Method and apparatuses for screening

Abstract

Embodiments of the present disclosure include a screen basket apparatus includes a substantially vertical cylindrical frame and a synthetic screening surface secured to the frame. The synthetic screening surface may be configured to separate carbon or resin from a slurry of a carbon-in-leach, carbon-in-pulp, resin-in-leach, or resin-in-pulp material as fluid flows from outside to inside the screen basket apparatus such that carbon or resin is retained on an external surface of the synthetic screening surface. The cylindrical frame may be a grid frame and the synthetic screening surface may include a plurality of replaceable screen assemblies attached to the grid frame. The grid frame may include a plurality of openings and each of the plurality of openings is configured to receive a respective one of the plurality of replaceable screen assemblies. The synthetic screening surface may include injected molded thermoplastics, thermoset polyurethanes, and/or other polymeric materials.

What is claimed is: 
     
         1 . A screen basket apparatus, comprising:
 a substantially vertical cylindrical frame; and   a synthetic screening surface secured to the frame,   wherein the synthetic screening surface is configured to separate carbon or resin from a slurry of a carbon-in-leach (CIL), carbon-in-pulp (CIP), resin-in-leach (RIL), or resin-in-pulp (RIP) material as fluid flows from outside the screen basket apparatus to inside the screen basket apparatus due at least in part to a static pressure differential between fluid outside relative to fluid inside the screen basket apparatus, such that carbon or resin is retained on an external surface of the synthetic screening surface.   
     
     
         2 . The screen basket apparatus of  claim 1 , further comprising a wiper assembly that urges the fluid from the outside of the screen basket apparatus to the inside of the screen basket apparatus. 
     
     
         3 . The screen basket apparatus of  claim 1 , wherein the synthetic screening surface includes a plurality of corrugations. 
     
     
         4 . The screen basket apparatus of  claim 3 , wherein the corrugations are oriented horizontally. 
     
     
         5 . The screen basket apparatus of  claim 4 , further comprising a wiper assembly that urges the fluid from the outside of the screen basket apparatus to the inside of the screen basket apparatus, wherein the wiper assembly includes a plurality of horizontally oriented corrugations that are complementary to the corrugations in the synthetic screening surface. 
     
     
         6 . The screen basket assembly of  claim 1 , further comprising an impeller assembly inside of the screen basket apparatus that agitates screened fluid and urges the screened fluid toward an outlet. 
     
     
         7 . The screen basket apparatus of  claim 1 , wherein the cylindrical frame is a grid frame and the synthetic screening surface includes a plurality of replaceable screen assemblies attached to the grid frame. 
     
     
         8 . The screen basket apparatus of  claim 7 , wherein the grid frame has a plurality of openings and each of the plurality of openings is configured to receive a respective one of the plurality of replaceable screen assemblies. 
     
     
         9 . The screen basket apparatus of  claim 1 , wherein the synthetic screening surface is attached to the frame with an attachment mechanism. 
     
     
         10 . The screen basket apparatus of  claim 9 , wherein the attachment mechanism includes one or more screw or bolt holes configured to receive respective one or more screws or bolts to thereby secure the synthetic screening surface to the frame. 
     
     
         11 . The screen basket apparatus of  claim 8 , wherein the screen assemblies are flexible and are each shaped to pressure fit into a respective one of the openings in the grid frame. 
     
     
         12 . The screen basket apparatus of  claim 11 , wherein the grid frame includes a plurality of transversal and longitudinal members, and
 wherein each screen assembly includes flexible attachment members that are configured to engage with and to pressure fit with adjacent transversal and/or longitudinal members to thereby secure the screen assembly to the grid frame.   
     
     
         13 . The screen basket apparatus of  claim 1 , wherein the synthetic surface includes openings having sizes in a range from approximately 35 microns to approximately 4000 microns. 
     
     
         14 . The screen basket apparatus of  claim 1 , wherein the synthetic screening surface incudes a polyurethane screen forming a screening surface facing outside the screen basket. 
     
     
         15 . The screen basket apparatus of  claim 14 , wherein the polyurethane screen includes screen openings having a length of about 500 microns to about 1200 microns. 
     
     
         16 . The screen basket apparatus of  claim 1 , wherein the synthetic screening surface includes a plurality of screen elements, each screen element including a single injection molded piece integrally formed by injection molding of a thermoplastic material, and 
     
     
         17 . The screen basket apparatus of  claim 16 , wherein the screen elements include a substantially planar screening surface having multiple elongated screening openings. 
     
