Contact and adsorbent granules

Abstract

The present invention relates to a filtering unit at least partially filled with particles agglomerated from fine-particle iron oxide and/or iron oxyhydroxide by producing an aqueous suspension of fine-particle iron oxides and/or iron oxyhydroxides having a BET surface area of 50 to 500 m 2 /g, and removing the water and dissolved constituents by a set of washing drying and filtering steps and processes of using the particles.

What is claimed is:  
     
         1 . A unit suitable for the through-flow of a fluid medium, at least partially filled with particles agglomerated from fine-particle iron oxide and/or iron oxyhydroxide, wherein the fine-particle iron oxide and/or iron oxyhydroxide displays a particle size of up to 500 nm and a BET surface area of 50 to 500 m 2 /g.  
     
     
         2 . The unit of  claim 1  wherein the medium comprises a gas.  
     
     
         3 . The unit of  claim 1  wherein the medium comprises a liquid.  
     
     
         4 . The unit of  claim 3 , wherein the liquid comprises water.  
     
     
         5 . A water treatment plant comprising the unit of  claim 4 .  
     
     
         6 . A waterwork comprising the water treatment plant of  claim 5 .  
     
     
         7 . The unit of  claim 1  wherein the fine-particle iron oxide and/or iron oxyhydroxide displays a BET surface area of 80 to 200 m 2 /g.  
     
     
         8 . The unit of  claim 1  wherein the agglomerates further comprise iron oxide pigments with particle sizes above 500 nm and BET surface areas below 50 m 2 /g, whereby the maximum content of these is such that the resistance of the charge to the forces exerted upon it by the flowing medium is sufficiently great that the stress exerted on the charge by the flowing medium does not lead to an undesirable abrasion of the charge material.  
     
     
         9 . A process for the production of particles from fine-particle iron oxide and/or iron oxyhydroxide comprising the steps of producing an aqueous suspension of fine-particle iron oxides and/or iron oxyhydroxides having a BET surface area of 50 to 500 m 2 /g, and removing the water and dissolved constituents by 
 either 
 I) a) first removing only the water from the suspension, b) introducing the residue thus obtained in water, c) filtering the material obtained, d) washing the residue, and e) either e1) completely dehydrating the filter cake obtained as residue and comminuting the material thus obtained to the desired shape and/or size or e2) partially dehydrating the filtercake to obtain a paste, shaping the paste and subsequently additionally drying the paste until a pellet is obtained,  
   or 
 II) a) filtering the suspension, b) washing the residue, c) either c1) completely dehydrating the filter cake obtained as residue in the form of a solid to semisolid paste and then comminuting the material thus obtained to the desired shape and/or size or c2) partially dehydrating the filtercake to obtain a paste, shaping the paste, and subsequently additionally drying the paste until a pellet is obtained.  
   
     
     
         10 . The process of  claim 9  further comprising a step of subjecting the pellet to a further comminution by grinding or rough grinding.  
     
     
         11 . The process of  claim 9  wherein the BET surface area is 80 to 200 m 2 /g.  
     
     
         12 . The process of  claim 9  wherein I) a) the water is removed by evaporation.  
     
     
         13 . The process of  claim 9  comprising I d) washing the residue until it is free from salts.  
     
     
         14 . The process of  claim 9  comprising II b) washing the residue until it is low in salts.  
     
     
         15 . A process comprising treating fluid medium by contacting the gas or liquid in a unit according to  claim 1  with particles obtained by a process for the production of particles from fine-particle iron oxide and/or iron oxyhydroxide comprising the steps of producing an aqueous suspension of fine-particle iron oxides and/or iron oxyhydroxides having a BET surface area of 50 to 500 m 2 /g, and removing the water and dissolved constituents by 
 either 
 I) a) first removing only the water from the suspension, b) introducing the residue thus obtained in water, c) filtering the material obtained, d) washing the residue, and e) either e1) completely dehydrating the filter cake obtained as residue and comminuting the material thus obtained to the desired shape and/or size or e2) partially dehydrating the filtercake to obtain a paste, shaping the paste and subsequently additionally drying the paste until a pellet is obtained,  
 
 or 
 II) a) filtering the suspension, b) washing the residue, c) either c1) completely dehydrating the filter cake obtained as residue in the form of a solid to semisolid paste and then comminuting the material thus obtained to the desired shape and/or size or c2) partially dehydrating the filtercake to obtain a paste, shaping the paste, and subsequently additionally drying the paste until a pellet is obtained.  
 
 
     
     
         16 . The process of  claim 15  wherein the fluid medium comprises water.  
     
     
         17 . The process of  claim 15  comprising removing a heavy metal, phosphorus, antimony, beryllium, selenium, tellurium or cyano compound from water.  
     
     
         18 . The process of  claim 15  comprising removing arsenic compounds from water.