BE454496A - - Google Patents

Description

       

   <EMI ID = 1.1>

  
 <EMI ID = 2.1> The invention consists in introducing the 'vanadate lye

  
of sodium heated to approximately 95 [deg.] in mineral acid (preferably concentrated sulfuric acid) in order to precipitate

  
vanadic acid. It is advisable to operate in such a way that the precipitation which takes place ceases when the reaction shows

  
 <EMI ID = 3.1>

  
be. This operating mode requires, it is true, to carry out the

  
work in two separate acid tanks since the detergent,

  
of sodium vanadate must be heated before it is added to the acid. But this disadvantage is completely offset by

  
this advantage that a prior precipitation of higher quantities of phosphorus' possibly present no longer has any reason to exist and that it becomes possible to work with a

  
higher concentration of vanadium .. We could not predict
- and this; supports the originality of the process - that the phosphorus would remain in solution here and therefore would not disturb the precipitation.

  
'The advantage of the new process results from the following observation: If the sodium vanadate lye contains more

  
of O'gr, 3 of phosphorus per liter, it was not possible by precipitating phosphorus as previously with the aid of calcium chloride to reduce the losses of vanadium during the

  
 <EMI ID = 4.1>

  
were, on the one hand, of the inevitable loss that occurs

  
when precipitating the purified vanadate lye from the

  
 <EMI ID = 5.1>

  
per liter and, on the other hand, more or less losses of vanadium during precipitation and filtration

  
the deposit of calcium phosphate. If, on the other hand, we proceed

  
as the invention recommends, it is observed that without separation
- prior to phosphorus, vanadium losses do not represent <EMI ID = 6.1>

  
dium involved in the precipitation of calcium phosphate disappear. '

  
In the known methods, it was also not possible to work with concentrations greater than 24

  
 <EMI ID = 7.1>

  
the residual lye has a high content of vanadium

  
say to cause great losses. On the contrary, thanks to the process, object of the invention, the concentration of. vanadium

  
in lye can have any suitable value without adversely affecting the physical structure

  
precipitated acids, that is to say without it being muddy, oily or the like. And as, with these high concentrations, one must also count on inevitable losses in

  
 <EMI ID = 8.1>

  
the losses are ultimately much lower than what

  
is the case with the usual processes. since then these losses

  
from 0 gr, 3 to 0 gr, 4 are manifested for a concentration of

  
the starting detergent much lower. So the advantage

  
of the new process also resides in the fact that, for wet processing, only quantities

  
significantly smaller liquid.

  
 <EMI ID = 9.1>


    

Claims (1)

<EMI ID = 10.1> Process .de precipitation of vanadic acid starting from lye of vanadate '. sodium and causing mineral acids to act, characterized in. what .. that! ' So- <EMI ID = 11.1> vanadate lye (preferably concentrated sulfuric acid) so that the precipitation ends when the reaction shows low acidity, i.e. when, at the end of the precipitation and in the case where one uses for example sulfuric acid, the mixture subjected to precipitation contains in- <EMI ID = 12.1>