Ore classification introduction

Metallurgical melts

In these processes, liquid phases play a major role, but this is not only melting, but a complex process accompanied by numerous chemical transformations. In these processes, in general, the starting solids react with each other and with the gaseous phase, producing a sum of liquid phases and a modified gaseous phase. The resulting liquid phases have low mutual solubility and therefore separate. Metallurgical smelting is divided into ore smelting and refining smelting.

Ore smelting is one in which ore or concentrate is processed. According to the nature of the chemical reactions they occur, they are divided into the following types:

1. 
   Reduction smelting - (for example blast furnace process)
   
2. 
   

Fe ₂ O ₃ + SiO ₂ + C + CaC O ₃ → Fe _(l) + CaO ∙ SiO _{2 (l)} + CO _(gas) + CO _{2 (gas)}
ore coke fluxes slag
Cast iron and slag - two liquids that are poorly soluble in one another, are separated by density (slag up, cast iron down). Lead and tin are produced using reduction smelting.

3. 
   Oxidative concentration smelting. Its goal is not to obtain metals in free form, but to convert it into an enriched product - matte (sulfide alloy).
   

Smelting copper or nickel ores into matte.

CuS + FeS ₂ + O ₂ + SiO ₂ → Cu ₂ S FeS + FeO SiO ₂ + SO _{2 ( gas )}

^{matte slag}

Melting is carried out in the presence of air. The result is copper matte (an alloy of FeS and Cu ₂ S ) with a higher copper content than the original ore, ferruginous slag and gas. Matte and slag are insoluble in one another and are separated by density. When smelting ore containing 2-5% C u ( concentration and at the same time oxidative).

4. 
   Electrolysis of molten salts (electrolytic smelting). This process produces metal in a solid or liquid state. By electrolysis of molten salts (chlorides, fluorides, oxides, etc.) any metal can be obtained in free form.
   
5. 
   Metallothermic melts;
   
6. 
   Reaction melts based on the interaction of sulfides and oxides when heated.
   

Refining melts. Their purpose is to refining metals from impurities. In this case, differences in the properties of the base metal and impurity metals are used. These swimming trunks have the following varieties.

1. 
   Liquation refining. It is based on the formation and separation by density of two phases, the main one in quantity - liquid or solid - consisting of the metal being refined. The impurity is concentrated in the second solid or liquid phase, which is insoluble in the base metal. For example, copper is poorly soluble in molten lead at 350 ^o C and floats to its surface in the form of a solid solution of lead and copper.
   
2. 
   Distillation refining. The separation of metals in this process is based on the vapor pressure of the metal and its impurities and is carried out either by rectification or by single distillation. For example, magnesium ( t _bp = 1107 ^o C) is distilled from aluminum ( t _bp = 2500 ^o C) from their alloys.
   
3. 
   Oxidative refining. It is based on the difference in oxygen affinity between the base metal and the impurity. For example, iron, as an impurity, is oxidized in molten copper when air is blown into it, and the resulting ferric oxide does not dissolve in liquid copper and floats to its surface:
   

( Cu + Fe ) _l + 0.5 O ₂ → Cu _l + FeO _TV

4. 
   Chlorine refining. This process is based on the different affinities of the metal and impurity for chlorine. For example, zinc can be separated from lead using its greater affinity for chlorine:
   

( Pb + Zn ) _l + Cl ₂ → Pb _l + ZnCl _{2 l}

The resulting zinc chloride does not dissolve in liquid lead and floats to its surface.

5. 
   Sulfiding melts. These processes are based on the different affinities of metals for sulfur. For example, separating copper from lead using sulfur:
   

(Pb + Cu _)l + _S2 →P _bl +C _{u2S t in}

6. 
   Carbonyl refining. It is based on the formation of volatile compounds such as Metal( CO ) _{n by some metals under specially selected conditions} . For example, separating nickel from copper.
   

(Ni + Cu) _l + 4CO→Ni(CO) ₄ +Cu