Recycle process for a metal bearing sludge concentrate

Abstract

A recycling treatment of heavy metal sludge uses a cracking process which releases macromolecular agglutinant and a metal hydrate mixture. Next the mixture is acidified in a primary homogenization process and then a primary separation process separates the macromolecular agglutinant and acid solution with metal ions. A second homogenization process adjusts the pH value of the acid solution with metal ions to be alkaline and then a second separation process separates copper oxide and the remaining salt solution with oxidant. Lastly, salt compounds and oxidant solution is separated through the use of a crystal separation process.

1 . A recycling treatment of heavy metal sludge which includes: 
 The cracking process, in which the sludge is mixed with a sulphuric acid solution and peroxide proportional to the sludge in weight and treated under high temperature and normal pressure,    After a certain period of reaction, macromolecular agglutinant and a metal hydrate mixture are released;    The primary homogenization process, which adjusts the pH value of the mixture after the cracking process to be acidic;    The primary separation process, which mixes the acid mixture from the primary homogenization process to separate macromolecular agglutinant and acid solution with metal ions;    The second homogenization process, which adjusts the pH value of the acid solution with metal ions to be alkaline;    The second separation process, which separates copper oxide and the remaining salt solution with oxidant after second homogenization; and    The crystal separation process, which treats the remaining acid exhausted liquid after second separation to filter out salt compounds and oxidant solution.    
     
     
         2 . For the cracking process mentioned in  claim 1  of the heavy metal sludge recycling treatment, the weight ratio of peroxide and sludge is 0.5-2 to 40-50.  
     
     
         3 . The peroxide used in the cracking process mentioned in  claim 1  of the heavy metal sludge recycling treatment can be hydrogen peroxide, dibutyl peroxide, dicumyl peroxide, (tertbutyl peroxide) hexene, (tertbutyl peroxide) hexane.  
     
     
         4 . The primary homogenization process mentioned in  claim 1  uses one or more acid solution including sulphuric acid, hydrochloric acid, nitric acid and micro etching exhausted liquid to change the pH value.  
     
     
         5 . The secondary homogenization process mentioned in  claim 1  uses one or more alkaline solution including sodium hydroxide, lime, ammonia and etching exhausted liquid to change the pH value.  
     
     
         6 . The temperature used in the cracking process mentioned in  claim 1  is between 200° C. and 250° C.  
     
     
         7 . The time needed for the process of cracking mentioned in  claim 1  is three to six hours.  
     
     
         8 . The best pH value for primary homogenization process mentioned in  claim 1  should be 2 to 7.  
     
     
         9 . The best pH value for secondary homogenization process mentioned in  claim 1  should be 7 to 10.  
     
     
         10 . The products of the crystal separation process mentioned in  claim 1  include: sodium sulphate, ammiaonia sulfate, sodium chloride, sodium chloride, sodium nitrate, ammonium nitrate, calcium sulphate and calcium chloride.  
     
     
         11 . The digesting process mentioned in  claim 1  is used to mix either the existing micro etching exhausted liquid from a printed circuit board factory or any normal acid with the sludge mixture in the process of cracking.  
     
     
         12 . The digesting process mentioned in  claim 1  can further use the hydrate treated in primary separation or the hydrate can be used in the primary homogenization and/or secondary homogenization to be mixed with the sludge mixture.  
     
     
         13 . The copper oxide produced in the process as described in  claim 1  contains a copper content of 30-50% of its weight.  
     
     
         14 . For the macromolecular agglutinant mentioned in  claim 1  in the patent application, the content of macromolecule is 20-40% in weight.  
     
     
         15 . For the oxidant solution mentioned in  claim 1  in the patent application, the oxidizing ability can reach the standard of sewage discharge of COD 200 to 500 ppm after adding 3.0-9.0 permillage in weight.