Curvilinear surface classification of feed stock

A method for air classification of a milled feed stock, the method comprising:

• generating a feed stream by combining the milled feed stock with at least one gasflow element, wherein the milled feed stock includes a plurality of particles, each of the plurality of particles having varying particle sizes and constituent elements including at least one of:
• a first physical characteristic and a second physical characteristic different from the first physical characteristic;
• generating an electrically charged milled feed by applying an electrical charge to the milled feed within the feed stream;
• generating an electrostatic field in relation to the curvilinear surface;
• directing the electrically charged milled feed across the curvilinear surface, such that the milled feed stock in the feed stream separates into a plurality of classification streams based on the constituent elements and particle sizes of the milled feed stock;
• separating the plurality of classification streams based on the electrically charged milled feed stock interacting with the electrostatic field and based on the particles sizes and the constituent elements;
• and
• collecting each of the plurality of classification streams, thereby classifying the milled feed stock contained therein based at least on the constituent elements for each of the plurality of classification streams.