquid inlet pipe; 140, tube liquid cavity; 141, annular block; 15, waterproof and breathable membrane layer; 16, diverter plate; 161, diverter hole. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0031] Example

[0032] A production device and production method of gluconolactone, please refer to Figure 1-Figure 5 A production device for gluconolactone, comprising a tank body 1, a hollow shaft body 2 is arranged inside the tank body 1, the bottom end of the hollow shaft body 2 extends to the lower part of the tank body 1, and a rotating part for driving the hollow shaft body 2 to rotate is arranged on the tank body 1, a plurality of flow splitting and stirring pipes 7 are connected through the hollow shaft body 2, a cold air main pipe 6 is arranged inside the hollow shaft body 2, a cold air branch pipe 8 is arranged inside the flow splitting and stirring pipe 7, and both ends of the cold air branch pipe 8 are connected to the cold air main pipe 6, a liquid supply part and a cold air supply part are arranged above the tank body 1, the liquid supply part is used for circulating water into the hollow shaft body 2, and the cold air supply part is used for circulating cold air into the cold air main pipe 6;

[0033] The hollow shaft body 2 is located at the upper part of the tank body 1 and is connected to the fan blades 5. When the hollow shaft body 2 is rotated, the fan blades 5 rotate synchronously to generate negative pressure above the inside of the tank body 1, so that the gas inside the tank body 1 can be drawn out of the tank body 1, thereby effectively extracting the hot air inside the tank body 1.

[0034] In an optional embodiment: a plurality of air outlet pipes 4 are provided inside the tank body 1, the top end of the air outlet pipe 4 extends to the top side of the inner part of the hollow shaft body 2 and is located below the fan blade 5, and the bottom end of the air outlet pipe 4 extends to the outside of the hollow shaft body 2 and is located on the top side of the inner part of the tank body 1.

[0035] In an optional embodiment: the liquid supply part includes a liquid inlet pipe 14, a mounting top plate 9, a water tank 10 and a second pump body 13, and cold water with a lower temperature is injected into the water tank 10. The bottom end of the liquid inlet pipe 14 extends to the interior of the hollow shaft body 2. The water tank 10 is installed on the mounting top plate 9. A liquid through groove 91 is provided in the mounting top plate 9. The top end of the liquid inlet pipe 14 extends into the liquid through groove 91. The input end of the second pump body 13 is connected to the interior of the water tank 10 through a pipeline, and the output end of the second pump body 13 is connected to the liquid through groove 91 through a pipeline, so that the water in the water tank 10 can be pumped into the interior of the hollow shaft body 2 by starting the second pump body 13.

[0036] In an optional embodiment: the cooling air supply unit includes a refrigeration component 11 and a first pump body 12, the refrigeration component 11 is installed on the water tank 10, the input end of the first pump body 12 is connected to the refrigeration component 11, and the output end of the first pump body 12 is connected to the cooling air main pipe 6 through a pipeline. Specifically, the refrigeration component 11 can be an evaporator, a refrigeration box, etc., which can be a device in the prior art that can produce cooling air.

[0037] In an optional embodiment: a tube-liquid cavity 140 in an annular shape is provided on the liquid inlet pipe 14, and two ends of the tube-liquid cavity 140 respectively pass through the top and bottom ends of the liquid inlet pipe 14, and an annular blocking block 141 is connected to the top of the inner wall of the liquid inlet pipe 14, and a waterproof and breathable membrane layer 15 is also fixedly connected to the inner top side of the hollow shaft body 2, and the top ends of the liquid inlet pipe 14 and the air outlet pipe 4 both pass through and extend to the top of the waterproof and breathable membrane layer 15, and the top sides of the air-conditioning main pipe 6 and the air outlet pipe 4 are both located on the inner side of the liquid inlet pipe 14, and the top end of the air-conditioning main pipe 6 passes through the waterproof and breathable membrane layer 15 and extends to the top of the hollow shaft body 2. Specifically, water flows from the tube-liquid cavity 140 on the liquid inlet pipe 14 to the interior of the hollow shaft body 2, and the inner side of the top end of the liquid inlet pipe 14 can be blocked by the annular blocking block 141, so that the water in the liquid groove 91 can smoothly pass through the tube-liquid cavity 140 and flow into the interior of the hollow shaft body 2. Specifically, the waterproof breathable membrane layer 15 can be a waterproof breathable membrane usually composed of three layers of materials: two layers of PP spunbond non-woven fabrics and a layer of PE polymer breathable membrane, so as to prevent the water inside the hollow shaft body 2 from being introduced into the top side of the hollow shaft body 2. Specifically, the hollow shaft body 2 and the split stirring tube 7 are both made of materials with good thermal conductivity, such as aluminum or copper, to improve the cooling efficiency.

