Perchloric Acid Fume Hood

CIRCULATING WATER DILUTION SYSTEM

In the experiments carried out in perchloric acid fume hoods, there may be an aerosol release process of perchloric acid, so the fume hood needs to be ventilated under the conditions of rated high air volume exhaust, with a design value of 1300 CMH, perchloric acid and ventilation. The alkaline water after the deflector of the cabinet is mixed and contacted, and the chemical reaction is:

HClO4+NaOH====NaClO4+H2O

The neutralized product is a neutral product with a pH of 7-14, so the designed recycling system is made of chemically resistant materials.

A buffer tank is arranged at a lower part of the fume hood, and a PP water pump is connected to the outlet side, and the water pump is connected with the atomization pipe behind the baffle, and the water pump outputs the alkali liquid to the atomization tube in the form of medium pressure, and forms a fine water droplet after passing through the atomization tube. The gas is mixed with the perchloric acid gas to complete the chemical reaction. The product is recirculated into the buffer tank of the water pump through the technical interlayer by the gravity.

OPERATION PROCESS

The system needs to be pre-checked before use, including the following:

1) The water tank should be filled with alkaline water (NAOH 50% solution), and tested with PH reagent, and the PH value recorded.

2) Check that all valves in the circulating water system are all open. If the valve in the circulating system of the pump is closed, the circulating pump must not be started.

3) Whether the test of perchloric acid is prepared in the fume hood, the fume hood needs to have the rated exhaust air volume (the average surface wind speed is between 0.5-0.8m/s, which needs to be detected by hand-held anemometer)

4) Turn on the pump start button, at which point the circulating water is evenly distributed in the form of water droplets behind the deflector.

System operation flow after the experiment is completed

1) The perchloric acid experiment in the fume hood has been completed

2) Turn off the water pump and test with PH test paper, and record the PH value for the reference value of the next experiment. (When the pH is below 6, the buffer needs to be replaced)

3) Close the valve on the water system

4) Turn off the exhaust of the fume hood

PROTECTION& TREATMENT

Operational precautions: closed operation, local exhaust. The operation is as mechanized and automated as possible. Operators must be specially trained to strictly follow the operating procedures. Operators are advised to wear a filter-type gas mask (full face mask) or self-contained breathing apparatus, a polyethylene protective suit, and rubber gloves. Keep away from fire, heat, and smoking in the workplace. Prevent vapors from leaking into the workplace air. Avoid contact with acids, bases, and amines. Pay particular attention to avoid contact with water. Lightly load and unload during handling to prevent damage to packaging and containers. Vibration, impact and friction are prohibited. Equipped with the corresponding variety and quantity of fire-fighting equipment and leakage emergency treatment equipment. Empty containers may be harmful residues. When diluting or preparing the solution, the acid should be added to the water to avoid boiling and splashing.

PRECAUTIONS

This type of fume hood is a special type of fume hood for perchloric acid. Users are required to carry out experiments according to the chemical characteristics of perchloric acid. The experiment should follow the relevant experimental procedures. Do not directly carry high concentration and high dose in the fume hood. Perchloric acid experiment. The alkaline water and circulation system behind the baffle of the fume hood is a neutralization system, which is to ensure that no high concentration of perchloric acid residues are accumulated in the fume hood, causing chemical reactions such as burning, explosion or mass heating. There is no guarantee that national standards for exhaust emissions will be met. In order to meet the national environmental protection corresponding emission standards, a secondary neutralization reaction is required on the fan side.

FIRST-AID

Skin contact: Immediately remove contaminated clothing and rinse with plenty of running water for at least 15 minutes. Seek medical attention.

Eye contact: Immediately lift eyelids and rinse thoroughly with plenty of running water or saline for at least 15 minutes. Seek medical attention.

Inhalation: Remove quickly from the scene to fresh air. Keep the airway open. If breathing is difficult, give oxygen. If breathing stops, perform artificial respiration immediately. Seek medical attention.

Ingestion: Rinse mouth with water and drink milk or egg white. Seek medical attention.

MAINTENANCE

◇ If the pump leaks, please stop the experiment immediately, and contact the contractor for timely maintenance;

◇ The circulating water treatment system needs to regularly clean the sludge in the buffer tank;

◇ The pump must not be idling without liquid;

◇ The pump should not be operated when the pipeline valve is not open;

◇ The pump must not run a chemical solution with a temperature exceeding 50 °C;