公害防止用球形活性炭の石炭を原料とした製造法

Abstract

There are growing markets for activated carbon for such purposes as water treatment and air pollution control. Although these new markets are not developing as fast as expected, the ultimate potential is considered to be huge. Therefore, intensive research is being conducted in the field of production of activated carbon to develop a new manufacturing process or to seek new kinds of raw materials. Under these circumstances we have developed the new manufacturing technique for the production of spherical activated carbon from coal, which may be promising as effective adsorbents for pollution control.The manufacturing process of the activated carbon from coal consists of five steps. They are pulverizing of coal, pelletizing of fine coal, precarbonization, carbonization and steam activation. The choice of raw coal species is very important to produce good spherical activated carbon. Coking-coal with a carbon content of 80-85% has proven to be a good raw material. After pulverizing, the coal is pelletized into spherical particles with a disk-type pelletizer. In this process, particle size distribution of the fine coal, water content, kind and amount of binder added all influence the pelletizing effect. To obtain strong and dense spherical carbon, carbonization is carried out at a temperature of 500-600°C at heating rate of 0.5-5°C/min. It appeared that an indirectly heated rotary kiln is the most suitable carbonization apparatus. The carbonized pellets are activated with steam. Spherical activated carbon exhibiting a high adsorption property and strength can be prepared with an indirectly heated rotary kiln or directly fired rotary kiln in the presence of limited quantities of oxygen.