Ore classification introduction

Burning

Roasting is a metallurgical process that is carried out at high temperatures, but more often even without partial melting of the phases. All processes during firing take place between solid and gaseous phases, at a temperature of 500-1000-1200 ^o C. Firing processes are divided into the following:

1. 
   Calcination firing (calcination). Its purpose is to change the chemical composition of those ore minerals that are in the raw material. Here, mainly dissociation reactions occur. Carbonates are subjected to this firing
   

CaCO3 _{_} CaO + CO ₂

Or hydroxides

Al ( OH ) ₃ Al ₂ O ₃ + 3 H ₂ O _vapor

Oxidative roasting of sulfide ores and concentrates. The goal is to convert metal sulfides into oxides

ZnS +1.5 O ₂ ZnO + SO2 _{_}

(sulfatizing firing)
ZnS + 2O ₂ ZnSO4 _{_}

1. 
   Agglomeration firing is a process in which powdered material is converted into lumps. This process is carried out due to the recrystallization of the material without the formation of a liquid phase or due to the formation of a certain amount of the liquid phase, which, when solidified, binds (glues) the powder particles into a lump product
   

2PbS + 3O ₂ + SiO ₂ PbO + PbO∙SiO ₂ + 2SO ₂

fusible

This process is used before smelting the ore in a shaft furnace.

1. 
   Reduction firing is divided into magnetizing and reduction firing.
   

1. 
   magnetizing roasting of iron ores:
   

3 Fe ₂ O ₃ + CO 2Fe ₃ O ₄ +CO ₂

This type of roasting can be used before beneficiation of iron ores in order to convert weakly magnetic compounds into highly magnetic ones ( Fe ₃ O ₄ ).

1. 
   reduction firing, e.g. UO ₃ and U ₃ O ₈ to UO ₂
   

UO ₃ + H ₂ UO2 + _{H2O _} _

1. 
   Chlorinating roasting or chlorination. Its purpose is to convert metal oxides or sulfides into chlorides.
   

ZrO ₂ + 2Cl ₂ + C ZrCl _{4 ( gas )} + CO (CO ₂ )

1. 
   Fluoridation roasting or fluoridation. Its purpose is to convert oxides into fluorides.
   

UO ₂ + 4HF UF ₄ + 2 H ₂ O