Concentrating type condensation digestion device

Abstract

The invention discloses a gathering type condensation digestion device which comprises a machine body, a reaction container and a condensation atomization system, a reagent is introduced into the reaction container, inert gas is introduced into the reaction container for pre-pressurization, and the condensation atomization system is connected with the reaction container and arranged above the reaction container. The gathering type condensation digestion device has condensation, reflux and atomization functions, can be applied to digestion treatment of solid powder or liquid, organic, inorganic and biological samples, converts organic or inorganic substances in the samples into a form capable of being dissolved in a solvent, provides high-quality samples for subsequent analysis, and has the advantages of simplicity in operation, convenience in operation and high practicability. The method has the characteristics of large sample treatment range, complete digestion, no loss and the like.

Description

Technical Field

[0001] The invention relates to the technical field of digestion, and in particular to a concentrated microwave digestion device with condensation reflux atomization functions. Background Art

[0002] Microwave is an electromagnetic wave with a frequency in the range of 300MHz to 300000MHz, that is, an electromagnetic wave with a wavelength in the range of 100cm to 0.1cm, also known as ultra-high frequency, located between infrared radiation and radio waves in the electromagnetic spectrum. It has been widely used in food, textiles, plastics, geology, metallurgy, coal, biomedicine, petrochemicals, environmental monitoring, sewage treatment, battery manufacturing, cosmetics and other fields. The microwave frequencies used in industry mainly include 915±25MHz, 2450±13MHz, 5800±75MHz, 22125±125MHz, etc. Among them, the most widely used frequency is 2450±13MHz, and the output power is 600W~800W. It can release about 200KJ of energy in just a few minutes, causing the molecules of the medium to vibrate about 2.45 billion times per second. The friction between the molecules of the medium causes the temperature of the medium to rise, so that the inside and outside of the medium material are heated up almost at the same time, forming a body heat source state, which greatly shortens the heat conduction time in conventional heating. When the condition is that the dielectric loss factor is negatively correlated with the medium temperature, the material is heated evenly inside and outside.

[0003] At present, the widely used microwave digestion instruments mainly utilize the heating advantages and characteristics of microwaves. Through high temperature and high pressure conditions, they use acid or alkali to ionize samples. Through redox reactions, molecular bonds are destroyed so that samples can be quantitatively detected by atomic absorption and ICP and other equipment. They are mainly used in environmental monitoring, food testing, medicine, petrochemicals, mining geology and other fields.

[0004] Usually, the sample to be digested in a special plastic digestion tank is added with acid to form a strong polar solution. The microwave body heating properties are used to heat the solution inside and outside at the same time, which is faster and more uniform, and improves efficiency. Microwave digestion is generally carried out in a closed digestion tank. The pressure system can produce overheating, heating to a temperature higher than the boiling point under normal pressure, greatly improving the digestion speed, and can digest samples that cannot be digested by general wet digestion. Microwave digestion in a closed system can prevent the loss of volatile elements and carry out some projects that cannot be carried out by conventional wet digestion. However, the amount of samples processed by traditional closed microwave digestion devices is relatively limited, and the maintenance amount of organic samples is usually not more than 0.5g, and the non-polar samples are not more than 1.0g. Traditional ultra-high pressure digestion reaction tanks have large batch processing capacity and are suitable for large-scale sample processing. The furnace cavity is strong and not easy to deform; but they consume a lot of energy, are bulky, have a high price, high use and maintenance costs, and have a low safety factor.

[0005] In addition, due to the uneven distribution of microwave fields in common microwave digestion chambers, the samples in the chamber are prone to receiving microwaves unevenly, which affects the digestion effect. The usual solution is to rotate the plate so that each sample receives microwaves as evenly as possible. However, the temperature and pressure changes of the samples before and after heating are relatively large during the cycle, and the turntable design cannot fix the digestion tank. From a safety perspective, there are certain shortcomings.

[0006] At present, microwaves are divided into pulse microwaves and non-pulse microwaves according to the power emission mode. The traditional fixed power output is characterized by switch-type pulse microwaves. This control mode is not only difficult to control, but may also directly affect the digestion effect. The current microwave development direction is automatic power frequency conversion control and non-pulse technology, which is characterized by automatic power change and non-pulse microwave output. The advantage is that there is no need to turn off microwave emission. Under the condition of continuous microwave emission, the microwave power output is automatically and linearly changed according to the temperature and pressure feedback signal, the reaction state is adjusted, and the temperature control is more accurate, ensuring the safety and smooth progress of the experiment.

[0007] Chinese patent CN2748147Y discloses an ultrasonic microwave digestion and extraction device, including: a box, a magnetron, a waveguide, a sample bottle, a microwave power supply, a reflux condenser, a condenser sleeve, an electronic control system, the electronic control system is composed of a microcontroller, the box is a hexahedron made of metal plates, a door that can be opened and closed by a hinge is installed on the front of the box, a microwave radiation cavity is formed by a metal partition in the box, the sample bottle is placed in the microwave radiation cavity, one end of the reflux condenser is inserted into the mouth of the sample bottle through a sleeve fixed to the top of the box by a nut, and is fixed to the top of the box by a positioning ring. This technology installs ultrasound and microwaves on the device box, and the box structure is a conventional hexahedron. The ordinary box structure and conventional microwave function may result in incomplete digestion of large mass samples; in addition, this technology has a reflux condenser, but volatile elements are easily retained in the reflux tube wall, and the residue cannot be effectively refluxed by cooling alone.

[0008] Chinese patent CN205301023U discloses a normal pressure sealed pollution-free digester, which consists of a ground-mouth triangular flask, a vertical condenser, a solution backflow prevention bottle, a toxic gas absorption bottle and a porous plate, characterized in that the ground-mouth triangular flask is connected to a vertical condenser, the upper side of the vertical condenser is connected to the solution backflow prevention bottle through an air guide tube, the solution backflow prevention bottle is connected to the toxic gas absorption bottle through an air guide tube, the outlet of the air guide tube is blocked by a porous plate and extends downward to the bottom of the toxic gas absorption bottle, a certain amount of toxic gas absorption liquid is added to the toxic gas absorption bottle, and the absorption liquid isolates the sample solution to be digested from the ambient air. This technology only provides a device for digestion by conventional bottom heating condensation, and conventional sealed heating digestion is difficult to meet the digestion of oxide samples with large mass and a large amount of metal elements.

[0009] The sampling quality of solid samples processed by existing microwave digestion instruments is usually limited, mainly due to the constraints of digestion container size, digestion chamber design, etc. Therefore, when analyzing trace and ultra-trace elements in solid samples, existing microwave digestion instruments are difficult to meet the measurement requirements. Therefore, it is worthwhile to further study and develop the design of microwave digestion instruments that use large-volume digestion containers and multiple symmetrical inner surface digestion chambers to achieve efficient digestion. Summary of the invention

[0010] The object of the present invention is to provide a concentrated condensation digestion device, which has a condensation reflux atomization function and can be applied to the digestion treatment of solid powder or liquid, organic, inorganic, and biological samples, converting the organic or inorganic matter in the sample into a form soluble in a solvent, providing high-quality samples for subsequent analysis, and has the characteristics of a large range of sample processing, complete digestion, and no loss.

[0011] To achieve the above-mentioned purpose, the present invention provides a concentrated condensation digestion device, which comprises: a body, a reaction container, and a condensation atomization system, wherein a reagent is introduced into the reaction container, and an inert gas is introduced for pre-pressurization, and the condensation atomization system is connected to the reaction container and placed above the reaction container;

[0012] The machine body comprises a chamber, a machine door, a machine cover, a control system, a microwave generating system, and a base. The chamber is located inside the machine body and is opened or closed by the machine door. The machine cover is located on the top of the machine body. The control system is located on the top surface or one side surface of the machine body. The microwave generating system is connected to the chamber. The base is not a turntable type, but a bottom plate fixed to the bottom surface of the chamber. The reaction container is placed on the base of the chamber.

