| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a method for manufacturing artificial sand, in which artificial sand doing no harm to the environment can be manufactured in a short period of time from a dehydrated cake obtained from sludge and to provide a flocculant excellent when used in the method for manufacturing artificial sand. <P>SOLUTION: Since artificial sand is manufactured from sludge (the dehydrated cake) by using the flocculant, the elution of hexavalent chromium, which is the problem of the conventional method for producing artificial sand, does not arise from the artificial sand manufactured by this method and the environment is not harmed. Though it takes several weeks up to now to carry out all of manufacturing steps until the artificial sand having satisfactory hardness is obtained, several weeks can be shortened to half a day to several days since the flocculant having specific composition is used. As a result, the increase in the manufacturing cost to be caused by occupying a working place can be avoided. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
