Wood is the raw material for making wood activated carbon. It can be used for industrial decolorization after processing such as treatment, carbonization, activation, zinc chloride recovery, rinsing, centrifugal dehydration, dryness, destruction, packaging and other processes. However, there are testing standards for wooden activated carbon, which need to be tested according to the national standard GB / T13803.2-1999. The following editors will introduce them in detail.
1. Treatment of wood chips
Sift the wood chips to separate the wood flowers and metal impurities, and then dry them. The water content is 30%. Every 75 kilograms of wood chips were mixed with 225 kilograms of zinc chloride solution with a concentration of 50 Baume. After 5 hours, they were mixed once and allowed to stand for 10 hours before carbonization.
Put the treated wood chips that have been left for more than 10 hours in an open flat bottom carbonization furnace, heat it for carbonization and continue to mix (do not make the furnace bottom wood chips into thick pieces), about 1 hour, the wood chips will all turn black (temperature 300-400 ℃, carbonization At the end, you should participate in the activation furnace as soon as possible to prevent the absorption of water from burning at high temperatures.
Place the carbonized shavings in a high temperature activation furnace (furnace temperature above 700 ℃), and evenly remix every 15 minutes. When the carbon in the activation furnace is all brown (temperature 650-700 ℃ for about 2 hours), the activation is completed.
After the activation is completed, push it into the storage room and take it out after the temperature drops. When remixing and firing, the action must be agile to reduce the time when the carbon is in contact with the air at high temperature, which can not only prevent burning, maintain the furnace temperature, but also reduce ZnCL2 escape.
4. Recovery of zinc chloride
The activated charcoal is taken into the washing machine and rinsed with 25-30 Baume degree zinc chloride solution. The washed 50 Baume degree zinc chloride solution is reserved for the next treatment of wood chips. Then continue to rinse with low-concentration zinc chloride solution until the washing liquid reaches 1 Baume degree, the recovery operation is completed.
Put the charcoal after the recovery of zinc chloride into the tank, take 3% hydrochloric acid (relatively dry carbon content), add water, and heat it with steam. The washing liquid is used for recovering zinc chloride, and rinsed continuously with clean water until there is no white deposit in the sodium carbonate test solution.
6. Centrifugal dehydration, dryness, destruction, packaging
Dry the rinsed charcoal with a centrifuge (water content is 30%). Do not over-dry to prevent burning or flying.
1. Activated carbon is supervised by the Ministry of Health and Food Epidemic Prevention and Health Supervision Department, and there are also certain promulgated standards. Generally, the standard of food grade wood activated carbon is: ash 4-6%, iron salt: 0.02-0.05, 0.08-0.1 coal quality 12-15%.
2. These standards determine the price of these activated carbons. These are in accordance with the provisions of the national standard GB / T13803.2-1999, national standard GB / T12496-1999, national standard GB / T7702-1997.
The above is a detailed explanation of "Wooden activated carbon production process and testing standards", if you want to know more, please consult us ~