Commercial sources for uranium recovering mainly come from phosphate rock deposits such as the monazite sands. Monazite is the leading source of uranium, along with pitchblende and lignite. Uranium is first collected through either open pit or underground extraction, or through leaching or borehole mining. Most of the uranium ores contain very low amounts of uranium, less than one percent, and the extraction and isolation process is highly complex. First the ores are crushed into a fine powder, then an acid or alkali substance is leached into the powder. This solution is treated to precipitation, solvent extraction, and ion exchange to form ‘yellowcake.’ The cake like product is over ¾ uranium, and it is calcined in order to remove the remaining contaminants. Uranium can also be produced using a variety of methods including: electrolysis of potassium, uranium, fluoride compound, the thermal decomposition of uranium halides, and the reduction of uranium halides with alkaline materials.