DARCO DARCO DEPARTMENT
· ATLAS POWDER COMPANY
Dorco G e n e r a / Sales Offices—60 EAST 42nd STREET, NEW YORK 1 7 , Ν. Υ . A T L A S POWDER C O M P A N Y , C A N A D A , LTD., B R A N T F O R D , C A N A D A
COUNTER-CURRENT TREATMENT WITH DARCO SAVES CARBON . . .PURIFIES BETTER W h e n a solution is decolorized or otherwise purified b y m e a n s of acti vated carbon, t h e counter-current m e t h o d often proves the m o s t effec t i v e a n d economical w a y t o do t h e j o b . Perfected b y D a r c o technicians, this m e t h o d performs t h e t r e a t m e n t in t w o steps instead of o n e . Initial t r e a t m e n t is m a d e w i t h D a r c o t h a t h a s been used once, a n d final treat m e n t w i t h n e w D a r c o . T h e countercurrent n a m e c o m e s from t h e fact t h a t D a r c o m o v e s through t h e process in the direction opposite t o t h e liquor. T h e principal a d v a n t a g e of countercurrent t r e a t m e n t is s a v i n g s in car b o n . I n comparison w i t h one-step t r e a t m e n t , this m e t h o d uses up to 4 0 per c e n t less D a r c o t o produce t h e same a m o u n t of purifier tion. W h e n retention loss is an i m p o r t a n t eco nomic factor, t h e lower carbon dos a g e results in further s a v i n g s through lower loss of product in t h e filter cake. T h e reason for t h e lower dosage is t h i s : t h e fresh D a r c o first does t h e more difficult job of adsorbing t h e last traces of i m p u r i t y , w h e r e its full a d s o r p t i v e c a p a c i t y is m o s t needed. After doing this, t h e D a r c o still has a m p l e c a p a c i t y for t h e higher impur i t y c o n c e n t r a t i o n i n t h e untreated liquor.
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As particle size becomes smaller, adsorp tive capacity increases because t h e effec tive area is made larger. Filterability, however, drops off as the particles be come small, due to their tendency to clog tightly in the filter.
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The size of particles of activated carbon requires accurate control, in order to arrive at the proper balance between filterability and adsorptive capacity.
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W h i l e a third s t e p of counter-current Strict specifications on particle size of t r e a t m e n t would effect further econ Darco assure you of the best compromise omies in carbon, t w o s t e p s usually between these opposing factors. The car give t h e b e s t overall e c o n o m y of bon is ground so that substantially 100% e q u i p m e n t . F o r further details, write passes a 100-mesh sieve, and about 70% for a c o p y of " H a n d b o o k for Counter- passes a 325-mesh sieve. The correct Current T r e a t m e n t W i t h Activated distribution of particle size provides best overall results. Carbon." VOLUME
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