Methods for sorting materials

摘要

Disclosed herein is the use of differences in x-ray linear absorption coefficients to process ore and remove elements with higher atomic number from elements with lower atomic numbers. Use of this dry method at the mine reduces pollution and transportation costs. One example of said invention is the ejection of inclusions with sulfur, silicates, mercury, arsenic and radioactive elements from coal. This reduces the amount and toxicity of coal ash. It also reduces air emissions and the energy required to clean stack gases from coal combustion. Removal of said ejected elements improves thermal efficiency and reduces the pollution and carbon footprint for electrical production. 100 Providing sample 102 Sizing sample 104 Irradiating thickest piece of sample 106 Determining ejection threshold 108 Sample entering sensing region 110 Measuring x-ray transmission 112 Determining whether ejection threshold is reached 114 If yes, ejecting sample 116 If no, then no ejecting Figure 1