[0013] The condensation atomization system comprises a reflux tank, an atomization generator, an external interface, a condenser, a circulating inner tube, a circulating outer tube, a condenser inner circulation water inlet, a condenser inner circulation water outlet, a condenser outer circulation water inlet, a condenser outer circulation water outlet, and a safety cap valve, wherein the safety cap valve is located at the top of the condensation atomization system, the lower end of the condenser is connected to the reflux tank, the side end of the reflux tank is connected to the atomization generator, the upper part of the reflux tank is provided with an external interface connected to an external gas; the bottom of the condenser is provided with a condenser lower outlet, and the condenser lower outlet is connected to the reaction vessel;

[0014] The atomizer generator is a glass concentric atomizer, the center of which is a capillary tube, the capillary tube is parallel to the airflow of the carrier gas, the carrier gas is introduced through an external air inlet instrument port on one side of the body, the airflow quickly passes through the end of the capillary tube, meets the carrier liquid in the atomizer generator at the atomizer nozzle and shears the liquid to form tiny droplets, the tiny droplets are sprayed out with the carrier gas, condensed through the condenser tube to form condensate, the condensate droplets flow back into the reflux pool, and then flow into the reaction container.

[0015] Furthermore, the chamber structure is a polyhedron, the left and right sides and the front and back sides are respectively or all symmetrical, or the diagonal sides are symmetrical, and the upper and lower sides are symmetrical, and it is composed of at least 8 inner surfaces to achieve the concentrated radiation of microwaves in the cavity; the chamber is a closed rectangular industrial resonant cavity; the material of the chamber is all stainless steel or polytetrafluoroethylene, and is provided with a multi-layer anti-corrosion coating; the chamber is also provided with an exhaust system and a cooling system, and the exhaust volume in the chamber is not less than 1.0m 3 The chamber may also be equipped with an air cooling function to continuously cool the reaction container and display the temperature and pressure in real time.

[0016] Furthermore, the machine door is equipped with double or triple independent interlocking sensing equipment, the power is cut off when the machine door is opened, and the microwave generating system cannot work when the machine door is not closed; an observation window is also provided on the machine door, and a heat dissipation net is provided on the outside of the machine body, and the mesh size of the metal grid or wire mesh in the observation window and the heat dissipation net is 0.02 to 0.2 mm.

[0017] Furthermore, the body can be designed to have one or more modes, and the reaction conditions of each mode can be controlled by a program.

[0018] Furthermore, the shape of the reaction container is selected from spherical, cylindrical, cubic, and polyhedral.

[0019] Furthermore, the material of the reaction container is one of tertiary tetrafluoroethylene (PTFE), perfluoroalkoxy (PFA), modified polytetrafluoroethylene (TFM) and quartz. These materials are permeable and propagable to microwaves, so these materials will not absorb microwave energy or absorb very little microwaves, and the ability of the sample inside the reaction container to absorb microwaves is enhanced by penetration.

[0020] Furthermore, the outer wall of the reaction container is a waveguide layer, which is conducive to the penetration of microwaves and good temperature conduction. Its material should be a non-polar molecular substance. Due to the accelerated frequency change of microwaves, the molecules will tend to collide and rub against each other, and the reaction will be violent. In order to improve the safety of operation, a material with small deformation under high temperature and high pressure, small permeability, good recovery under high temperature and heavy pressure, and high surface finish can be selected. For example, polyetheretherketone (PEEK) is a special engineering plastic with excellent properties such as high temperature resistance, self-lubrication, easy processing and high mechanical strength. The waveguide layer uses PEEK fiber, which contains more than 10% carbon fiber or more than 10% glass fiber, but is not limited to this. It can also be other new materials with high temperature resistance and high mechanical strength, but is not limited to this.

[0021] Furthermore, there is a spring piece in the safety cap valve. When the pressure in the reaction container exceeds the tolerable pressure, the safety cap valve automatically opens to balance the pressure. The spring piece is compressed by a ceramic material.

[0022] Furthermore, the volume of the reaction container is 100 mL to 2000 mL; the temperature inside the reaction container is 0 to 350° C., and at the highest temperature, the internal pressure can reach 10.0 MPa.

[0023] Furthermore, the reagent is an acid, an alkali or other reagent required for digestion, the acid is at least one of hydrochloric acid, nitric acid, phosphoric acid, hydrofluoric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, perchloric acid, boric acid, oxalic acid, tartaric acid, and citric acid; the alkali is at least one of ammonia water and sodium hydroxide, and the other reagent required for digestion is hydrogen peroxide.

[0024] Furthermore, there are two external gas inlet ports, which are used to introduce different gases for switching between the external gas of the reaction container and the carrier gas of the atomizer generator. The external gas of the reaction container is an inert gas, which is selected from at least one of nitrogen, helium and argon, with a flow rate of 0.5 to 3.0 L / min and a pressure of 0.5 to 8.0 MPa; the carrier gas of the atomizer generator is an inert gas, which is at least one of nitrogen, helium and argon, with a flow rate of 0.05 to 1.5 L / min and a pressure of 0.1 to 1.0 MPa; the carrier liquid in the atomizer generator is a dilute acid solution, which is hydrochloric acid and / or nitric acid, with a mass concentration of 0.5 to 5.0%, and a flow rate of 0.1 to 2.5 mL / min.

[0025] Furthermore, a temperature sensor probe and a pressure sensor probe are provided in the chamber, the temperature in the chamber is 0-350°C, the temperature control accuracy is ±0.05°C, the pressure in the chamber is 0-10.0MPa, and the pressure control accuracy is 0.01MPa; a pipeline is provided in the chamber to connect the reaction container with the outside world.

[0026] Furthermore, the control system includes a control panel and a display screen, and the display screen is designed as a touch screen; the control system adopts a high-precision temperature and pressure control system. The operator can observe the data and curves of temperature and pressure changes through the control panel to understand the operation of the machine, monitor temperature and pressure abnormalities in real time to ensure safety, the pressure control range is: 0~10.0MPa, the pressure control accuracy is: 0.01MPa, overpressure can be automatically adjusted and microwave emission can be stopped, and automatic alarm can be given.

[0027] Furthermore, internal components are provided between the chamber and the body, and the internal components are a magnetron, a waveguide tube, a diode, a refrigerator, a transformer, and a fan. The magnetron is connected to the waveguide tube, and the waveguide tube is provided between the magnetron and the chamber.

[0028] Furthermore, the refrigerator is a semiconductor refrigerator, which is used to cool the chamber, has an operating temperature of 0°C to 25°C, and a control temperature of 15°C to 20°C.

[0029] Furthermore, the microwave frequency of the microwave generating system is 2450MHz, and the microwave output power is 0-1600W, which is automatically and continuously adjustable; the microwaves of the microwave generating system are non-pulse continuous automatic power frequency conversion type, the power changes automatically, the output is non-pulse microwaves, the service life is long, and the emitted electromagnetic waves have good uniformity.

[0030] Furthermore, the reaction container is connected to the lower outlet of the condenser through a fixing ring, and the fixing ring is composed of an outer interlayer, an inner interlayer, a first clip, a second clip, a third clip, a fourth clip, a first screw, a second screw, a third screw, and a fourth screw; the first clip and the second clip are fixed by the first screw and the second screw; the third clip and the fourth clip are fixed by the third screw and the fourth screw.

[0031] The concentrated condensation digestion device of the present invention directly acts on the sample by focusing microwaves, performs efficient radiation, digests the sample under micro-pressure and low pressure, and is safe to operate. The microwave focusing effect can speed up the reaction speed, reduce the amount of reagents used, and improve the efficiency of the reaction. The chamber volume of the concentrated condensation digestion device of the present invention is large, and a large amount of samples can be processed at one time, which can improve the problem that the existing digestion device processes a small amount of samples and is difficult to enrich low-content samples. The high temperature and high pressure generated in the traditional microwave closed digestion reaction will cause many elements and compounds to be in a gaseous state. If the sealing effect is not good, it will cause serious element loss, affecting the consistency of sample digestion. The present invention solves the problem of volatile element loss through the design of condensation atomization reflux. The volatile residual phase attached to the wall of the condensation tube is dissolved by the tiny droplets sprayed by the atomization generator, condensed by the condensation tube, and the condensed droplets flow back into the reflux tank and into the reactor. At the same time, the present invention does not need to adopt a turntable type, and the fixed chassis design is stable and safe.

