In modern gold mines, activated carbon has become an irreplaceable gold catcher. This seemingly ordinary black material plays a core role in the cyanidation gold extraction process.

The secret lies in its unique physical structure. The specific surface area of high-quality coconut shell activated carbon is amazing. The surface area of each gram of activated carbon is equivalent to the size of a football field, reaching 1000-1500 square meters. This maze-like structure composed of micropores and mesopores provides a perfect trap for capturing gold cyanide complexes.

When the gold-containing ore is crushed to a fineness of about 300 meshes and sodium cyanide solution is added to form a slurry, the gold begins to dissolve and form a gold cyanide complex [Au(CN)₂]⁻. At this time, the huge surface area of the activated carbon begins to play a role, and its hydrophobic pore wall has a special affinity with the gold complex, which can efficiently adsorb gold molecules.

"The surface of activated carbon contains a variety of functional groups, such as carboxyl, hydroxyl, phenol, etc. These chemical structures enhance its selective adsorption ability. "Professor Li, a materials science expert, explained, "Especially for gold-cyanide complexes, activated carbon shows much higher selectivity than other metals."

This selectivity is crucial. In a complex slurry environment, where multiple metal ions such as copper, iron, and zinc coexist, activated carbon can accurately identify and preferentially adsorb gold molecules, greatly improving the purity of subsequent refining.