[0038] In an optional embodiment: the rotating part includes a driving motor 3, which is installed on the top of the tank body 1, and the top output shaft of the driving motor 3 is fixedly connected to the first gear 31, the top of the hollow shaft body 2 extends to the top of the tank body 1 and is connected to the second gear 32, the top side and the bottom of the hollow shaft body 2 rotate on the top side and the bottom side of the tank body 1 respectively through bearings, and the bottom end of the hollow shaft body 2 extends to the bottom of the tank body 1, and the bearing can be a sealed bearing to maintain the sealing of the connection between the hollow shaft body 2 and the tank body 1, and the first gear 31 and the second gear 32 are meshed, so that when the driving motor 3 is running, the first gear 31 is driven to rotate, and the second gear 32 connected to the first gear 31 can be driven to rotate, so that the hollow shaft body 2 rotates.

[0039] In an optional embodiment: the top of the tank body 1 is connected to an exhaust pipe 101 connected to the interior of the tank body 1, and exhaust is facilitated by the exhaust pipe 101. The bottom of the tank body 1 is connected to a discharge pipe 103, and a valve is installed on the discharge pipe 103 to facilitate liquid discharge. The tank body 1 is also connected to a ventilation pipe 104 and a feed funnel 102, and the feed funnel 102 facilitates the entry of materials. The ventilation pipe 104 is installed with a pressure relief valve, and the inner wall of the tank body 1 is installed with an air pressure gauge 105. Furthermore, the present application also includes a controller, and the pressure relief valve and the air pressure gauge 105 are electrically connected to the controller, so that the air pressure inside the tank body 1 can be controlled.

[0040] In an optional embodiment: two diversion stirring tubes 7 are provided, wherein the top end surface of one diversion stirring tube 7 is higher than the top end surface of the other diversion stirring tube 7, so as to facilitate the two diversion stirring tubes 7 to mix and stir the materials inside the tank body 1, and a diversion plate 16 inclined downward is connected to the hollow shaft body 2 near the bottom of the top end of the diversion stirring tube 7, and a plurality of diversion holes 161 are provided on the diversion plate 16, so that water can be conveniently introduced into the diversion stirring tube 7 for circulation and diversion through the diversion plate 16, and the water can be diverted into the hollow shaft body 2 through the diversion holes 161 to flow downward.

[0041] A method for producing gluconolactone comprises the following steps:

[0042] Step 1: hydrolyze calcium gluconate in tank 1 to obtain a gluconic acid solution; specifically, first add 500-600 parts of water, then add 100-200 parts of concentrated sulfuric acid, and then add calcium gluconate, keep warm at 50-110°C for 1.5h-2h, and hydrolyze calcium gluconate to obtain a gluconic acid solution.

[0043] Step 2: After the gluconic acid solution is allowed to stand, the calcium sulfate precipitate in the gluconic acid solution is filtered out; specifically, the gluconic acid solution can be allowed to stand for 10 hours to 13 hours, and then the calcium sulfate precipitate in the gluconic acid solution is filtered out.

