Pre-treatment device and method for free silicon dioxide detection

Abstract

The present application relates to the technical field of dust detection, and particularly relates to a free silicon dioxide detection pretreatment device and method. The technical scheme comprises a grinding unit, an integrated sample processing cabin and a hydrofluoric acid sealing cabin. The present application realizes the full-chain automation from sample grinding, drying, digestion, filtering, washing to final data report generation through the integrated sample processing cabin, integrates digestion and filtering, switches the filter membrane through air pressure control, realizes the integration of the digestion and filtering process, avoids sample transfer, and ensures the sealing and safety of the hydrofluoric acid treatment process through the hydrofluoric acid sealing cabin.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of dust detection, in particular to a free silicon dioxide detection pretreatment device and method. BACKGROUND

[0002] In the field of environmental and occupational health detection, it is crucial to accurately determine the content of free silicon dioxide in the air or other media, which is of key significance to the evaluation of occupational hazards in the workplace and environmental quality. Currently, the pretreatment process of free silicon dioxide detection mainly relies on traditional manual operation.

[0003] The document with publication number CN117554142B points out that the existing free silicon dioxide detection is by pyrophosphoric acid method, and the technical requirements for the tester are relatively high during the detection process. Pure manual operation may cause large errors if not careful, and the operation period is long and tedious. Based on the existing pyrophosphoric acid method principle, the digestion of the sample and the separation operation of free silicon dioxide are only in one glass test tube, there is no transfer of the sample digestion liquid, and the free silicon dioxide residue will not be lost; using a ceramic filter core to suck the supernatant of the digestion liquid diluent will not only leave free silicon dioxide residue in the glass test tube, but also intercept a small amount of free silicon dioxide suspended in the diluent and free silicon dioxide floating on the surface of the diluent; the glass test tube, glass beads, free silicon dioxide and ceramic filter core can be constant weight after baking in a constant temperature drying oven, and since slow quantitative filter paper is not used, it is not necessary to burn in a muffle furnace, so the detection process is simple and fast; the glass test tube, glass beads, ceramic filter core, etc. are easier to constant weight, and the detection result is stable.

[0004] However, the existing operation mode still has many drawbacks. During the digestion process, it is difficult for manual operation to accurately control the temperature and time, resulting in unstable digestion effect and affecting the accuracy of the subsequent detection results. Moreover, in the filtration and washing links, manual operation is easy to introduce impurities, causing sample pollution, and the whole process is tedious, consuming a lot of manpower and time cost. In addition, when using dangerous chemicals such as hydrofluoric acid for treatment, manual operation has great safety hazards, such as leakage which may cause serious physical harm to the operator. Therefore, an efficient, accurate and safe integrated pretreatment device and intelligent control method are needed to improve the current situation. SUMMARY

[0005] The purpose of the present application is to solve the problems in the background art and provide a free silicon dioxide detection pretreatment device and method.

[0006] The technical scheme of the present application is a free silicon dioxide detection pretreatment device and method, which comprises:

[0007] The grinding unit comprises a grinding bin, a top of the grinding bin is a sample inlet, an ultrasonic oscillator and an air flow circulating device are installed in the grinding bin;

[0008] The integrated sample processing cabin comprises an acid-resistant cavity, a multi-stage filter membrane switching device arranged at a bottom of the acid-resistant cavity, a vacuum drying bin, an integrated heating plate installed in the acid-resistant cavity, a pyrophosphoric acid inlet arranged at one side of the acid-resistant cavity, and a temperature control unit and a negative pressure adsorption device.

[0009] The hydrofluoric acid sealed cabin comprises a sealed cabin and an alkaline neutralization tank, the sealed cabin is further provided with a negative pressure suction inlet and a hydrofluoric acid inlet, and the sealed cabin is further provided with a leakage emergency treatment device.

[0010] Preferably, the multi-stage filter membrane switching device comprises a pneumatic push rod, two trays distributed upward and downward are installed on the pneumatic push rod, and the multi-stage filter membrane switching device further comprises PTFE filter membranes and nylon screens arranged on the two trays respectively.

