Process Control in Bleaching
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This document outlines various quality and process control parameters that should be checked during bleaching (chemicking/peroxide) in wet processing. Key parameters include checking for metal contamination in stock solutions weekly and taking necessary actions like adding sequestering agents. Other parameters that are checked once a shift include recipe, concentration of chemicals, quantity of stock solution, temperature, pH, time, and concentration of drain liquor to ensure standards are met and corrective actions are taken when needed. The ratio of Na2O to SiO2 in sodium silicate is also checked to maintain a ratio of 1:1 prior to stock preparation.
Process Control in Bleaching
- 1. QUALITY & PROCESS CONTROL IN WET PROCESSING PROCESS CONTROL IN BLEACHING (CHEMICKING/PEROXIDE)
- 2. BLEACHING
- 3. • Metal contamination Parameter • Check stock solution Check Point • Laboratory analysis Method of Checking • No metal contamination • Once a week Standard/ Frequency of Checking • Add sequestering agent • Use filters • Replace silicate by metasilicate Necessary Action
- 4. • Recipe Parameter • Prior to bleaching Check Point • Check requisition slip Method of Checking • As per quality • Once a shift Standard/ Frequency of Checking • Take corrective measures Necessary Action
- 6. • Concentration of chemicals Parameter • During scouring Check Point • Titration Method of Checking • As per requirement • Once a shift Standard/ Frequency of Checking • Adjust concentration of chemicals Necessary Action
- 7. • Quantity of stock solution Parameter • Prior to bleaching Check Point • Comparison of level of stock and quantity of cloth Method of Checking • Full consumption of stock • Once a shift Standard/ Frequency of Checking • Ensure full consumption Necessary Action
- 8. • Temperature Parameter • During Process Check Point • Thermometer Method of Checking • As per quality • Once a shift Standard/ Frequency of Checking • Regulate steam supply Necessary Action
- 9. • pH Parameter • During Process Check Point • pH paper • pH indicator Method of Checking • 9.5-10.5 (Chemick) • 10.5-11.5 (Peroxide) Standard/ Frequency of Checking • Maintain required pH Necessary Action
- 10. • Time Parameter • During Process Check Point • Dwell Time record Method of Checking • As per quality • Once a shift Standard/ Frequency of Checking • Give optimum dwell time for treatment Necessary Action
- 11. • Concentration of drain liquor Parameter • After bleaching Check Point • Titration Method of Checking • Once a day Standard/ Frequency of Checking • Ensure optimum utilization of bleach Necessary Action
- 12. • Na2O:SiO2 ratio for sodium silicate Parameter • Prior to preparation of stock Check Point • Laboratory analysis Method of Checking • Na2O:SiO2 1:1 Standard/ Frequency of Checking • Maintain the ratio with metasilicate and soda ash Necessary Action
- 13. C R Madhu Textile Processing Technology R C Technical Institute Ahmedabad, Gujarat crm4chemistry@gmail.com https://textilechemrose.blogspot .com/ THANK YOU