Method for Removing Contaminants from Laboratory Magnetic Stirred Reactors (Part 3)

　　Previously, the editor briefly described several methods for removing long-term contaminants adhering to the inner walls of magnetic stirrer reactors used in laboratories. Now, continuing from the previous discussion, let’s talk about acid pickling, solvent-based removal, and ultrasonic cleaning.

　　1. Acid Pickling Method: This method is primarily used to remove corrosive substances from the inner walls of magnetic stirring reactors. In the acid pickling process, special attention must be paid to the fact that acid pickling can induce hydrogen embrittlement in materials such as austenitic stainless steel. Therefore, immediately after acid pickling, a dehydrogenation treatment must be carried out—specifically, baking at around 200°C for 3 hours. It is also crucial to control the duration of the acid pickling process to prevent excessive corrosion of the reactor walls. After acid pickling, a neutralization treatment should be performed, followed by thorough rinsing under running water.

　　II. Solvent Removal Method: This method typically employs solvents such as alcohol, acetone, gasoline, trichloroethylene, and others to remove stubborn grease, oil films, waxes, adhesives, paints, and certain common organic contaminants. However, the solvent removal method is not suitable for removing rust, oxide scales, or other inorganic substances. For magnetic reactors made of titanium and titanium alloys, special attention must be paid to the halogen content in the solvents to prevent corrosion during use; ideally, the halogen content should be below 1%.

　　3. Ultrasonic Cleaning Method: Ultrasonic cleaning leverages the powerful penetrating ability of ultrasonic mechanical vibrations to remove contaminants such as oil stains from inside magnetic stirring reactors. This method is often used in conjunction with solvents, which can enhance its effectiveness and reduce cleaning time. When employing this method, it’s important to ensure that the components being cleaned are fully immersed in the ultrasonic cleaning tank. This approach is particularly well-suited for magnetic stirring reactors with smaller volumes.