[0011] Preferably, the integrated heating plate is divided into at least three ceramic heating plates, the integrated heating plate is electrically connected with the temperature control unit, the temperature control unit comprises a PID controller, a solid-state relay, a touch screen and a K-type thermocouple temperature sensor arranged in the acid-resistant cavity.

[0012] Preferably, the temperature control unit is provided with a segmented temperature rising program:

[0013] The first stage is 120 DEG C pre-digestion for 20 min;

[0014] The second stage is 240 DEG C constant temperature for 40 min;

[0015] The third stage is 250 DEG C maintenance for 10 min;

[0016] Preferably, a conveying belt is arranged between the vacuum drying bin and the grinding bin, an infrared radiation heating device and a vacuum pump are arranged in the vacuum drying bin, a multi-channel liquid distributor, an electric conductivity sensor and a weighing device are further arranged outside the acid-resistant cavity, and an eddy current stirrer is arranged in the acid-resistant cavity.

[0017] Preferably, the leakage emergency treatment device comprises an HF concentration sensor arranged in the sealed cabin and a neutralizing agent spraying device, a detection threshold of the HF concentration sensor is set to 0.5 ppm, and the sealed cabin is further provided with a pressure sensor and a pressure relief valve.

[0018] The free silicon dioxide detection pretreatment method comprises the following steps:

[0019] The sample pretreatment step is as follows: the collected sample is put into the grinding bin through the sample inlet, the ultrasonic oscillator and the air flow circulating device are started to crush, and then the ground sample is transferred to the vacuum drying bin through the conveying belt, and the infrared radiation heating and the vacuum pump are started to dry.

[0020] Digestion and filtration steps: The dry sample is injected into an acid-resistant cavity, and pyrophosphoric acid solution is added from the pyrophosphoric acid inlet at a ratio of 1:10. Three-stage heating is performed by a temperature control unit built-in segmented temperature program control integrated heating plate, and a vortex stirrer is started at the same time. After digestion is completed, a negative pressure adsorption device is triggered, and a PTFE filter membrane with a pore diameter of 0.45 μm is pushed to the working position for filtration. The waste liquid is discharged into an acid-resistant waste tank;

[0021] Washing and drying steps: A multi-channel liquid distributor sequentially injects hot water, dilute hydrochloric acid and deionized water at a temperature of 80 DEG C for washing. The conductivity sensor monitors the conductivity of the washing liquid in real time, and the washing is stopped when the standard is reached. Subsequently, the washed residue is transferred to a vacuum drying bin for synchronous operation of infrared radiation and vacuum dewatering, and the weighing module automatically records the residue mass;

[0022] Safety hydrofluoric acid treatment step: If total silicon detection is required, the sample is transferred to a hydrofluoric acid sealed cabin. A quantitative pump injects hydrofluoric acid at a rate of 1 mL / min, and the concentration is 40%. A pressure sensor monitors the pressure in the cabin. When the HF concentration sensor detects a value greater than 0.5 ppm, the neutralizing agent spraying device is started within 0.2 s, and the negative pressure adsorption system recovers gaseous HF to an alkaline neutralization tank.

[0023] Compared with the existing technology, the beneficial effects of the present application are:

[0024] 1. The present application realizes the full-chain automation from sample grinding, drying, digestion, filtration, washing to the final data report generation. Manual intervention is only required for initial sample injection and instruction input, which reduces a large number of tedious manual operation links, greatly improves the detection efficiency, and can meet the demand of large-scale sample detection.

[0025] 2. Compared with the traditional method, the sample is easily lost during the process of transferring from the digestion container to the filtration device. The present application integrates the sample processing cabin, integrates the digestion and filtration, and realizes the integration of the digestion and filtration process by controlling the filter membrane switching through air pressure, thereby avoiding the sample transfer.

[0026] 3. The hydrofluoric acid sealed cabin ensures the sealing and safety of the hydrofluoric acid treatment process. The pressure sensor, HF concentration sensor, neutralizing agent spraying device and negative pressure adsorption system form a comprehensive safety protection system. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is a structural schematic diagram of the present application;

[0028] Figure 2 is a flowchart of the present application.

