How to distinguish between regenerated activated carbon and primary activated carbon

Generally speaking, both granular activated carbon and powdered activated carbon can be regenerated, and the regeneration of powdered activated carbon is more common. The good adsorption kinetics of powdered activated carbon and the high medium and large pore distribution of wood powdered activated carbon lead to excellent decolorization performance, which leads to the wide application of powdered activated carbon in food and chemical decolorization, and its relative proportion and absolute number of use are very large. In addition, the large number of powdered activated carbon users per user is also very advantageous and attractive in terms of the quality control of raw materials for activated carbon regeneration. The market scale of powdered activated carbon is large, so the sales process and results of its regenerated carbon are relatively easy to control. It is very difficult to distinguish whether powdered activated carbon is regenerated.

Granular activated carbon is mainly divided into coal-based activated carbon and fruit shell activated carbon (fruit shell activated carbon also includes coconut shell activated carbon) according to the material. Coal-based activated carbon has lower strength than fruit shell carbon, and the loss of regeneration will be greater than that of fruit shell carbon. Since the domestic coal-based granular activated carbon market is mainly based on low indicators (800 iodine value and below), the price of native activated carbon is not high, which limits the sales target price of regenerated activated carbon. At the same time, the regenerated activated carbon needs to bear the logistics cost of recycling the waste activated carbon. Therefore, the target customers of the coal-based activated carbon regeneration plant are generally users whose waste activated carbon is classified as hazardous waste activated carbon. The regeneration of hazardous waste activated carbon requires a government license, and the hazardous waste treatment fee can be added when selling the regeneration service, so that the regeneration of coal-based activated carbon is profitable. Therefore, the probability of using regenerated coal-based activated carbon (including coal-based columnar activated carbon) to impersonate original coal-based activated carbon is relatively small.

Fruit shell activated carbon is mostly used for water treatment. It has high strength, is easy to regenerate, and has low regeneration loss. The iodine value of fruit shell activated carbon (including coconut shell activated carbon) used for water treatment decreases less after use (the iodine value decrease is common within 100-200), and it does not belong to hazardous solid waste. The regeneration plant does not need a hazardous waste treatment license; the regeneration takes a short furnace time, the factory has a large regeneration capacity, and the supply chain end cost is low. On the other hand, the unit price of fruit shell carbon is relatively high, especially coconut shell activated carbon. The difference in its adsorption capacity is difficult to directly judge by senses (powdered activated carbon can be intuitively compared with the dosage of added activated carbon and the decolorization effect), and can only rely on laboratory testing. Therefore, the current situation in the industry is that cases of fruit shell charcoal (including coconut shell charcoal) using regenerated charcoal as primary charcoal have occurred from time to time, including our colleagues who are professionally engaged in activated carbon have also been deceived.

Since the original use of regenerated powdered activated carbon is the same as the use after regeneration, assuming that they are both in the food industry, it does not matter whether the purchased activated carbon is regenerated or not, as long as the decolorization and purification effect is good. However, in the water treatment industry, if the fruit shell activated carbon is regenerated carbon and the primary charcoal is from a cost perspective, the former is a huge profit. For sellers, if they do not tell the buyer honestly, it is a very serious moral risk.

Solving the problem of whether the purchased fruit shell charcoal is primary charcoal from a technical perspective is putting the cart before the horse. To truly solve this problem, people can be trusted, and finding the right partner is the right way. So is there a technical solution to distinguish whether fruit shell charcoal is regenerated charcoal? Let's talk about it briefly.

First, due to the high strength of fruit shell charcoal, the edges and corners of primary fruit shell charcoal are relatively sharp, forming sharp angles or sharp flakes; after half a year or even a year of use, the impact of water flow will wear its edges and corners of regenerated fruit shell charcoal, and the edges and corners are relatively rounded.

Second, since fruit shell charcoal is mostly used for water treatment, it will be used for a long time, and calcium and magnesium elements will be deposited inside the activated carbon, increasing the ash content of the activated carbon. Usually, the ash content of coconut shell charcoal is about 3-4%, and the ash content of coconut shell charcoal that has been acid-washed or water-washed is even lower at 1-2%; the ash content of used coconut shell charcoal will definitely be higher, but how much higher it is depends on its original use. Since the deposits of calcium and magnesium ions are mostly soluble in acid, first put the activated carbon to be tested into a glass column, soak it for 24 hours, and then rinse it with water 10-20 times the volume of the activated carbon, and then test the acid-soluble ash content of the washed activated carbon and compare it with the standard sample. You may get a better reference result.

Third, the higher the road, the higher the devil. Some merchants mix recycled fruit shell charcoal with native fruit shell charcoal. For example, the proportion of the former is only 10-30%, and it is difficult for users to distinguish them using the methods of the first and second points above. So in the end, it depends on the person. Finding the right person to do business is the way to make money.