[0032] The clustered condensation digestion device of the present invention adopts a self-locking buffer cavity door. When the reaction is abnormal, the buffer structure ensures the personal safety of the operator and the integrity of the furnace door structure. The cavity door and the cavity are tightly combined without microwave leakage. The clustered condensation digestion device of the present invention adopts a temperature and pressure dual control system to control the internal pressure and temperature, and displays them in real time. When the pressure in the reaction vessel exceeds the set protection value, the microwave will automatically stop heating. The safety cap valve has a double insurance function. When the pressure in the reaction vessel exceeds the pressure that can be tolerated, the safety cap valve automatically opens and the gas is discharged to prevent damage to the reaction vessel and instantaneous harm to the human body. A high-precision temperature and pressure control system is adopted, and the operator understands the operation of the machine by observing the data and curves of temperature and pressure changes. Its software module can actively stop running when the slope is out of control, greatly reducing the possibility of tank explosion. It has real-time temperature and pressure abnormal monitoring. When the high-precision temperature and pressure control system fails, the system will sense and stop running in time as a backup measure to ensure safety.

[0033] The concentrated condensation digestion device of the present invention mainly includes a body, a reaction container, and a condensation atomization system. Before the reaction, the sample is added to the reaction container, the reaction container is placed in the chamber, fixed, connected to the condensation atomization system, and the condensation atomization system is turned on at the same time. The acid, alkali or specific reagent required for the digestion reaction is introduced through the inlet of the condensation atomization system, and the safety cap valve of the reagent addition port is closed. When the sample is digested, especially the digestion of organic samples, there may be an instantaneous reaction that violently releases a large amount of heat. The condensation atomization system should be turned on in advance before the digestion reagent is introduced to maintain condensation reflux atomization to prevent instantaneous volatilization and avoid element loss. Open the control panel, set the reaction temperature, time and pressure. After the parameters are set, start the program, the digestion device starts working, turn on the carrier gas and introduce the carrier liquid at the same time, the atomizer starts working, and the liquid remaining on the wall of the device during the reaction is atomized into extremely fine droplets by the atomizer. The surface area of ​​the liquid can be increased by 10,000 times. The atomizer generator also cooperates with the flow of carrier gas. A vortex effect will be generated at the moment of spraying, which has a mixing effect on the inside, accelerates mass transfer, keeps the droplets moving, and returns to the reaction vessel under the action of condensation.

[0034] The concentrated condensation digestion device of the present invention realizes the direct action of microwaves on the sample by concentrating the microwaves through the design of 8 or more symmetrical inner surfaces in the chamber, thereby obtaining efficient radiation, shortening the reaction time and achieving complete digestion.

[0035] The concentrated condensation digestion device of the present invention digests a large amount of sample through the design of a large-volume digestion reaction container, is suitable for the digestion of low-content samples, and greatly reduces the detection limit of the sample.

[0036] The concentrated condensation digestion device of the present invention operates under micro-pressure or low pressure, which improves the safety of the digestion reaction and effectively avoids the potential safety hazards brought by high-pressure reactions to the digestion process.

[0037] The concentrated condensation digestion device of the present invention can prevent the volatilization of acid gas and elements during the digestion process and the loss of liquid remaining on the wall of the device by controlling the condenser and the atomization generator installed in the condensation atomization system, thereby obtaining effective condensation reflux. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The present invention will be further described below in conjunction with the accompanying drawings:

[0039] Figure 1 This is a front view of the external structure of the concentrated condensation digestion device of the present invention;

[0040] Figure 2 is a cross-sectional view of the internal structure of the chamber of the present invention;

[0041] Figure 3 It is a structural schematic diagram of the condensation atomization system of the present invention;

[0042] Figure 4 It is a structural schematic diagram of the atomizing generator of the present invention;

[0043] Figure 5 is a schematic diagram of a safety cap valve of a reaction vessel of the present invention;

[0044] Figure 6 is a schematic diagram of a fixing ring of a reaction vessel of the present invention;

[0045] Figure 7 It is a schematic diagram of the installation of internal components between the chamber and the body.

[0046] Explanation of reference numerals: 1. machine body; 2. machine cover; 3. machine door; 4. connection port; 5. display screen; 6. control panel; 7. upper lock buckle; 8. lower lock buckle; 9. exhaust port; 10. first external air inlet port; 11. second external air inlet port; 12. heat dissipation net; 13. reactor sealing ring; 14. reaction vessel; 15. fixing ring; 16. screw; 17. outer wall of reaction vessel; 18. inner wall of reaction vessel; 19. base; 20. temperature sensor probe; 21. pressure sensor probe; 22. cavity layer; 23. chamber; 24. condenser external circulation water inlet; 25. condenser internal circulation water inlet; 26. safety cap valve; 27. condenser internal circulation water outlet; 28. condenser tube; 29. ​​circulation inner tube; 30 , circulation outer pipe; 31, condenser outer circulation water outlet; 32, external interface; 33, reflux tank; 34, reflux tank outlet; 35, condenser lower outlet; 36, sealing ring; 37, atomizer; 38, carrier liquid inlet; 39, carrier gas inlet; 40, atomizer nozzle; 41, capillary; 42, safety cap valve cover; 43, spring; 44, safety cap valve core; 45, first clip; 46, second clip; 47, outer interlayer; 48, inner interlayer; 49, third clip; 50, fourth clip; 51, first screw; 52, second screw; 53, third screw; 54, fourth screw; 55, 58, 61, magnetron; 56, 59, 62, diode; 57, refrigerator; 60, transformer; 63, fan. DETAILED DESCRIPTION

[0047] Please also refer to Figure 1 and Figure 2The concentrated condensation digestion device of the present invention comprises: a machine body 1, a reaction vessel 14, and a condensation atomization system. Reagents are introduced into the reaction vessel 14, and inert gas is introduced for pre-pressurization. The condensation atomization system is connected to the reaction vessel 14 and is placed above the reaction vessel 14; the machine body 1 comprises a chamber 23, a machine door 3, a machine cover 2, a control system, a microwave generating system, and a base 19. The chamber 23 is located inside the machine body 1 and is opened or closed by the machine door 3. The machine cover 2 is located on the top of the machine body 1. The control system is located on the top surface or one side surface of the machine body 1. The microwave generating system is connected to the chamber 23. The base 19 is not a turntable type, but a chassis fixed to the bottom surface of the chamber 23; the reaction vessel 14 is placed on the base 19 of the chamber 23.

[0048] Please refer to Figure 3 and Figure 4 The condensation atomization system includes a reflux pool 33, an atomization generator 37, an external interface 32, a condenser 28, a circulating inner tube 29, a circulating outer tube 30, a condenser inner circulation water inlet 25, a condenser inner circulation water outlet 27, a condenser outer circulation water inlet 24, a condenser outer circulation water outlet 31, and a safety cap valve 26. The safety cap valve 26 is located at the top of the condensation atomization system. The lower end of the condenser 28 is connected to the reflux pool 33, and the side end of the reflux pool 33 is connected to the atomization generator 37. The upper part of the reflux pool 33 is provided with an external interface 32, which is connected to the external gas through the first external gas inlet instrument port 10; a condenser lower outlet 35 is provided at the bottom of the condenser, and the condenser lower outlet 35 is connected to the reaction container 14.

