The invention belongs to the field of
coal chemical industry, and more specifically relates to a preparation method of active
coke. The preparation method comprises following steps: 1, a
coal raw material is subjected to
carbonization at 400 to 700 DEG C so as to obtain semicoke, wherein
carbonization time is controlled to be 6 to 12h; 2, semicoke obtained in step 1 is smashed into particles of an appropriate particle size, wherein the particle size ranges from 1 to 20mm; 3, the
coal particles obtained via smashing are mixed with a
metal sulfide aqueous solution so as to obtain wet coal particles; 4, the wet coal particles are subjected to reaction at 100 to 250 DEG C until
drying is realized so as to obtain an activated material; 5, the activated material is sieved so as to obtain a product with a particle size
ranging from 1 to 20mm; and 6, an additive is added into the product, and
granulation is carried out so as to obtain an active
coke finished product. When the active
coke is used for treating waste water containing a relatively large amount of
heavy metals such as
electroplating waste water, the
metal sulfide in the pores of the active coke is dissolved in water, and reaction of the
metal sulfide with
heavy metals in water is realized rapidly, precipitate or floccule is generated, and the precipitate or floccule is intercepted in the pores of the active coke, so that most of the
heavy metals is removed.