[0044] Step three, purifying the filtered gluconic acid solution; specifically, adding oxalic acid to the gluconic acid solution after the first filtration, keeping it warm at 50-100°C for 1.5h, filtering the gluconic acid solution again to remove SO42- and Ca2+ in the solution;.

[0045] Step 4, after the gluconic acid solution is concentrated to a concentration of 75%-90%, it is injected into the above-mentioned tank body 1 and stirred to allow crystals to precipitate. Specifically, the gluconic acid solution is further purified by ion exchange resin, and then a low-level ketone non-solvent is added, slowly stirred and cooled to allow crystals to precipitate, and then the remaining solution and crystals are separated, and the crystals are washed and dried to obtain the finished product.

[0046] Specifically, during the stirring and cooling process in the tank body 1, the hollow shaft body 2 is driven to rotate by operating the rotating part, and the first pump body 12 and the second pump body 13 are operated at the same time. The driving of the hollow shaft body 2 allows the multiple branch stirring tubes 7 to drive the materials inside to stir. The cold water liquid in the water tank 10 can be drawn through the second pump body 13 and circulated into the inside of the hollow shaft body 2 and the branch stirring tube 7, so that the hollow shaft body 2 and the branch stirring tube 7 can absorb the heat in the material while stirring the material to cool the material; by operating the first pump body 12, the cold air in the refrigeration part 11 is transported to the cold air main pipe 6 and the cold air branch pipe 8, and the cold air main pipe 6 and the cold air branch pipe 8 are cold-treated by the cold water liquid flowing into the hollow shaft body 2 and the branch stirring tube 7, which makes the circulating water liquid maintain a continuous low temperature effect, thereby effectively cooling the material in the tank body 1;

[0047] When the hollow shaft body 2 is rotated, the fan blades 5 will be driven to rotate synchronously to generate negative pressure above the inside of the tank body 1. On the one hand, the hot air inside the tank body 1 can be discharged to the outside, and the heat on the surface of the hollow shaft body 2 and the diversion stirring tube 7 can be taken away to maintain the low temperature effect of the hollow shaft body 2 and the diversion stirring tube 7; on the other hand, due to the high temperature of the material inside the tank body 1, during the cooling process of the water circulation in the hollow shaft body 2 and the diversion stirring tube 7, water vapor may be generated by the water in the hollow shaft body 2 and the diversion stirring tube 7, and the water vapor will be drawn out to the outer end of the exhaust pipe 4 by the negative pressure, and then discharged to the outside of the tank body 1 through the exhaust pipe 101, so as to prevent the hot water vapor from affecting the cooling effect of the hollow shaft body 2 and the diversion stirring tube 7 during cooling.

[0048] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A production device for gluconolactone, comprising a tank body (1), wherein a hollow shaft body (2) is provided inside the tank body (1), the bottom end of the hollow shaft body (2) extends to the lower part of the tank body (1), and a rotating part for driving the hollow shaft body (2) to rotate is provided on the tank body (1), and a plurality of split flow stirring tubes (7) are connected to the hollow shaft body (2), characterized in that: A cold air main pipe (6) is provided inside the hollow shaft body (2), a cold air branch pipe (8) is provided inside the diversion stirring pipe (7), and both ends of the cold air branch pipe (8) are connected to the cold air main pipe (6). A liquid supply part and a cold air supply part are provided above the tank body (1), the liquid supply part is used to circulate water into the hollow shaft body (2), and the cold air supply part is used to circulate cold air into the cold air main pipe (6).

2. A production device for gluconolactone according to claim 1, characterized in that: The hollow shaft (2) is located at the upper part of the tank body (1) and is connected to a fan blade (5). When the hollow shaft (2) is rotated, the fan blade (5) rotates synchronously to generate negative pressure above the inside of the tank body (1), so that the gas inside the tank body (1) is drawn out to the outside of the tank body (1); A plurality of air outlet pipes (4) are provided inside the tank body (1), the top ends of the air outlet pipes (4) extend to the top side of the inside of the hollow shaft body (2) and are located below the fan blades (5), and the bottom ends of the air outlet pipes (4) extend to the outside of the hollow shaft body (2) and are located on the top side inside the tank body (1).