[0049] Furthermore, the atomizer 37 is a glass concentric atomizer, the center of which is a capillary 41. The capillary 41 is parallel to the airflow of the carrier gas. The carrier gas is introduced through an external air inlet port on one side of the body 1. The airflow quickly passes through the end of the capillary 41, meets the carrier liquid in the atomizer generator 37 at the atomizer nozzle 40 and shears the liquid to form tiny droplets. The tiny droplets are sprayed out with the carrier gas, condensed through the condenser 28 to form condensate, and the condensate droplets flow back into the reflux pool 33 and into the reaction vessel 14.

[0050] Furthermore, the structure of chamber 23 is a polyhedron, with left and right sides and front and back being symmetrical surfaces, or diagonal surfaces being symmetrical, and upper and lower surfaces being symmetrical surfaces, and consisting of at least 8 inner surfaces to achieve concentrated radiation of microwaves in the cavity. Chamber 23 is a closed rectangular industrial resonant cavity. The volume of chamber 23 needs to be specifically designed according to the volume of the reaction vessel. It is made of all stainless steel or polytetrafluoroethylene and is provided with a multi-layer anti-corrosion coating; polytetrafluoroethylene is resistant to corrosion by acids, alkalis, organic solvents, etc. Chamber 23 is also provided with an exhaust system and a cooling system. The exhaust volume of chamber 23 is not less than 1.0m 3 The chamber 23 may also be equipped with an air cooling function to continuously cool the reaction vessel 14 and display the temperature and pressure in real time.

[0051] Furthermore, the door 3 is equipped with double or triple independent interlocking sensing equipment, the power is cut off when the door 3 is opened, and the microwave generating system cannot work when the door 3 is not closed. An observation window is provided on the door 3, and a heat dissipation net is provided on the side of the body 3. The mesh of the metal grid or wire mesh in the observation window and the heat dissipation net is 0.02-0.2 mm, which effectively prevents microwave leakage.

[0052] Furthermore, the body 1 can be designed as one or more modes, not limited to Figure 2 The model shown, and the reaction conditions of each model can be controlled by program.

[0053] Furthermore, the shape of the reaction container 14 is selected from a spherical shape, a cylindrical shape, a cubic shape, and a polyhedron shape.

[0054] Furthermore, the material of the reaction container 14 is one of tertiary polytetrafluoroethylene (PTFE), perfluoroalkoxyethylene (PFA), modified polytetrafluoroethylene (TFM) and quartz. These materials are permeable and propagable to microwaves, so these materials will not absorb microwave energy or absorb very little microwaves, and through penetration, the ability of the sample inside the reaction container 14 to absorb microwaves is enhanced.

[0055] Furthermore, the outer wall 17 of the reaction container is a waveguide layer, which is helpful for the penetration of microwaves and good temperature conduction. Its material should be a non-polar molecular substance. Due to the accelerated frequency change of microwaves, the molecules will tend to collide and rub against each other, and the reaction will be violent. In order to improve the safety of operation, a material with small deformation under high temperature and high pressure, small permeability, good recovery under high temperature and heavy pressure, and high surface finish can be selected. For example, polyetheretherketone (PEEK) is a special engineering plastic with excellent properties such as high temperature resistance, self-lubrication, easy processing and high mechanical strength. The waveguide layer uses PEEK fiber, which contains more than 10% carbon fiber or more than 10% glass fiber, but is not limited to this. It can also be other new materials with high temperature resistance and high mechanical strength, but is not limited to this.

[0056] Please refer to Figure 5 Furthermore, there is a spring piece 43 in the safety cap valve 26. When the pressure in the reaction container 14 exceeds the tolerable pressure, the safety cap valve 26 automatically opens to balance the pressure. The spring piece 43 is pressed tightly with a ceramic material.

[0057] Furthermore, the volume of the reaction container 14 is 100 mL to 2000 mL. The temperature in the reaction container 14 is 0 to 350° C., and at the highest temperature, the internal pressure can reach 10.0 MPa.

[0058] Furthermore, the reagent is an acid, an alkali or other reagent required for digestion, the acid is at least one of hydrochloric acid, nitric acid, phosphoric acid, hydrofluoric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, perchloric acid, boric acid, oxalic acid, tartaric acid, and citric acid; the alkali is at least one of ammonia water and sodium hydroxide, and the other reagent required for digestion is hydrogen peroxide.

[0059] Furthermore, the number of external gas inlet instrument ports of the body 1 is two, namely a first external gas inlet instrument port 10 and a second external gas inlet instrument port 11. The external gas inlet instrument ports are used to introduce different gases for switching between the external gas of the reaction container 14 and the carrier gas of the atomizer generator 37. The external gas of the reaction container 14 is an inert gas, which is selected from at least one of nitrogen, helium and argon, with a flow rate of 0.5 to 3.0 L / min and a pressure of 0.5 to 8.0 MPa; the carrier gas of the atomizer generator 37 is an inert gas, which is at least one of nitrogen, helium and argon, with a flow rate of 0.05 to 1.5 L / min and a pressure of 0.1 to 1.0 MPa; the carrier liquid in the atomizer generator 37 is a dilute acid solution, which is hydrochloric acid and / or nitric acid, with a mass concentration of hydrochloric acid and / or nitric acid of 0.5 to 5.0%, and a flow rate of the carrier liquid of 0.1 to 2.5 mL / min.

[0060] Furthermore, a temperature sensor probe 20 and a pressure sensor probe 21 are provided in the chamber 23. The chamber 23 adopts wireless temperature and pressure control, and the inner surface of the chamber 23 is provided with a corrosion-resistant layer, which will not be interfered by the microwave field, has high measurement accuracy and good safety. The temperature in the chamber 23 is 0-350°C, the temperature control accuracy is ±0.05°C, the pressure in the chamber 23 is 0-10.0MPa, and the pressure control accuracy is 0.01MPa; a pipeline is provided in the chamber 23 to connect the reaction vessel 14 with the outside world.

[0061] Furthermore, the control system includes a control panel 6 and a display screen 5, and the display screen 5 is designed as a touch screen; the control system adopts a high-precision temperature and pressure control system. The operator can observe the data and curves of temperature and pressure changes through the control panel to understand the operation of the machine, monitor temperature and pressure abnormalities in real time to ensure safety, the pressure control range is: 0~10.0MPa, the pressure control accuracy is: 0.01MPa, overpressure can be automatically adjusted and microwave emission can be stopped, and an automatic alarm can be given.

[0062] Please refer to Figure 7 Furthermore, internal components are provided between the chamber 23 and the body 1, and the internal components are magnetrons 55, 58, 61, waveguides, diodes 56, 59, 62, a refrigerator 57, a transformer 60, and a fan 63. The magnetron 55 is connected to the waveguide, and the waveguide is provided between the magnetron 55 and the chamber 23.

[0063] Furthermore, the refrigerator 57 is a semiconductor refrigerator for cooling the interior of the chamber, with an operating temperature of 0°C to 25°C and a control temperature of 15°C to 20°C.

[0064] Furthermore, the microwave frequency of the microwave source of the microwave generating system is 2450MHz, and the microwave output power is 0-1600W, which is automatically and continuously adjustable; the microwave of the microwave generating system is a non-pulse continuous automatic power frequency conversion type, the power changes automatically, the output is a non-pulse microwave, the service life is long, and the uniformity of the emitted electromagnetic waves is good.

[0065] Please refer to Figure 6 Further, the reaction vessel 14 is connected to the lower outlet 35 of the condenser through a fixing ring 15, and the fixing ring 15 is composed of an outer interlayer 47, an inner interlayer 48, a first clip 45, a second clip 46, a third clip 49, a fourth clip 50, a first screw 51, a second screw 52, ​​a third screw 53, and a fourth screw 54; the first clip 45 and the second clip 46 are fixed by the first screw 51 and the second screw 52; the third clip 49 and the fourth clip 50 are fixed by the third screw 53 and the fourth screw 54.

