Method for manufacturing high aspect ratio silver nanowires

Patent metadata

Field	Value
Publication number	US-10376898-B2
Application number	US-201615158257-A
Country	US
Kind code	B2
Filing date	May 18, 2016
Priority date	Jun 12, 2015
Publication date	Aug 13, 2019
Grant date	Aug 13, 2019

Abstract

A method for manufacturing high aspect ratio silver nanowires is provided, wherein the silver solids produced comprise high aspect ratio silver nanowires and are depleted in low aspect ratio silver particles.

First claim

We claim:

1. A method of manufacturing high aspect ratio silver nanowires, comprising:
providing a raw feed, comprising:
a mother liquor; and,
silver solids;
wherein the silver solids in the raw feed include high aspect ratio silver nanowires and low aspect ratio silver particles;

providing a dynamic filtration device, wherein the dynamic filtration device, comprises:
a housing, comprising: a cavity having a first side and a second side;

wherein there is at least one inlet to the first side of the cavity, at least one product outlet from the first side of the cavity and at least one permeate outlet from the second side of the cavity; and,
a porous element disposed within the cavity;
a turbulence inducing element disposed within the cavity; and,
a pressure source;
wherein the porous element is interposed between the first side of the cavity and the second side of the cavity; wherein the porous element has a plurality of passages that traverse from the first side of the cavity to the second side of the cavity; wherein the plurality of passages are large enough to permit transfer of the mother liquor and low aspect ratio silver particles and small enough to block transfer of the high aspect ratio silver nanowires;
wherein the porous element and the turbulence inducing element cooperate to form a filtration gap, FG; and,
wherein at least one of the porous element and the turbulence inducing element is moveable;

transferring the raw feed to the dynamic filtration device through the at least one inlet to the first side of the cavity; wherein the filtration gap, FG, is filled by the mother liquor; wherein the porous element and the turbulence inducing element disposed within the cavity are both in contact with the mother liquor;
pressurizing the first side of the cavity using the pressure source resulting in a first side pressure, FS P , in the first side of the cavity; wherein the first side pressure, FS P , is higher than a second side pressure, SS P , in the second side of the cavity, whereby there is created a pressure drop across the porous element from the first side of the cavity to the second side of the cavity; wherein the pressure source provides a primary motive force for inducing a flow from the first side of the cavity through the porous element to the second side of the cavity providing a permeate;
moving at least one of the porous element and the turbulence inducing element whereby a shear stress is generated in the mother liquor in the filtration gap, FG; wherein the shear stress generated in the mother liquor in the filtration gap, FG, operates to reduce fouling of the porous element;
withdrawing the permeate from the at least one permeate outlet from the second side of the cavity, wherein the permeate comprises a second part of the mother liquor and a second portion of the silver solids; wherein the second portion of the silver solids is rich in low aspect ratio silver particles; and,
withdrawing a product from the at least one product outlet from the first side of the cavity, wherein the product comprises a first part of the mother liquor and a first portion of the silver solids; wherein the first portion of the silver solids is depleted in low aspect ratio silver particles; and,
wherein the shear stress generated in the mother liquor in the filtration gap, FG, and the pressure drop across the porous element from the first side of the cavity to the second side of the cavity are decoupled.

2. The method of claim 1 , further comprising:
providing a transport fluid; and,
transferring a volume of the transport fluid to the dynamic filtration device through the at least one inlet to the first side of the cavity.

3. The method of claim 2 , further comprising:
continuously moving the turbulence inducing element relative to the porous element.

4. The method of claim 3 , wherein the turbulence inducing element provided is an agitator with an impeller; and, wherein the impeller is continuously rotated in a plane disposed in the first side of the cavity.

5. The method of claim 4 , wherein the porous element is a porous membrane;
wherein the porous membrane is flat and has a top surface and a bottom surface; wherein the top surface and the bottom surface are parallel; wherein the porous membrane has a thickness, T, measured from the top surface to the bottom surface along a line (A) normal to the top surface;
and, wherein the top surface is proximate to the turbulence inducing element.

6. The method of claim 5 , wherein each passage in the plurality of passages has a cross sectional area parallel to the top surface; wherein the cross sectional area is uniform across the thickness, T, of the porous membrane.

7. The method of claim 6 , wherein the filtration gap, FG, is defined by the plane and the top surface of the porous element proximate to the impeller.

8. The method of claim 7 , wherein the filtration gap, FG, is 1 to 100 mm.

9. The method of claim 8 , wherein a volumetric flux of permeate through the porous element is 280 to 360 L/m 2 ·hour.

10. The method of claim 9 , wherein the pressure drop across the porous element is 20 to 35 kPa.

Assignees

• Dow Global Technologies Llc

Inventors

• Collins Raymond M
• Mcgough Patrick T
• Bauer William R

Classifications

• B22F1/0025

  Operations & Transport · mapped topic

• B03B5/66 Primary

  of the hindered settling type · CPC title

• B22F9/24

  starting from liquid metal compounds, e.g. solutions · CPC title

• B22F1/0547 Primary

  Nanofibres or nanotubes · CPC title

• B22F1/07

  Metallic powder characterised by particles having a nanoscale microstructure (nanosized particles B22F1/054) · CPC title