[0029] Reference signs: 1, acid-resistant cavity; 2, grinding bin; 4, vacuum drying bin; 5, sealed cabin; 6, multi-stage filter membrane switching device; 7, alkaline neutralization tank; 11, integrated heating plate; 12, vortex stirrer; 21, ultrasonic oscillator; 22, air flow circulating device; 51, negative pressure suction inlet; 52, hydrofluoric acid inlet; 100, sample inlet; 200, pyrophosphoric acid inlet; 500, negative pressure adsorption device. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all.

[0031] Referring to the drawings Figure 1 , the free silicon dioxide detection pretreatment device, the grinding unit, including the grinding bin 2, the top of the grinding bin 2 is the sample inlet 100, the ultrasonic oscillator 21 and the air flow circulating device 22 are installed in the grinding bin 2;

[0032] The integrated sample processing cabin includes the acid-resistant cavity 1 and the multi-stage filter membrane switching device 6 arranged at the bottom of the acid-resistant cavity 1, further includes the vacuum drying bin 4, the integrated heating plate 11 is further installed in the acid-resistant cavity 1, one side of the acid-resistant cavity 1 is provided with the pyrophosphoric acid inlet 200, and the integrated sample processing cabin is further provided with the temperature control unit and the negative pressure adsorption device 500;

[0033] The hydrofluoric acid sealed cabin includes the sealed cabin 5 and the alkaline neutralization tank 7, the sealed cabin 5 is further provided with the negative pressure suction inlet 51 and the hydrofluoric acid inlet 52, and the sealed cabin 5 is further provided with the leakage emergency treatment device;

[0034] The traditional method relies on manual operation of glass test tubes, the integrated sample processing cabin is adopted in the present application, the functions of digestion, filtration, washing and drying are integrated, the manual transfer link is eliminated, the filter level switching can be quickly completed subsequently, the efficiency is improved compared with the glass test tube ceramic filter core mode, and the safety is greatly improved by adopting the independent sealed cabin, the negative pressure adsorption and the leakage emergency treatment device for hydrofluoric acid treatment.

[0035] Specifically, the multi-stage filter membrane switching device 6 includes a pneumatic push rod, two trays are arranged on the pneumatic push rod in a vertical distribution mode, the multi-stage filter membrane switching device 6 further includes PTFE filter membranes and nylon screens respectively arranged on the two trays, the two trays are driven to horizontally displace by the pneumatic push rod, and zero-contact switching is realized.

[0036] In the embodiment, the integrated heating plate 11 is divided into at least three ceramic heating plates, the integrated heating plate 11 is electrically connected with the temperature control unit, the temperature control unit includes a PID controller, a solid-state relay, a touch screen and a K-type thermocouple temperature sensor located in the acid-resistant cavity 1;

[0037] In addition, the temperature control unit is built-in segmented temperature rising program, including:

[0038] The first stage: 120 DEG C pre-digestion 20 min;

[0039] The second stage: 240 DEG C ± 1 DEG C constant temperature 40 min;

[0040] The third stage: 250 DEG C ± 1 DEG C maintain 10 min;

[0041] Specifically, the ceramic heating plate is the key component to provide the heat required for digestion, according to the real-time feedback of the internal temperature of the cavity by the K-type thermocouple temperature sensor, the power of the ceramic heating plate is dynamically adjusted.

[0042] For example, in different stages of the gradient temperature rising program, when the temperature needs to be raised, the module will increase the power of the heating plate, and when the set temperature is approached, the power will be appropriately reduced to avoid temperature overshoot; when the temperature is raised to 120 DEG C in stage 1, the module will quickly increase the power of the heating plate to make the temperature rise, and when the temperature approaches 120 DEG C, the power will be gradually reduced to ensure that the temperature is stable at 120 DEG C ± 2 DEG C;

[0043] In addition, during the entire digestion process, the temperature control unit continuously monitors the temperature change to ensure that the temperature fluctuation is within a very small range, and for the requirements of 240 DEG C ± 1 DEG C in stage 2 and 250 DEG C ± 1 DEG C in stage 3, the module will continuously adjust the power of the heating plate to make the temperature stable around the set value. By accurately controlling the temperature, the effect and consistency of sample digestion are ensured, and the problems of incomplete digestion or over-digestion caused by temperature fluctuation are avoided.