[0066] The operation of the entire digestion device is controlled by the control panel 6, and the display screen 5 displays all programs in real time. When the device is started, the machine door 3 and the machine cover 2 are automatically locked and cannot be opened manually; the transformer 60 supplies the diodes (56, 59, 62) with work, and the diodes are connected to the magnetrons (55, 58, 61), and microwaves are sent into the chamber 23 through the cavity layer 22, forming microwave concentration in the chamber 23, and the microwave concentration acts on the reaction container 14; the temperature sensor probe 20 and the pressure sensor probe 21 in the chamber 23 monitor the changes in temperature and pressure in the chamber 23 in real time, and the safety cap valve 26 on the reaction container 14 automatically releases pressure after the work is completed, and the spring 43 pops open; the volatile gas leaked in the chamber 23 is discharged through the fan 63, and the fan 63 is connected to the exhaust port 9, and the residual heat inside the chamber 23 is dissipated through the heat dissipation network 12.

[0067] The specific digestion process is to add the sample into the reaction container 14 before the reaction, put the reaction container 14 into the chamber 23, fix it, connect the condensation atomization system, and turn on the condensation atomization system at the same time. Introduce the corresponding acid, alkali or specific reagent required for digestion through the reagent addition port of the condensation atomization system, close the safety cap valve 26, and introduce an external inert gas for pre-pressurization. When the sample is digested, especially the digestion of organic samples, there may be a violent instantaneous reaction to release a large amount of heat. The condensation atomization system should be opened in advance before the digestion reagent is introduced to keep the condensation reflux to prevent instantaneous volatilization and cause the loss of components such as elements in the sample. Open the control panel 6, set the reaction temperature, time, and pressure, and after the parameters are set, start the program, the digestion device starts working, and at the same time, the carrier gas is turned on, the carrier liquid is introduced, and the atomizer works. The liquid remaining on the condenser wall during the reaction is atomized into extremely fine droplets by the atomizer and returned to the reactor under the action of condensation.

[0068] The following examples are only selected to further illustrate the present invention, but should not be limited thereto in practical applications.

[0069] Embodiment 1:

[0070] The concentrated condensation digestion device of the present invention was used to pre-treat a polypropylene particle sample (PP-1), and an experiment was conducted on the determination of Ca, Mg, Al and Zn elements in the treated polypropylene sample solution.

[0071] A concentrated condensation digestion device was used. The external gas used in the reaction container was nitrogen, with a flow rate of 0.5L / min and a pressure of 0.5Mpa; the carrier gas used in the nebulizer was helium, with a flow rate of 0.05L / min and a pressure of 0.1Mpa; the carrier liquid used in the nebulizer was a dilute hydrochloric acid solution, with a mass concentration of 0.5% and a carrier liquid flow rate of 0.1mL / min.

[0072] The reaction vessel has a volume of 200 mL and a spherical shape. The operating temperature is 0 to 350°C. At the highest temperature, the internal pressure can reach 5.0 MPa.

[0073] The material of the reaction container is polytetrafluoroethylene (PTFE), which is transparent and propagable to microwaves.

[0074] The outer wall of the reaction container is a waveguide layer, which is helpful for the penetration of microwaves and good temperature conduction. Its material is a non-polar molecular substance, using PEEK fiber, containing 25% carbon fiber.

[0075] The specific digestion process is to add the sample into the reaction container before the reaction, put the reaction container into the chamber, fix it, connect the condensation atomization system, and turn on the condensation atomization system at the same time. Introduce the reagents required for the corresponding acid of the digestion reaction through the reagent inlet of the condensation atomization system, close the safety cap valve, and introduce external inert gas for pre-pressurization. During sample digestion, especially the digestion of organic samples, there may be a violent instantaneous reaction that releases a large amount of heat. The condensation atomization system should be turned on in advance before the digestion reagent is introduced to maintain condensation reflux to prevent instantaneous volatilization and cause the loss of elements and other components in the sample. Open the control panel, set the reaction temperature, time, and pressure, and after the parameters are set, start the program, the digestion device starts working, and at the same time, turn on the carrier gas, introduce the carrier liquid, and the atomizer generator works. The liquid remaining on the condenser wall during the reaction is atomized into extremely fine droplets by the atomizer generator and returned to the reactor under the action of condensation.

[0076] Spike recovery test

[0077] To investigate the accuracy of the digestion method using the digestion device of the present invention, 10.0 g (accurate to 0.001 g) of a polypropylene particle sample PP-1 (from a domestic petrochemical plant) was accurately weighed, and three parallel samples were weighed, two of which were added with corresponding concentrations of Ca, Mg, Al, and Zn standard substances (taken from 1000 mg / L Ca, Mg, Al, and Zn standard solutions, commercially available inorganic standard solutions).

[0078] According to the method of the present invention, a concentrated digestion device is used, and the digestion program is set as shown in Table 1, and 15.0 mL of hydrochloric acid 15% (commercially available, high-grade purity), 15.0 mL of nitric acid 40% (commercially available, high-grade purity), 10.0 mL of hydrofluoric acid 40% (commercially available, high-grade purity) and 10.0 mL of hydrogen peroxide 30% (commercially available, high-grade purity) are added.

[0079] Table 1 Digestion program settings

[0080]

[0081] After digestion, the digestion liquid was transferred to a 100 mL polytetrafluoroethylene volumetric flask and fixed to volume for the detection of Ca, Mg, Al, and Zn element contents. An inductively coupled plasma atomic emission spectrometer was used, PE Company, USA, model Optima 5300DV, and the instrument working conditions are shown in Table 2. The concentration standard solutions of the Ca, Mg, Al, and Zn elements used for determination were 0 mg / L (blank), 5.0 mg / L, 10.0 mg / L, 15.0 mg / L, 20.0 mg / L, and 25.0 mg / L, and the spiked recovery values ​​were determined and the recovery rates were calculated. The results are shown in Table 3.

[0082] Table 2 Instrument working conditions

[0083]

[0084] Table 3 Recovery test

[0085]

[0086] From the results in Table 3, it can be seen that the recovery rates of calcium, magnesium, aluminum and zinc in the polypropylene particle sample are all between 95% and 105%. The digestion method is accurate and can fully meet the test requirements.

[0087] Embodiment 2:

[0088] The concentrated condensation digestion device of the present invention was used to pre-treat a polyethylene powder sample (PE-1), and an experiment was conducted to determine the elements Ca, Mg, Al, and Zn in the polyethylene sample solution after the treatment.

[0089] A concentrated condensation digestion device was used. The external gas used in the reaction container was helium, with a flow rate of 3.0L / min and a pressure of 7.5Mpa; the carrier gas used in the atomizer was also argon, with a flow rate of 1.5L / min and a pressure of 1.0Mpa; the carrier liquid used in the atomizer was a dilute hydrochloric acid solution, with a mass concentration of 5.0% and a carrier liquid flow rate of 2.5mL / min.

[0090] The reaction vessel has a volume of 2000 mL and a spherical shape. The operating temperature is 0 to 350°C. At the highest temperature, the internal pressure can reach 10.0 MPa.

[0091] The material of the reaction container is polytetrafluoroethylene (PTFE), which is transparent and propagable to microwaves.

[0092] The outer wall of the reaction container is a waveguide layer, which is helpful for the penetration of microwaves and good temperature conduction. Its material is a non-polar molecular substance, using PEEK fiber, containing 25% carbon fiber.

[0093] The specific digestion process is to add the sample into the reaction container before the reaction, put the reaction container into the chamber, fix it, connect the condensation atomization system, and turn on the condensation atomization system at the same time. Introduce the reagents required for the corresponding acid of the digestion reaction through the reagent inlet of the condensation atomization system, close the safety cap valve, and introduce external inert gas for pre-pressurization. During sample digestion, especially the digestion of organic samples, there may be a violent instantaneous reaction that releases a large amount of heat. The condensation atomization system should be turned on in advance before the digestion reagent is introduced to maintain condensation reflux to prevent instantaneous volatilization and cause the loss of elements and other components in the sample. Open the control panel, set the reaction temperature, time, and pressure, and after the parameters are set, start the program, the digestion device starts working, and at the same time, turn on the carrier gas, introduce the carrier liquid, and the atomizer generator works. The liquid remaining on the condenser wall during the reaction is atomized into extremely fine droplets by the atomizer generator and returned to the reactor under the action of condensation.

