日本东北地区岩手县产的粘土,作为耐火粘土用,其中含有的铁大部分是菱铁矿、对这种菱铁矿用高梯度磁选的方法除去,过去已有研究报告,本文介绍的粘土是这种粘土下部的含铁高的硬质粘土,据估计岩手具有500万吨左右,供试验用的三种试样分别 Clay produced in Iwate prefecture of northeastern Japan is used as refractory clay and most of the iron contained therein is siderite. This siderite is removed by high gradient magnetic separation. In the past, there have been reports that the clay Is the hard clay with high iron content in the lower part of the clay. It is estimated that Iwate has a volume of about 5 million tons and the three samples for testing