[0044] It should be further pointed out that a conveying belt is arranged between the vacuum drying bin 4 and the grinding bin 2, an infrared radiation heating device and a vacuum pump are arranged in the vacuum drying bin 4, a multi-channel liquid distributor, an electrical conductivity sensor and a weighing device are further arranged outside the acid-resistant cavity 1, and an eddy current stirrer 12 is arranged in the acid-resistant cavity 1.

[0045] The leakage emergency treatment device comprises an HF concentration sensor arranged in the sealed cabin 5 and a neutralizing agent spraying device, and the detection threshold of the HF concentration sensor is set to 0.5 ppm, and the sealed cabin 5 is further provided with a pressure sensor and a pressure relief valve.

[0046] The application also discloses a silica detection pretreatment method, which comprises the following steps:

[0047] The sample pretreatment step is as follows: the collected sample is put into the grinding bin 2 through the sample inlet 100, the ultrasonic oscillator 21 and the airflow circulating device 22 are started to crush, and then the ground sample is transferred to the vacuum drying bin 4 through the conveying belt, and the infrared radiation heating and the vacuum pump are started to dry;

[0048] Digestion and filtration step: inject the dry sample into the acid-resistant cavity 1, add pyrophosphoric acid solution from the pyrophosphoric acid inlet 200 at a ratio of 1:10, control the integrated heating plate through the built-in staged temperature program of the temperature control unit to perform three-stage heating, and start the vortex stirrer at the same time. After digestion is completed, trigger the negative pressure adsorption device 500, and at the same time, push the PTFE filter membrane with a pore diameter of 0.45 mu m to the working position for filtration, and discharge the waste liquid into the acid-resistant waste liquid tank;

[0049] Washing and drying step: the multi-channel liquid distributor sequentially injects hot water with a temperature of 80 DEG C, dilute hydrochloric acid and deionized water for washing, the conductivity sensor monitors the conductivity of the washing liquid in real time, and the washing is stopped after reaching the standard. Subsequently, the residue after washing is transferred to the vacuum drying bin for synchronous operation of infrared radiation and vacuum dewatering, and the weighing module automatically records the mass of the residue;

[0050] Safety hydrofluoric acid treatment step: if total silicon detection is required, the sample is transferred to the hydrofluoric acid sealed cabin, the quantitative pump injects hydrofluoric acid at a rate of 1 mL / min, the concentration is 40%, the pressure sensor monitors the pressure in the cabin, and the pressure relief valve is triggered when the limit is exceeded. When the HF concentration sensor detects a value > 0.5 ppm, the neutralizing agent spraying device is started within 0.2 s, and the negative pressure adsorption system recovers gaseous HF to the alkaline neutralization tank.

[0051] And it needs to be explained that in the digestion and filtration step, the temperature stabilization time of stage 2 of the gradient temperature program is automatically determined by the temperature change rate, and when the temperature fluctuation is < 0.3 DEG C for 5 consecutive minutes, the next stage is entered;

[0052] In addition, pulse suction (suction for 30 seconds / pause for 5 seconds) is adopted for filtration to prevent filter membrane blockage;

[0053] In the safety hydrofluoric acid treatment step, the neutralizing agent is configured at a volume ratio of 1:10, and the spray head of the neutralizing agent spraying device is a fan-shaped spray head covering an area of > 80% of the leakage area.

[0054] In the description of the present application, it should be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0055] In addition, the terms "first", "second", etc. are used only for the purpose of description, and should not be understood as indicating or implying relative importance or implying the number of the technical features indicated. Therefore, the features defined as "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0056] The above description is merely preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can make equivalent replacements or changes within the technical range disclosed by the present application according to the technical solutions and the inventive concept of the present application, which should be covered within the protection scope of the present application.

