Kipawa - Metallurgy

Matamec’s current optimized process (July 21, 2011) is shown to potentially reduce the cost of the sulphuric acid and limestone needed by over 90% and completely eliminates the cost of heating in the leaching step as compared to its earlier treatment process (Oct 18, 2010).  The substantial reduction in cost demonstrates Matamec’s success in developing a simple and low-cost process for recovering valuable rare earths from its coarse-grained Eudialyte ore. The table below compares the standard treatment process for silicate REE bearing minerals to Matamec’s current optimized process:
 

Standard Treatment Process for silicate REE bearing minerals = Matamec’s Earlier Metallurgical Treatment Process (October 18, 2010)	Matamec’s Current Metallurgical Treatment Process (July 21, 2011)
No Concentration	Magnetic Concentration 35% of original ore mass
Acid Bake	Acid Bake
Acid: 600 kg acid /t ore	No Bake Required
Temperature: 150 ºC
Time 4 hours
Leaching	Leaching
Acid: no	Acid: 150 kg acid /t concentrate
Temperature: 90 ºC	Temperature: 25 ºC
Time 1.5 hour	Time 2 hours
Neutralization	Neutralization
Limestone	Limestone

 
Matamec began its search for a feasible metallurgical process in March 2010 at SGS Minerals Services, supervised by Les Heymann, P.Eng.  The standard baking and leaching method, which is a commonly employed technique for solubilizing REE bearing silicate minerals, was used at that time (October 18, 2010).  Matamec’s earlier treatment process included an acid baking step on the whole-ore, using 600 kg/t of acid at 150 ºCfor 4 hours.  Realizing the high costs associated with the high acid dosage and temperature, Matamec started to optimize the treatment process with two goals in mind: 1) to use physical techniques to produce a pre-concentrate, and 2) to reduce the total acid consumption.  In the past 10 months, Matamec has succeeded in reaching both of these goals.  It has led to a drastic simplification of the treatment process, which in turn improves the economics of the Kipawa project both in operating costs and capital expense.
 
One of the key achievements of Matamec’s metallurgical process is the success of its physical concentration step.  The ability to concentrate rare earths into 35% of the original ore mass, while rejecting the remaining 65% as waste, results in significant savings in reagent dosages. In combination with the significant reduction in acid dosage from 600 kg/t of ore down to 150 kg/t of concentrate, the sulphuric acid cost is potentially reduced by over 90%.  The cost of limestone, which is used for neutralization, is also similarly reduced by over 90%. 
 
Matamec’s proprietary leaching process replaces the energy-intensive acid baking step with a direct room-temperature leach, and the heating cost is completely eliminated.