Processes for treating tailings streams

Abstract

Provided are processes for treating a tailings stream which comprises water and solids, the process comprising: (i) adding one or more anionic polymer flocculants and one or more nonionic polymer flocculants to the tailings stream; (ii) allowing at least a portion of the solids to flocculate; and (iii) separating at least a portion of the flocculated solids from the tailings stream.

We claim: 
     
         1 . A process for treating a tailings stream which comprises water and solids, the process comprising:
 (i) adding one or more anionic polymer flocculants and one or more nonionic polymer flocculants to the tailings stream;   (ii) allowing at least a portion of the solids to flocculate; and   (iii) separating at least a portion of the flocculated solids from the tailings stream.   
     
     
         2 . The process of  claim 1 , wherein the one or more anionic polymer flocculants is added before the one or more polymer nonionic flocculant. 
     
     
         3 . The process of  claim 1 , wherein the one or more nonionic polymer flocculants is added before the one or more polymer anionic flocculant. 
     
     
         4 . The process of  claim 1 , wherein the one or more anionic polymer flocculants and the one or more nonionic polymer flocculants are premixed before being added to a tailings stream. 
     
     
         5 . The process of  claim 1 , wherein the addition of the one or more anionic flocculant and the one or more nonionic flocculant accelerates the consolidation and/or sedimentation of the flocculated solids in the tailings streams. 
     
     
         6 . The process of  claim 1 , wherein the one or more anionic polymer flocculants are a dry blend, in an emulsion or in an aqueous solution. 
     
     
         7 . The process of  claim 1 , wherein the one or more nonionic polymer flocculants are a dry blend, in an emulsion or in an aqueous solution. 
     
     
         8 . The process of  claim 4 , wherein the premixed flocculants are in a dry blend, in an emulsion or in an aqueous solution. 
     
     
         9 . The process of  claim 1 , where in the ratio of the dosage one or more anionic polymer flocculants to the one or more nonionic polymer flocculants is from about 1:100 to about 100:1 by weight. 
     
     
         10 . The process of  claim 1 , where in the ratio of the dosage of one or more anionic polymer flocculants to the one or more nonionic polymer flocculants is about 1:1 by weight. 
     
     
         11 . The process of  claim 1 , where in the ratio of the dosage of one or more anionic polymer flocculants to the one or more nonionic polymer flocculants is from about 1:1 to about 10:3 by weight. 
     
     
         12 . The process of  claim 1 , wherein the total dosage of the one or more anionic polymer flocculants and the one or more nonionic polymer flocculants is about 500 to about 10000 g/t dry tailings. 
     
     
         13 . The process of  claim 1 , wherein the separation of the solids from the tailings stream is by centrifuge, hydrocyclone, decantation, filtration, thickening or another mechanical separation. 
     
     
         14 . The process of  claim 1 , wherein the process further comprises a desanding step.