Method of magnetic separation and apparatus therefore

A method of dry magnetic separation for separating materials of different types and levels of magnetism from a raw sample containing particulate material having a range of magnetic susceptibilities, said sample including a feebly magnetic fraction and a strongly magnetic fraction, comprising the steps of:

• a. processing said raw sample through a first dry magnetic separation pass to remove substantially all of said strongly magnetic fraction from said raw sample, thereby separating said strongly magnetic fraction from said feebly magnetic fraction;
• b. processing said feebly magnetic fraction through a second dry magnetic separation pass including a magnetic separator means and a splitter means, thereby separating said particulate material into at least three different magnetic susceptibility fractions, each said fraction exhibiting a range of magnetic susceptibilities, which range is different from each other said range of magnetic susceptibilities of each said other fraction, and thereby producing a spectrum of separate refined particle samples comprising each said fraction;
• c. collecting said refined particle samples comprising each said fraction;
• d. measuring the magnetic susceptibility range of magnetic susceptibilities of each said fraction collected;
• e. correlating said magnetic susceptibility range of at least one said collected fraction with at least one identifying physical and/or at least one chemical characteristic of said collected fraction in order to determine which fraction or fractions are to be recovered for further processing;
• and
• f. processing said recovered fraction or fractions through at least one additional dry magnetic separation pass including a magnetic separator means and a splitter means, thereby separating said fraction or fractions into at least two different magnetic susceptibility fractions, including a clean fraction and a refuse fraction, said clean fraction having a magnetic susceptibility correlating with said identifying physical and/or chemical characteristics.