Preparation process of medicinal sodium chloride is as follows:
1, dissolution: dissolve the crude salt in water and prepare saturated brine.
2, precipitation: to the saturated brine add a slight excess of barium chloride solution, the sulfate ions into barium sulfate precipitate, removed by filtration.
3, filtration: the precipitate produced in the previous step is filtered off to obtain a clarified filtrate.
4, evaporation: the filtrate will be heated and evaporated, concentrated to a thick paste.
5, crystallization: continue to heat and evaporation, so that the sodium chloride crystal precipitation.
6, separation: precipitation of sodium chloride crystals and mother liquor separation, get pure medicinal sodium chloride.
7, washing: washing sodium chloride crystals with medicinal ethanol to remove impurities attached to the surface.
8, drying: the washed sodium chloride crystals are dried in the oven to get the final medicinal sodium chloride product.
Precautions for chemical experiments:
1, before the experiment, you must study the content of the experiment, understand the purpose of the experiment, the experimental principles and experimental steps, and make clear the risk factors and safety measures in the experiment.
2, into the laboratory must be in accordance with the provisions of the lab coat, is strictly prohibited to wear slippers, shorts and skirts and other clothing not suitable for laboratory wear.
3, a variety of instruments and equipment in the laboratory must be used in accordance with the provisions of the private demolition, modification or misappropriation is strictly prohibited.
4, the laboratory is strictly prohibited smoking, eating and storing items unrelated to the experiment.
5, the laboratory should be kept quiet, it is strictly prohibited loud noise and fighting.
6, the experimental process must strictly abide by the experimental steps and operating practices, is strictly prohibited to change the experimental conditions and operating methods.
7, the experimental process should pay attention to the observation of experimental phenomena and data recording, timely analysis and processing of experimental data.
8, after the experiment to clean up the experimental site in a timely manner, the instrumentation to the position, clean up the experimental waste and garbage.
9, the experiment if encountered abnormalities or accidents, should immediately stop the experiment and report to the laboratory manager or teacher.
10, after the end of the experiment to seriously summarize the experimental process and results, write a laboratory report and submit it on time.
11, chemical reagents in the laboratory must be categorized and stored, is strictly prohibited to mix and put. Flammable, explosive, toxic and hazardous reagents must be stored and used according to regulations.
12, the laboratory is strictly prohibited the use of open flames, such as heating must be used to use electric heating equipment, is strictly prohibited the use of open flame heating.
13, the experimental process should pay attention to personal protection, such as wearing protective glasses, gloves, lab coats.