[0094] 1. Spike recovery test

[0095] To investigate the accuracy of the digestion method using the digestion device of the present invention, 65.0 g (accurate to 0.001 g) of a polyethylene powder sample PE-1 (from a domestic petrochemical plant) was accurately weighed, and three parallel samples were weighed, two of which were added with corresponding concentrations of Ca, Mg, Al, and Zn standard substances (taken from 1000 mg / L Ca, Mg, Al, and Zn standard solutions, commercially available inorganic standard solutions).

[0096] According to the method of the present invention, a concentrated digestion device is used, and the digestion program is set as shown in Table 4, and 125.0 mL of hydrochloric acid 15% (commercially available, high-grade purity), 125.0 mL of nitric acid 40% (commercially available, high-grade purity), 50.0 mL of hydrofluoric acid 40% (commercially available, high-grade purity) and 40.0 mL of hydrogen peroxide 30% (commercially available, high-grade purity) are added.

[0097] Table 4 Digestion program settings

[0098]

[0099] After digestion, the digestion liquid was transferred to a 100mL polytetrafluoroethylene volumetric flask and diluted accordingly according to the determination requirements for the detection of Ca, Mg, Al, and Zn element contents. An inductively coupled plasma atomic emission spectrometer was used, PE Company, USA, model Optima 5300DV, and the instrument working conditions are shown in Table 2. The concentration standard solutions of the Ca, Mg, Al, and Zn elements used for determination were 0 mg / L (blank), 5.0 mg / L, 10.0 mg / L, 15.0 mg / L, 20.0 mg / L, and 25.0 mg / L, respectively. The spike recovery value was determined and the recovery rate was calculated. The results are shown in Table 5.

[0100] Table 5 Recovery test

[0101]

[0102] From the results in Table 5, it can be seen that the recovery rates of calcium, magnesium, aluminum and zinc in the polyethylene powder sample are all between 95% and 105%. The digestion method is accurate and can fully meet the test requirements.

[0103] Embodiment 3:

[0104] The concentrated condensation digestion device of the present invention was used to pre-treat the hydrogenation catalyst sample (CAT-1), and an experiment was conducted on the determination of Ni, Fe, and Cu elements in the treated hydrogenation catalyst sample solution.

[0105] A concentrated condensation digestion device was used. The external gas used in the reaction container was nitrogen, with a flow rate of 1.0L / min and a pressure of 1.5Mpa; the carrier gas used in the nebulizer was helium, with a flow rate of 0.1L / min and a pressure of 0.2Mpa; the carrier liquid used in the nebulizer was a dilute hydrochloric acid solution, with a mass concentration of 1.0% and a carrier liquid flow rate of 0.5mL / min.

[0106] The reaction vessel has a volume of 500 mL and a cylindrical shape. The operating temperature is 0 to 350°C. At the highest temperature, the internal pressure can reach 6.0 MPa.

[0107] The material of the reaction container is polytetrafluoroethylene (PTFE), which is transparent and propagable to microwaves.

[0108] The outer wall of the reaction container is a waveguide layer, which is helpful for the penetration of microwaves and good temperature conduction. Its material is a non-polar molecular substance, using PEEK fiber, containing 25% carbon fiber.

[0109] The specific digestion process is to add the sample into the reaction container before the reaction, put the reaction container into the chamber, fix it, connect the condensation atomization system, and turn on the condensation atomization system at the same time. Introduce the reagents required for the corresponding acid of the digestion reaction through the reagent inlet of the condensation atomization system, close the safety cap valve, and introduce external inert gas for pre-pressurization. When the sample is digested, there may be a violent instantaneous reaction that releases a large amount of heat. The condensation atomization system should be turned on in advance before the digestion reagent is introduced to maintain condensation reflux to prevent instantaneous volatilization and cause the loss of elements and other components in the sample. Open the control panel, set the reaction temperature, time, and pressure. After the parameters are set, start the program, the digestion device starts working, and at the same time, turn on the carrier gas, introduce the carrier liquid, and the atomizer generator works. The liquid remaining on the condenser wall during the reaction is atomized into extremely fine droplets by the atomizer generator and returned to the reactor under the action of condensation.

[0110] Spike recovery test

[0111] The accuracy of the digestion method using the digestion device of the present invention was investigated. 25.0 g (accurate to 0.001 g) of the hydrogenation catalyst sample CAT-1 (from a domestic petrochemical plant) was accurately weighed (it needed to be ground into powder in advance and then used for weighing). Three parallel samples were weighed respectively, and two of them were added with corresponding concentrations of Ni, Fe, and Cu standard substances (taken from 1000 mg / L Ni, Fe, and Cu standard solutions, commercially available inorganic standard solutions).

[0112] According to the method of the present invention, a concentrated digestion device was used, and the digestion program was set as shown in Table 6, and 25.0 mL of hydrochloric acid 15% (commercially available, high-grade purity), 25.0 mL of nitric acid 40% (commercially available, high-grade purity), and 20.0 mL of hydrofluoric acid 40% (commercially available, high-grade purity) were added.

[0113] Table 6 Digestion program settings

[0114]

[0115] After digestion, the digestion liquid was transferred to a 100mL polytetrafluoroethylene volumetric flask and fixed to volume for the detection of Ni, Fe, and Cu element contents. An inductively coupled plasma atomic emission spectrometer was used, PE Company, USA, model Optima 5300DV, and the instrument working conditions are shown in Table 2. The concentration standard solutions of Ni, Fe, and Cu elements were 0 mg / L (blank), 5.0 mg / L, 10.0 mg / L, 15.0 mg / L, 20.0 mg / L, and 25.0 mg / L, respectively. If the concentration of the element exceeds the curve range, it is diluted and measured as needed. The spike recovery value was determined and the recovery rate was calculated. The results are shown in Table 7.

[0116] Table 7 Recovery test

[0117]

[0118] From the results in Table 7, it can be seen that the recovery rates of the three elements Ni, Fe and Cu in the polyethylene sample are all between 95% and 105%. The digestion method is accurate and can fully meet the test requirements.

[0119] Embodiment 4:

[0120] The concentrated condensation digestion device of the present invention was used to pre-treat an organic liquid catalyst sample (CAT-2), and an experiment was conducted to determine the Cr, Fe, and Al elements in the treated hydrogenation catalyst sample solution.

[0121] A concentrated condensation digestion device was used. The external gas used in the reaction container was nitrogen, with a flow rate of 1.5L / min and a pressure of 4.0Mpa; the carrier gas used in the nebulizer was helium, with a flow rate of 0.3L / min and a pressure of 0.3Mpa; the carrier liquid used in the nebulizer was a dilute hydrochloric acid solution, with a mass concentration of 2.5% and a carrier liquid flow rate of 2.0mL / min.

[0122] The reaction vessel has a volume of 400 mL and a cylindrical shape. The operating temperature is 0 to 350°C. At the highest temperature, the internal pressure can reach 7.5 MPa.

[0123] The material of the reaction container is polytetrafluoroethylene (PTFE), which is transparent and propagable to microwaves.

[0124] The outer wall of the reaction container is a waveguide layer, which is helpful for the penetration of microwaves and good temperature conduction. Its material is a non-polar molecular substance, using PEEK fiber, containing 25% carbon fiber.

[0125] The specific digestion process is to add the sample into the reaction container before the reaction, put the reaction container into the chamber, fix it, connect the condensation atomization system, and turn on the condensation atomization system at the same time. Introduce the reagents required for the corresponding acid of the digestion reaction through the reagent inlet of the condensation atomization system, close the safety cap valve, and introduce external inert gas for pre-pressurization. During sample digestion, especially the digestion of organic samples, there may be a violent instantaneous reaction that releases a large amount of heat. The condensation atomization system should be turned on in advance before the digestion reagent is introduced to maintain condensation reflux to prevent instantaneous volatilization and cause the loss of elements and other components in the sample. Open the control panel, set the reaction temperature, time, and pressure, and after the parameters are set, start the program, the digestion device starts working, and at the same time, turn on the carrier gas, introduce the carrier liquid, and the atomizer generator works. The liquid remaining on the condenser wall during the reaction is atomized into extremely fine droplets by the atomizer generator and returned to the reactor under the action of condensation.