3. A production device for gluconolactone according to claim 2, characterized in that: The liquid supply part comprises a liquid inlet pipe (14), a mounting top plate (9), a water tank (10) and a second pump body (13); the bottom end of the liquid inlet pipe (14) extends to the interior of the hollow shaft body (2); the water tank (10) is mounted on the mounting top plate (9); a liquid passage groove (91) is provided in the mounting top plate (9); the top end of the liquid inlet pipe (14) extends into the liquid passage groove (91); the input end of the second pump body (13) is connected to the interior of the water tank (10) through a pipeline; and the output end of the second pump body (13) is connected to the liquid passage groove (91) through a pipeline.

4. A production device for gluconolactone according to claim 3, characterized in that: The cold air supply unit comprises a refrigeration component (11) and a first pump body (12); the refrigeration component (11) is installed on a water tank (10); an input end of the first pump body (12) is connected to the refrigeration component (11); and an output end of the first pump body (12) is connected to a cold air main pipe (6) via a pipeline.

5. A production device for gluconolactone according to claim 4, characterized in that: The liquid inlet pipe (14) is provided with a tube-liquid cavity (140) arranged in an annular shape, and the two ends of the tube-liquid cavity (140) respectively penetrate the top end and the bottom end of the liquid inlet pipe (14), and the top end of the inner wall of the liquid inlet pipe (14) is connected to an annular block (141). The inner top side of the hollow shaft body (2) is also fixedly connected to a waterproof and breathable membrane layer (15). The top ends of the liquid inlet pipe (14) and the air outlet pipe (4) both pass through and extend to the top of the waterproof and breathable membrane layer (15). The top sides of the cold air main pipe (6) and the air outlet pipe (4) are both located on the inner side of the liquid inlet pipe (14), and the top end of the cold air main pipe (6) passes through the waterproof and breathable membrane layer (15) and extends to the top of the hollow shaft body (2).

6. A production device for gluconolactone according to claim 5, characterized in that: The rotating part comprises a driving motor (3), the driving motor (3) is mounted on the top of the tank body (1), the top output shaft of the driving motor (3) is fixedly connected to a first gear (31), the top end of the hollow shaft body (2) extends to the top of the tank body (1) and is connected to a second gear (32), the top side and the bottom of the hollow shaft body (2) are respectively rotated on the top side and the bottom side of the tank body (1) through bearings, the bottom end of the hollow shaft body (2) extends to the bottom of the tank body (1), and the first gear (31) and the second gear (32) are meshed.

7. A production device for gluconolactone according to claim 6, characterized in that: The top of the tank body (1) is connected to an exhaust pipe (101) which is in communication with the interior of the tank body (1), the bottom of the tank body (1) is connected to a discharge pipe (103), the tank body (1) is also connected to a vent pipe (104) and a feed hopper (102), a pressure relief valve is installed on the vent pipe (104), and an air pressure measuring gauge (105) is installed on the inner wall of the tank body (1).

8. A production device for gluconolactone according to claim 1, characterized in that: The diverter stirring tubes (7) are provided in two forms, wherein the top end surface of one of the diverter stirring tubes (7) is higher than the top end surface of the other diverter stirring tube (7), and a diverter plate (16) inclined downward is connected to the hollow shaft body (2) near the bottom of the top end of the diverter stirring tube (7), and a plurality of diverter holes (161) are provided on the diverter plate (16).

9. A method for producing gluconolactone, characterized in that: The following steps are involved: Step 1, hydrolyzing calcium gluconate in a tank (1) to obtain a gluconic acid solution; Step 3, purifying the filtered gluconic acid solution; Step 4, after concentrating the gluconic acid solution, inject it into the tank (1) of any one of claims 1-8 and stir it to allow crystals to precipitate.

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