Pin chip recovery

Abstract

A method is described for separating pin chips from a wood furnish of wood chips, pin chips and fines mixture. In the method, the wood chips are separated from the pin chip and fines mixture and treated with a surfactant to lower the interfacial surface tension between the pin chip and the fibers. The resulting treated pin chip and fines mixture is then mechanically separated into the individual pin chip and fines fraction.

1 . A method for recovering pin chips from a wood furnish comprising the steps of:
 providing a mixture comprising pin chips and fines;   treating said pin chip and fines mixture with a surfactant to separate said fines from said pin chips;   separating said pin chips from said fines mixture;   wherein said separated pin chips are subsequently used for fiber recovery.   
     
     
         2 . The method of  claim 1  wherein said surfactant is a non ionic surfactant. 
     
     
         3 . The method of  claim 1  wherein said surfactant is anionic surfactant. 
     
     
         4 . The method of  claim 1  wherein said surfactant is a cationic surfactant. 
     
     
         5 . The method of  claim 1  wherein said surfactant is a ampholytic/zwitterionic surfactant. 
     
     
         6 . The method of  claim 1  wherein the surfactant is applied from a solution of from 100 to 5000 ppm. 
     
     
         7 . The method of  claim 1  wherein the surfactant is applied from a solution of from 500 to 1000 ppm. 
     
     
         8 . The method of  claim 1  wherein the surfactant is applied from a solution of from 500 to 750 ppm. 
     
     
         9 . A method for recovering pin chips from a wood furnish comprising the steps of:
 providing a mixture comprising pin chips and fines;   drying said pin chip and fines mixture to separate said fines from said pin chips;   separating said pin chips from said fines mixture;   wherein said separated pin chips are subsequently used for fiber recovery.   
     
     
         10 . The method of  claim 9  wherein the surface of the pin chips is air dried. 
     
     
         11 . The method of  claim 9  wherein said mixture of pin chips and fines are dried to a solids level of at least 85 percent. 
     
     
         12 . The method of  claim 9  wherein said mixture of pin chips and fines are dried to a solids level of at least 89 percent.