     
         18 . The screen basket apparatus of  claim 16 , wherein the screen elements include a corrugated screening surface having multiple elongated screen openings. 
     
     
         19 . The screen basket apparatus of  claim 16 , wherein each of the multiple elongated screening openings has a substantially uniform length and a substantially uniform width, the substantially uniform length is between about 300 μm and about 4000 μm, and the substantially uniform width is between about 35 μm and about 4000 μm. 
     
     
         20 . The screen basket apparatus of  claim 7 , wherein the screening assemblies have a corrugated shape and are aligned in a transversal direction relative to a longitudinal axis of the cylindrical fame. 
     
     
         21 . The screen basket apparatus of  claim 7 , wherein the screening assemblies have a corrugated shape and are aligned in a longitudinal direction relative to a longitudinal axis of the cylindrical fame. 
     
     
         22 . A screen basket apparatus, comprising:
 a substantially vertical cylindrical grid frame having a plurality of openings, the grid frame including a plurality of first members and a plurality of second members that define the plurality of openings,   wherein each of the plurality of openings is configured to receive a respective one of a plurality of screen assemblies, and   wherein the screen basket apparatus is configured for use in separating carbon or resin from a slurry of a CIL, CIP, RIL or RIP material as fluid flows from outside the screen basket apparatus to inside the screen basket apparatus.   
     
     
         23 . The screen basket apparatus of  claim 22 , wherein at least one of the plurality of openings includes an attachment mechanism configured to secure at least one of the independent replaceable screen assemblies to the at least one of the plurality of openings. 
     
     
         24 . A method of screening, comprising:
 introducing a screen basket apparatus into a slurry of CIL, CIP, RIL, or RIP material, the screen basket apparatus having a substantially vertical cylindrical frame and a synthetic screening surface secured to the frame;   generating a static pressure differential between fluid outside the screen basket apparatus relative to fluid inside the screen basket apparatus to thereby cause fluid to flow from outside the screen basket apparatus to inside the screen basket apparatus; and   screening the material such that carbon or resin is retained on an external surface of the synthetic screening surface.   
     
     
         25 . The method of  claim 24 , wherein the cylindrical frame is a grid frame and the synthetic screening surface includes a plurality of replaceable screen assemblies attached to the grid frame. 
     
     
         26 . The method of  claim 24 , wherein the synthetic screening surface comprises a substantially flat surface. 
     
     
         27 . The method of  claim 24 , wherein the synthetic screening surface comprises a corrugated screen surface. 
     
     
         28 . The method of  claim 24 , further comprising the step of applying a wiper assembly to the fluid that urges the fluid from the outside of the screen basket apparatus to the inside of the screen basket apparatus. 
     
     
         29 . The method of  claim 28 , wherein the wiper assembly includes a flat wiping surface. 
     
     
         30 . The method of  claim 28 , wherein the wiper assembly includes a corrugated wiping surface. 
     
     
         31 . The method of  claim 27 , wherein the corrugated screen surface comprises corrugations that are oriented horizontally. 
     
     
         32 . The method of  claim 31 , further comprising the step of applying a wiper assembly to the fluid that urges the fluid from the outside of the screen basket apparatus to the inside of the screen basket apparatus, wherein the wiper assembly includes a plurality of horizontally oriented corrugations that are complementary to the corrugations in the synthetic screening surface. 
     
     
         33 . The method of  claim 24 , further comprising the step of operating an impeller assembly inside of the screen basket apparatus that agitates screened fluid and urges the screened fluid toward an outlet. 
     
     
         34 . The method of  claim 24 , wherein the screen basket apparatus further comprises a subgrid assembly and a plurality of screen elements supported by the subgrid assembly. 
     
     
         35 . The method of  claim 34 , wherein the synthetic screening surface has screen openings ranging in size from about 35 to about 250 microns. 
     
     
         36 . The method of  claim 24 , wherein the screen basket apparatus comprises a plurality of single piece injection molded screen elements. 
     
     
         37 . The method of  claim 36 , wherein the screen basket apparatus is devoid of a subgrid assembly. 
     
     
         38 . The method of  claim 36 , wherein the synthetic screening surface has screen openings ranging in size from about 250 to about 4000 microns. 
     
     
         39 . The method of  claim 28 , wherein the synthetic screening surface includes a plurality of elongated screen openings that are oriented parallel to a direction of travel of the wiper assembly.