“Hand sort” (considered “direct shipping ore (DSO)”) in Mexico is typically oxide ore (the mineral is senarmontite or valentinite) that has been upgraded by hand sorting to a grade of 30-60% contained antimony. Alternatively it can be sulfide ore (the mineral is stibnite) that has been upgraded by hand sorting to 30-60% contained antimony. Hand sot is typically a mixture of sulfide and oxide minerals from Mexico
“Sulfide concentrates” are usually flotation concentrates produced in a mill that will range from 50-68% contained antimony. The mineral is usually stibnite and the theoretical maximum antimony content is 71.1%. Recoveries from sulfide mills are generally 80-95%.
“Oxide concentrates” are produced using gravimetric concentrators such as jigs, tables, and spirals. They are generally either senarmontite and/or valentinite that are both antimony trioxide with a theoretical maximum antimony content of 83.53%. Gravity concentrates are typically much lower grade than sulfide concentrates and are in the 25-40% antimony content. Recoveries from oxide mills are generally less than 50%.
“Crude” means crude antimony trioxide, typically 82-82.5% antimony metal contained. The desirable mineral is senarmontite. This can be refumed directly to “finished” or converted to metal, or sold directly as a feed for other plants. It is typically an off-white color (gray or light brown).
“Finished” means finished antimony trioxide. It typically is senarmontite and has an antimony content of 82.5 –83.3%. It is brilliant white.
“Fuming” refers to the process of fuming hand sort, oxide concentrates, sulfide concentrates, or crude to either crude or finished.
“Reduction” refers to reducing oxide hand sort, sodium antimonite or crude to metal. Carbon is generally used.