Method and Use of an Apparatus for Recovery of Metals or Metal Compounds

Abstract

A method for recovery of metals or metal compounds from metal-bearing solid particles comprising volatile compounds comprises supplying the solid particles ( 50 ) through a flame ( 25 ) of a burner ( 20 ). The volatile compounds are then evaporated by means of heat from the flame ( 25 ) without melting the solid particles, thereby providing a raw material product ( 34 ). The raw material product ( 34 ) is then recovered. By feeding the solid particles directly to the flame, a compact and efficient plant is provided. The melting process can be controlled in a satisfying way, avoiding melting of the metal-bearing solid particles supplied through the burner. The use of a burner is also described.

1 . A method for recovery of metals or metal compounds from metal-bearing solid particles comprising volatile compounds, the method comprising the following steps: 
 a) supplying the solid particles ( 50 ) through a flame ( 25 ) of a burner ( 20 ),    b) bringing the volatile compounds to evaporate by means of heat from the flame ( 25 ) while maintaining the original shape and state of aggregate of the solid particles, thereby providing a raw material product ( 34 ), and    c) recovering the raw material product ( 34 ).    
   
   
       2 . The method according to  claim 1 , wherein the burner ( 20 ) is an oxy-fuel burner.  
   
   
       3 . The method according to  claim 1 , wherein the burner is supplied with an oxidizing gas having an O 2  content of at least 21% O 2 .  
   
   
       4 . The method according to  claim 3 , wherein the burner is supplied with an oxidizing gas having an O 2  content of at least 90% O 2 .  
   
   
       5 . The method according to  claim 1 , wherein the solid particles ( 50 ) comprise zinc oxide.  
   
   
       6 . The method according to  claim 1 , wherein the volatile elements are elements from the group comprising cadmium, lead, different salts, sodium chloride, potassium chloride, oxides, and fluorides.  
   
   
       7 . The method according to  claim 1 , wherein the solid particles ( 50 ) have a diameter of less than approximately 5 millimeters, and more preferably a diameter of less than approximately 1 millimeter.  
   
   
       8 . The method according to  claim 1 , wherein the calcining process of step b) is controlled by means of at least some of the following parameters: temperature and velocity of the flame ( 25 ), energy content or density of the solid particles, the ratio oxidizing gas to added fuel of the burner ( 20 ), the oxygen content of the oxidizing gas, the supply rate of oxygen and added fuel, the oxygen content in exhaust gas, the supply rate of the solid particles and their characteristics, the travel time of the solid particles in the flame, and burner characteristics and configuration, such as tilting.  
   
   
       9 . The method according to  claim 1 , wherein step a) comprises supplying the solid particles ( 50 ) essentially to the central portion of the flame ( 25 ).  
   
   
       10 . The method according to  claim 1 , wherein the solid particles remain in the flame ( 25 ) for less than one second, and more preferably for less than one half second.  
   
   
       11 . Use of an apparatus for recovery of metals and metal compounds from metal-bearing solid particles comprising volatile compounds, the apparatus comprising: 
 a burner ( 20 ) having a flame ( 25 ) during operation thereof,    a feeder ( 40 ) connected to the burner for supplying metal-bearing solid particles comprising volatile compounds through the flame ( 25 ) of the burner ( 20 ),    a device ( 21 , 22 ) for controlling the flame ( 25 ) of the burner ( 20 ) so as to evaporate the volatile compounds by means of heat from the flame while maintaining the original shape and state of aggregate of the solid particles, thereby providing raw material product ( 34 ), and    a device ( 30 ) for recovering the raw material product ( 34 ).