The purification of Missouri fire clays

At the present time there appears to be an unlimited supply of high grade fire clay available for most any purpose. But some time in the future there will rise the problem of purifying the low grade clay to such an extent that it will be used in high grade fire clay products. Whatever purification method may be employed it must be applicable on a commercial scale and the cost of purification must be very low. Until the present time little if any work along this line has been reported. Apparently no one has ever attempted any serious efforts to purify low grade fire clay. Therefore, the field is too broad to cover in a short time. It must be developed step by It is the object of this research to pursue several possible and plausable sic methods of purification and to determine the approximate merits of each in such a manner that latter research men may know which fields show the most promise. With this object in mind we proceed --Introduction, page 2