[0126] Spike recovery test

[0127] The accuracy of the digestion method using the digestion device of the present invention was investigated. 10.0 g (accurate to 0.001 g) of an organic liquid catalyst sample CAT-2 (from a domestic petrochemical plant) was accurately weighed, and three parallel samples were weighed respectively, two of which were added with corresponding concentrations of Cr, Fe, and Al standard substances (taken from 1000 mg / L Cr, Fe, and Al standard solutions, commercially available organic standard solutions).

[0128] According to the method of the present invention, a concentrated digestion device is used, and the digestion program is set as shown in Table 8, and 20.0 mL of hydrochloric acid 20% (commercially available, top-grade purity), 20.0 mL of nitric acid 45% (commercially available, top-grade purity), 15.0 mL of hydrofluoric acid 30% (commercially available, top-grade purity) and 20.0 mL of hydrogen peroxide 30% (commercially available, top-grade purity) are added.

[0129] Table 8 Digestion program settings

[0130]

[0131] After digestion, the digestion liquid was transferred to a 100mL polytetrafluoroethylene volumetric flask and fixed to volume for the detection of Cr, Fe, and Al content. An inductively coupled plasma atomic emission spectrometer was used, PE Company, USA, model Optima 5300DV, and the instrument working conditions are shown in Table 2. The concentration standard solutions of Cr, Fe, and Al elements used for determination were 0 mg / L (blank), 5.0 mg / L, 10.0 mg / L, 15.0 mg / L, 20.0 mg / L, and 25.0 mg / L, respectively. If the concentration of the element exceeds the curve range, it is diluted and determined as needed. The spike recovery value was determined and the recovery rate was calculated. The results are shown in Table 9.

[0132] Table 9 Recovery test

[0133]

[0134]

[0135] From the results in Table 9, it can be seen that the recovery rates of the three elements Cr, Fe and Al in the polyethylene sample are all between 95% and 105%. The digestion method is accurate and can fully meet the test requirements.

[0136] Comparative Example 1:

[0137] For the analysis of metal elements Ti, Zr and Cr in polyethylene products, microwave digestion and ashing are still widely used at home and abroad. The ashing process takes a long time, causes volatilization loss of elements, and has high pollution. Although the traditional microwave digestion process is fast, the sample is easily incompletely digested. The sample sampling volume is limited by the digestion container, the sample volume is too low, and the reproducibility is poor for low-content samples. This method uses concentrated condensation microwave digestion to treat samples. The digestion sample volume is large, and the condensation reflux prevents the loss of volatile elements. The method is simple, fast, accurate, and low-pressure, which is safer than traditional microwave digestion.

[0138] 1. Test instruments and reagents

[0139] Aggregate condensation digestion device.

[0140] Microwave digestion apparatus, CEM, USA.

[0141] Inductively coupled plasma atomic emission spectrometer, PE Company, USA, model Optima 5300DV, instrument operating conditions are shown in Table 2.

[0142] Polyethylene, from a domestic petrochemical plant (sample numbers 01 to 06).

[0143] Ti, Zr, Cr standard solutions (1000 mg / L) were produced by the National Center for Standard Materials. When used, a mixed standard solution of Ti, Zr, Cr in the required range of the sample was prepared. The measurement was performed according to the instrument working conditions in Table 2.

[0144] 2. Test steps

[0145] The concentrated condensation digestion device of the present invention is used to pre-treat polyethylene samples (01-06), and an experiment is carried out to determine the Ti, Zr and Cr elements in the polyethylene sample solutions after the treatment.

[0146] A concentrated condensation digestion device was used. The external gas used in the reaction container was nitrogen, with a flow rate of 0.8L / min and a pressure of 4.5Mpa; the carrier gas used in the atomizer was argon, with a flow rate of 0.6L / min and a pressure of 0.4Mpa; the carrier liquid used in the atomizer was a dilute nitric acid solution, with a mass concentration of 3.5% and a carrier liquid flow rate of 2.6mL / min.

[0147] The reaction vessel has a volume of 400 mL and a round shape. The operating temperature is 0 to 350°C. At the highest temperature, the internal pressure can reach 8.0 MPa.

[0148] The material of the reaction container is polytetrafluoroethylene (PTFE), which is transparent and propagable to microwaves.

[0149] The outer wall of the reaction container is a waveguide layer, which is helpful for the penetration of microwaves and good temperature conduction. Its material is a non-polar molecular substance, using PEEK fiber, containing 25% carbon fiber.

[0150] The specific digestion process is to add the sample into the reaction container before the reaction, put the reaction container into the chamber, fix it, connect the condensation atomization system, and turn on the condensation atomization system at the same time. Introduce the reagents required for the corresponding acid of the digestion reaction through the reagent inlet of the condensation atomization system, close the safety cap valve, and introduce external inert gas for pre-pressurization. During sample digestion, especially the digestion of organic samples, there may be a violent instantaneous reaction that releases a large amount of heat. The condensation atomization system should be turned on in advance before the digestion reagent is introduced to maintain condensation reflux to prevent instantaneous volatilization and cause the loss of elements and other components in the sample. Open the control panel, set the reaction temperature, time, and pressure, and after the parameters are set, start the program, the digestion device starts working, and at the same time, turn on the carrier gas, introduce the carrier liquid, and the atomizer generator works. The liquid remaining on the condenser wall during the reaction is atomized into extremely fine droplets by the atomizer generator and returned to the reactor under the action of condensation.

[0151] Accurately weigh 20.0 g of polyethylene product samples 01-06 (from a domestic petrochemical plant), use a concentrated digestion device according to the method of the present invention, set the digestion program as shown in Table 10, add 20.0 mL of hydrochloric acid 25% (commercially available, high-grade purity), 20.0 mL of nitric acid 55% (commercially available, high-grade purity), 15.0 mL of hydrofluoric acid 38% (commercially available, high-grade purity) and 20.0 mL of hydrogen peroxide 30% (commercially available, high-grade purity).

[0152] Table 10 Digestion program settings

[0153]

[0154] After digestion, the digestion liquid was transferred to a 100mL polytetrafluoroethylene volumetric flask for determination of Ti, Zr and Cr content. An inductively coupled plasma atomic emission spectrometer was used, PE Company, USA, model Optima 5300DV, and the instrument working conditions are shown in Table 2. The concentration standard solutions of Ti, Zr and Cr elements used for determination were 0mg / L (blank), 5.0mg / L, 10.0mg / L, 15.0mg / L, 20.0mg / L and 25.0mg / L, respectively. If the concentration of the element was beyond the curve range, it was diluted and determined as needed.

[0155] Accurately weigh 0.400g of the above polyethylene sample (sample numbers are 01 to 06) in a digestion tank, add 5mL of nitric acid, 5mL of hydrochloric acid, and 2mL of hydrogen peroxide, shake slowly, cover the outer cover, and place it on the digestion tank rack. Set according to the microwave digestion program in Table 11 and start sample digestion. After the digestion program is completed and the temperature in the cavity cools to room temperature, take out the sample tank, transfer the digestion solution in the tank to a 50mL beaker with deionized water, and then place it on a 180℃ hot plate to heat to remove excess acid. Heat until a small amount of sample remains, cool it down, transfer it to a 50mL volumetric flask with deionized water, and dilute to the mark for measurement. Prepare a sample blank in the same way and repeat the above steps.

[0156] Table 11 CEM microwave digestion program

[0157]

[0158] 3. Test results

[0159] In order to verify the completeness of digestion and the accuracy of the measurement results of the digestion method using the clustering digestion device, the results of the actual sample after clustering and condensation digestion were compared with the results of the same sample measured by traditional microwave digestion. The results are shown in Table 12.