Claims

1. A device for the pre-treatment of free silicon dioxide, characterized in that The application relates to a sample pretreatment device for a hydrogen fluoride acid sealed cabin, which comprises the following parts. A grinding unit, which comprises a grinding bin, the top of the grinding bin being a sample inlet, an ultrasonic oscillator and an air flow circulating device being arranged in the grinding bin; An integrated sample treatment cabin, which comprises an acid-resistant cavity and a multi-stage filter membrane switching device arranged at the bottom of the acid-resistant cavity, and further comprises a vacuum drying bin, an integrated heating plate being arranged in the acid-resistant cavity, one side of the acid-resistant cavity being provided with a pyrophosphoric acid inlet, the integrated sample treatment cabin being further provided with a temperature control unit and a negative pressure adsorption device; A hydrogen fluoride acid sealed cabin, which comprises a sealed cabin and an alkaline neutralization tank, the sealed cabin being further provided with a negative pressure suction inlet and a hydrogen fluoride acid inlet, the sealed cabin being further provided with an emergency treatment device for leakage; The multi-stage filter membrane switching device comprises a pneumatic push rod, two trays being arranged on the pneumatic push rod in a vertical mode, the multi-stage filter membrane switching device further comprising PTFE filter membranes and nylon screen meshes arranged on the two trays respectively, the integrated heating plate being divided into at least three ceramic heating plates, the integrated heating plate being electrically connected with the temperature control unit, the temperature control unit comprising a PID controller, a solid-state relay, a touch screen and a K-type thermocouple temperature sensor arranged in the acid-resistant cavity; The temperature control unit is provided with a segmented temperature rising program: The first stage is 120 DEG C pre-digestion for 20 min; The second stage is 240 DEG C constant temperature for 40 min; The third stage is 250 DEG C maintenance for 10 min; A conveying belt is arranged between the vacuum drying bin and the grinding bin, the vacuum drying bin is provided with an infrared radiation heating device and a vacuum pump, the acid-resistant cavity is further provided with a multi-channel liquid distributor, an electric conductivity sensor and a weighing device, the acid-resistant cavity is provided with an eddy current stirrer, the emergency treatment device for leakage comprises an HF concentration sensor arranged in the sealed cabin, a neutralizing agent spraying device, the detection threshold of the HF concentration sensor is set to be 0.5ppm, and the sealed cabin is further provided with a pressure sensor and a pressure relief valve.

2. A method for the pre-treatment of a sample for the detection of free silicon dioxide, based on the pre-treatment device for the detection of free silicon dioxide according to claim 1, characterized in that The application further discloses a sample pretreatment method, which comprises the following steps: A sample pretreatment step: a collected sample is put into the grinding bin through the sample inlet, the ultrasonic oscillator and the air flow circulating device are started to crush, then the crushed sample is transferred to the vacuum drying bin through the conveying belt, and the infrared radiation heating and the vacuum pump are started to dry; A digestion and filtration step: the dried sample is injected into the acid-resistant cavity, pyrophosphoric acid solution is added from the pyrophosphoric acid inlet according to a 1:10 ratio, the integrated heating plate is controlled through the segmented temperature rising program arranged in the temperature control unit to perform three-stage heating, meanwhile, the eddy current stirrer is started, after digestion is completed, the negative pressure adsorption device is triggered, meanwhile, the PTFE filter membrane with a filter hole diameter of 0.45mu m is pushed to a working position to perform filtration, and waste liquid is discharged into an acid-resistant waste liquid tank; A washing and drying step: the multi-channel liquid distributor is used to sequentially inject hot water with a temperature of 80 DEG C, dilute hydrochloric acid and deionized water to perform washing, the electric conductivity sensor is used to monitor the electric conductivity of the washing liquid in real time, the washing is stopped after reaching the standard, then the washed residue is transferred to the vacuum drying bin to perform synchronous infrared radiation and vacuum dehydration operation, and the weighing module automatically records the mass of the residue. Safety HF treatment step: If total silicon detection is required, the sample is transferred to a sealed HF chamber. A quantitative pump injects HF at a rate of 1 mL / min with a concentration of 40%. A pressure sensor monitors the pressure in the chamber. If the pressure exceeds a certain limit, a pressure relief valve is triggered. When the HF concentration sensor detects a value > 0.5 ppm, a neutralizer spray device is activated within 0.2 s. A negative pressure suction system recovers gaseous HF into an alkaline neutralization tank.

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