The production of activated carbon by chemical activation method refers to the production method of activating activated carbon by impregnation raw materials such as wood chips with zinc chloride and other solutions. This is the commonly used production method of activated carbon, which has certain requirements on raw materials so that the activator can play a role. Therefore, when using this method to produce activated carbon, plant raw materials such as wood chips are often directly used.
Zinc chloride and phosphoric acid are commonly used activators. In addition, potassium sulfide, potassium sulfate, potassium hydroxide, calcium chloride, calcium oxide, sulfuric acid and so on have certain activation effect. Zinc chloride and other chemical agents play a role in the activation process, such as swelling, catalytic dehydration, aromatic condensation and skeleton pore formation. The main factors affecting activation are zinc chip ratio, raw material type, water content of raw material, sawdust granularity, activation temperature and activation time, etc. The influence rules are as follows:
⑴ Zinc chip ratio. Zinc chip ratio refers to the weight ratio of anhydrous zinc chloride to absolute raw wood chips. Zinc chip ratio has a decisive influence on the pore structure and adsorption properties of activated carbon. The pore structure of activated carbon is often adjusted by zinc chip ratio, which is the most important factor for the production of activated carbon by zinc chloride method.
⑵ The influence of raw material types. As a result of different species, wood resin content and hardness and other properties are different, thus the chemical penetration ability of wood chips have differences. Fir chips are usually the best, pine chips the next, and hard and miscellaneous chips the worst.www.activated-carbon-pellets.com
⑶ The moisture content of raw materials. The moisture content of the sawdust affects the rate of chemical penetration into the sawdust particles, thus affecting the impregnation time. When the moisture content of sawdust is more than 30%, the impregnation time is more than 8h. Generally, the moisture content of sawdust should not exceed 5%. According to the different production technology, the moisture content of sawdust has different specific indexes.
(4) the influence of wood particle size. When the particle size of wood chips in the production of powdered activated carbon is 6~40 mesh, the particle size of wood chips has no obvious effect on the product quality. The effect of sawdust particle size on product quality is related to the zinc chip ratio used. When the zinc chips are relatively small (such as 80%), the wear resistance and relative density of activated carbon decrease with the increase of sawdust size. When the size of zinc chip is large (e.g. 200%), the wood chip particle size is 0.25~2.0mm, and the wear resistance and relative density of activated carbon are not significantly affectedcoconut activated carbon factory