Manufacturing method of chromic anhydride
I. INTRODUCTION
Chromic anhydride is an important inorganic chemical, which is widely used in the fields of oxidizers, catalysts, pigments, electroplating, pharmaceuticals and so on. Therefore, it is of great significance to study its manufacturing method to improve the production efficiency, reduce the cost and improve the product quality. In this paper, we will introduce the manufacturing method of chromic anhydride, including raw material preparation, reaction process, post-treatment and so on.
II. Raw material preparation
1. Chrome ore: the main raw material of chromic anhydride is chromite, whose main component is chromite (FeCr2O4), and also contains some impurities such as silicon, aluminum, calcium, magnesium and so on.
2. Sulfuric acid: used as oxidizing agent and reaction medium.
3. Reaction process
The manufacturing process of chromic anhydride mainly consists of the following steps:
1. Roasting: Chromite is roasted to a certain temperature to decompose it into chromium oxide.
2. Leaching: The roasted chrome ore is leached with sulfuric acid to produce chromic sulfuric acid and ferrous sulfate, etc.
3. Oxidation: Oxidize the chromic sulfuric acid in the leaching solution to chromic acid with an oxidizing agent (e.g., nitric acid).
4. Crystallization: The oxidized solution is cooled and crystallized to obtain chromic anhydride crystals.
4. Post-treatment
1. Centrifugal separation: the mother liquor and chromic anhydride crystals after crystallization are separated by centrifugation to get the purer chromic anhydride crystals.
2. Drying: The centrifugally separated chromic anhydride crystals are dried to obtain the final chromic anhydride product.
V. Precautions
1. During the roasting process, the temperature and time need to be controlled so as not to cause incomplete chromite decomposition due to excessive roasting.
2. In the leaching process, the concentration of sulfuric acid and leaching time need to be controlled to improve the leaching rate of chromium.
3. In the oxidation process, it is necessary to choose suitable oxidizer and oxidation conditions to ensure the complete oxidation of chromium sulfate.
4. In the crystallization process, cooling rate and crystallization time need to be controlled to obtain larger crystals and higher yields.
VI.CONCLUSION
The manufacturing method of chromic anhydride includes raw material preparation, reaction process and post-treatment, etc. The process parameters of each step need to be controlled to ensure the quality and yield of the product. Meanwhile, it is also necessary to pay attention to the safety and environmental protection aspects to ensure the smooth progress of the production process.
