Cobalt blue is an inorganic pigment with a distinctive blue color that is widely used in the production of chemicals such as ceramics, glass, plastics and coatings. The manufacturing method of cobalt blue mainly involves chemical reactions and heat treatment processes to ensure that the pigment has high color stability and weather resistance. This article will introduce the manufacturing method of cobalt blue in detail, including raw material preparation, synthesis reaction, post-treatment and product testing.
I. Raw material preparation
The raw materials required for manufacturing cobalt blue mainly include cobalt oxide, aluminum oxide and alkali metal salt. Among them, cobalt oxide is the main source to provide cobalt ions, alumina is used to form the matrix of pigment particles, and alkali metal salt plays the role of flux. In order to ensure the quality and stability of the product, it is necessary to use high purity raw materials and conduct strict quality inspection.
II. Synthesis reaction
The synthesis reaction of cobalt blue usually adopts high temperature solid phase method. The specific steps are as follows:
1. Mix cobalt oxide, alumina and alkali metal salt according to a certain proportion to get the precursor mixture.
2. The precursor mixture is placed in a high-temperature furnace and roasted at a certain temperature. During the roasting process, a chemical reaction occurs between the raw materials to produce cobalt blue pigment.
3. After the roasting is completed, it is naturally cooled to room temperature to obtain the crude cobalt blue pigment.
3. Post-treatment
In order to obtain high quality cobalt blue pigment, it is necessary to post-treat the crude product. Post-treatment mainly includes grinding, grading and washing steps.
1. Grinding: Put the cobalt blue pigment crude product into the grinder, add appropriate amount of grinding medium and water, and grind it. Through grinding, the particle size of the pigment particles can be reduced, and the dispersibility and coloring power of the pigment can be improved.
2. Classification: After grinding, the pigment particles with different particle sizes are separated by classification equipment to obtain cobalt blue pigment with uniform particle size distribution.
3. Washing: The cobalt blue pigment after grading is washed with deionized water to remove the impurity ions on the surface and the grinding medium, so as to get the pure cobalt blue pigment. IV. Product testing
In order to ensure the quality of cobalt blue pigment, it is necessary to carry out strict testing on the products. The testing items include pigment color, weather resistance, chemical resistance, thermal stability and so on. By comparing the national standards or customer requirements, we can judge whether the products are qualified or not. For unqualified products, rework or adjustment of process parameters are needed to ensure product quality.
V. Precautions
1. In the process of raw material preparation, high purity raw materials should be used to avoid the introduction of impurity ions, which will affect product quality.
2. In the process of synthesis reaction, the roasting temperature and time need to be strictly controlled to ensure that the reaction generates cobalt blue pigment. At the same time, attention should be paid to the control of the atmosphere in the furnace to prevent the pigment from being oxidized or reduced.
3. In the post-treatment process, suitable grinding media and grinding conditions should be selected to obtain ideal particle size distribution of pigment particles. Meanwhile, the pH value of the washing water and the number of washing times need to be paid attention to ensure the purity of the pigment.
4. In the process of product testing, standard testing methods and instruments should be used to ensure the accuracy and reliability of the test results.
In conclusion, the manufacturing method of cobalt blue involves several links, and requires strict control of each process parameter to ensure product quality. By optimizing the process conditions and improving the degree of equipment automation, the production efficiency and cost reduction of cobalt blue can be further improved to provide high-quality pigment raw materials for chemical production.