[0160] Table 12 Comparative test results

[0161]

[0162]

[0163] As can be seen from Table 12, the results of traditional microwave digestion for Ti, Zr, and Cr are obviously lower than those of this method, and a small amount of undigested and adhered samples are found to remain at the bottom of the traditional microwave digestion tank, while the concentrated condensation digestion reaction vessel is completely digested and the solution is clear. Therefore, the use of this concentrated condensation digestion device to treat large-mass polyethylene samples has achieved satisfactory results.

[0164] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, technicians familiar with the field may make various corresponding changes and deformations based on the present invention, but these corresponding changes and deformations should all fall within the scope of protection of the claims of the present invention.

Claims

1. A concentrated condensation digestion device, It is characterized in that include: A body, a reaction container, and a condensation atomization system. Reagents are introduced into the reaction container, and an inert gas is introduced for pre-pressurization. The condensation atomization system is connected to the reaction container and placed above the reaction container; The machine body comprises a chamber, a machine door, a machine cover, a control system, a microwave generating system, and a base. The chamber is located inside the machine body and is opened or closed by the machine door. The machine cover is located on the top of the machine body. The control system is located on the top surface or one side surface of the machine body. The microwave generating system is connected to the chamber. The base is not a turntable type, but a bottom plate fixed to the bottom surface of the chamber. The reaction container is placed on the base of the chamber. The condensation atomization system comprises a reflux tank, an atomization generator, an external interface, a condenser, a circulating inner tube, a circulating outer tube, a condenser inner circulation water inlet, a condenser inner circulation water outlet, a condenser outer circulation water inlet, a condenser outer circulation water outlet, and a safety cap valve, wherein the safety cap valve is located at the top of the condensation atomization system, the lower end of the condenser is connected to the reflux tank, the side end of the reflux tank is connected to the atomization generator, the upper part of the reflux tank is provided with an external interface connected to an external gas; the bottom of the condenser is provided with a condenser lower outlet, and the condenser lower outlet is connected to the reaction vessel; The atomizer generator is a glass concentric atomizer, the center of which is a capillary tube, the capillary tube is parallel to the airflow of the carrier gas, the carrier gas is introduced through an external air inlet instrument port on one side of the body, the airflow quickly passes through the end of the capillary tube, meets the carrier liquid in the atomizer generator at the atomizer nozzle and shears the liquid to form tiny droplets, the tiny droplets are sprayed out with the carrier gas, condensed through the condenser tube to form condensate, the condensate droplets flow back into the reflux pool, and then flow into the reaction container.

2. The concentrated condensation digestion device according to claim 1, It is characterized in that The chamber structure is a polyhedron, the left and right sides and the front and back sides are symmetrical surfaces, or the diagonal surfaces are symmetrical, and the upper and lower sides are symmetrical surfaces, and it is composed of at least 8 inner surfaces; the chamber is a closed rectangular industrial resonant cavity; the material of the chamber is all stainless steel or polytetrafluoroethylene, and is provided with a multi-layer anti-corrosion coating; the chamber is also provided with an exhaust system and a cooling system, and the exhaust volume in the chamber is not less than 1.0m 3 / min.

3. The concentrated condensation digestion device according to claim 1, It is characterized in that The machine door is equipped with double or triple independent interlocking sensing equipment. The power is cut off when the machine door is opened, and the microwave generating system cannot work when the machine door is not closed. The machine door is also provided with an observation window, and the outside of the machine body is provided with a heat dissipation net. The mesh size of the metal grid or wire mesh in the observation window and the heat dissipation net is 0.02-0.2 mm.

4. The concentrated condensation digestion device according to claim 1, It is characterized in that The body is designed as one mold or multiple molds.

5. The concentrated condensation digestion device according to claim 1, It is characterized in that The shape of the reaction container is selected from one of spherical, cylindrical, cubic and polyhedral shapes; the material of the reaction container is one of polytetrafluoroethylene (PTFE), perfluoroalkoxyethylene (PFA), modified polytetrafluoroethylene (TFM) and quartz; the outer wall of the reaction container is a waveguide layer, and its material should be a non-polar molecular substance; the material of the waveguide layer includes polyetheretherketone (PEEK) fiber, and the polyetheretherketone (PEEK) fiber contains more than 10% carbon fiber or more than 10% glass fiber.

6. The concentrated condensation digestion device according to claim 1, It is characterized in that There is a spring piece in the safety cap valve. When the pressure in the reaction container exceeds the tolerable pressure, the safety cap valve automatically opens to balance the pressure. The spring piece is pressed tightly with ceramic material.

7. The concentrated condensation digestion device according to claim 1, It is characterized in that The volume of the reaction container is 100 mL to 2000 mL; the temperature in the reaction container is 0 to 350°C.

8. The concentrated condensation digestion device according to claim 1, It is characterized in that The reagent is an acid, an alkali or other reagent required for digestion, the acid is at least one of hydrochloric acid, nitric acid, phosphoric acid, hydrofluoric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, perchloric acid, boric acid, oxalic acid, tartaric acid, and citric acid; the alkali is at least one of ammonia water and sodium hydroxide, and the other reagent required for digestion is hydrogen peroxide.

9. The concentrated condensation digestion device according to claim 1, It is characterized in that The number of the external gas inlet instrument ports is two, and the external gas inlet instrument ports are used to introduce different gases for switching between the external gas of the reaction container and the carrier gas of the atomizer generator. The external gas of the reaction container is an inert gas, and the inert gas is selected from at least one of nitrogen, helium and argon, with a flow rate of 0.5 to 3.0 L / min and a pressure of 0.5 to 8.0 MPa; the carrier gas of the atomizer generator is an inert gas, and the inert gas is at least one of nitrogen, helium and argon, with a flow rate of 0.05 to 1.5 L / min and a pressure of 0.1 to 1.0 MPa; the carrier liquid in the atomizer generator is a dilute acid solution, and the dilute acid solution is hydrochloric acid and / or nitric acid, and the mass concentration of the hydrochloric acid and / or nitric acid is 0.5 to 5.0%, and the flow rate of the carrier liquid is 0.1 to 2.5 mL / min.

10. The concentrated condensation digestion device according to claim 1, It is characterized in that A temperature sensor probe and a pressure sensor probe are provided in the chamber. The temperature in the chamber is 0-350°C with a temperature control accuracy of ±0.05°C. The pressure in the chamber is 0-10.0MPa with a pressure control accuracy of 0.01MPa. A pipeline is provided in the chamber to connect the reaction container with the outside world.

11. The concentrated condensation digestion device according to claim 1, It is characterized in that The control system comprises a control panel and a display screen, and the display screen is designed as a touch screen.

12. The concentrated condensation digestion device according to claim 1, It is characterized in that Internal components are arranged between the chamber and the body, and the internal components are a magnetron, a waveguide, a diode, a refrigerator, a transformer, and a fan. The magnetron is connected to the waveguide, and the waveguide is arranged between the magnetron and the chamber.

13. The concentrated condensation digestion device according to claim 1, It is characterized in that The refrigerator is a semiconductor refrigerator, which is used to cool the chamber, has an operating temperature of 0°C to 25°C, and a control temperature of 15°C to 20°C.

14. The concentrated condensation digestion device according to claim 1, It is characterized in that The microwave frequency of the microwave generating system is 2450 MHz, and the microwave output power is 0-1600 W, which is automatically and continuously adjustable; the microwave of the microwave generating system is a non-pulse continuous automatic power frequency conversion type.

15. The concentrated condensation digestion device according to claim 1, It is characterized in that The reaction container is connected to the lower outlet of the condenser through a fixing ring, and the fixing ring is composed of an outer interlayer, an inner interlayer, a first clip, a second clip, a third clip, a fourth clip, a first screw, a second screw, a third screw, and a fourth screw; the first clip and the second clip are fixed by the first screw and the second screw; the third clip and the fourth clip are fixed by the third screw and the fourth screw.

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