The application of ozone in pulp bleaching in paper mills

The amount of ozone used for pulp bleaching is influenced by various factors, such as pulp type, pulp concentration, bleaching process, etc.
Generally speaking, the amount of ozone used for pulp bleaching is usually between 0.5% and 3%. However, the specific optimal dosage needs to be adjusted and optimized according to the actual situation.
When determining the amount of ozone, it is necessary to comprehensively consider factors such as bleaching effect, pulp quality, and cost. A higher amount of ozone may improve the bleaching effect, but it may also lead to a decrease in pulp strength or other quality issues. Meanwhile, excessive use of ozone can also increase costs.
Therefore, in practical applications, it is recommended to conduct laboratory or pilot tests to determine the optimal ozone dosage under specific pulp and bleaching conditions. In addition, relevant research literature and empirical data can be referred to, and adjustments can be made based on the requirements of the production process.

Here are some methods to reduce the impact of ozone on pulp strength:

1. Optimize bleaching process parameters, including controlling the amount of ozone, reaction time, temperature, and pH value. By precisely adjusting these parameters, it is possible to reduce damage to pulp strength while ensuring a certain bleaching effect.
2. Pre treatment: Before ozone bleaching, the pulp is subjected to appropriate pre-treatment, such as alkaline treatment or adding protective agents. Protectants can react with the components in pulp to form a stable structure, thereby reducing the attack of ozone on fibers.
3. Segmented bleaching: Divide the bleaching process into multiple stages and use other mild bleaching agents (such as hydrogen peroxide) in conjunction with ozone to reduce the intensity of ozone alone.
4. Improving pulp raw materials: Select appropriate raw materials or pretreat them to improve their fiber structure and chemical composition, thereby enhancing the tolerance of pulp to ozone bleaching.
5. Strengthen subsequent treatment: After ozone bleaching, appropriate post-treatment steps such as fiber swelling and crosslinking between fibers are carried out to restore and enhance the strength performance of the pulp.
6. Optimize equipment and process conditions: Ensure uniform contact and reaction between ozone and pulp, avoid local overreaction, and thus reduce the uneven impact on pulp strength.
7. Using new additives: Research and apply new chemical additives that can protect fiber structure and chemical bonds during ozone bleaching, and maintain pulp strength.

It should be noted that the specific method should be comprehensively considered and optimized based on factors such as the type of pulp, quality requirements, and production conditions.