Powdered metals extracted from acid mine drainage and their use in the manufacture of pressed metal articles

Abstract

Acid mine drainage is treated to form a wet meal-containing precipitate. Such wet metal containing precipitate is dried and processed to form a powder which contains one or more metals. The powder (alone or in combination with other metal powders or other additives) is then compressed (e.g., pressed in a die, rolled, extruded) and sintered to form a desired sintered metal article. In some embodiments, the sintered metal article may be subjected to one or more secondary processes (e.g., oil impregnation, resin impregnation, metal infiltration, copper infiltration, heat treating, steam oxidizing, plating and secondary machining) to alter the strength, configuration or other property of the pressed metal article.

1 . A powdered metal preparation useable in the formation of pressed metal articles, at least a portion of said powdered metal preparation comprising an iron-containing powder obtained from iron-containing acid mine drainage. 
   
   
       2 . A preparation according to  claim 1  further comprising an additional metal powder obtained from a source other than acid mine drainage. 
   
   
       3 . A preparation according to  claim 1  wherein the iron-containing powder obtained from iron-containing acid mine drainage comprises a dry iron-bearing precipitate that has precipitated and separated from iron-containing acid mine drainage. 
   
   
       4 . A preparation according to  claim 3  wherein the dry iron-bearing precipitate comprises iron and calcium as the two most prevalent metals by weight percentage. 
   
   
       5 . A preparation according to  claim 3  wherein the dry iron-bearing precipitate is formed by a method comprising the steps of:
 obtaining a wet metal-containing precipitate from metal-containing acid mine drainage; and   heating the wet metal-containing precipitate in an oxide reducing atmosphere at a temperature of approximately 400 degrees F. to approximately 2070 degrees F., thereby forming the dry iron-bearing precipitate.   
   
   
       6 . A preparation according to  claim 5  wherein the method further comprises the step of:
 removing undesirable material.   
   
   
       7 . A preparation according to  claim 6  wherein the undesirable material comprises a material that was added to the acid mine drainage to facilitate formation of the wet metal-containing precipitate. 
   
   
       8 . A preparation according to  claim 7  wherein the undesirable material comprises a polymer. 
   
   
       9 . A preparation according to  claim 7  wherein the undesirable material comprises calcium. 
   
   
       10 . A preparation according to  claim 2  wherein the additional metal powder comprises iron powder. 
   
   
       11 . A preparation according to  claim 2  wherein the additional metal powder comprises bronze powder. 
   
   
       12 . A preparation according to  claim 2  wherein the additional metal powder comprises bronze powder. 
   
   
       13 . A preparation according to  claim 2  wherein the additional metal powder comprises copper powder. 
   
   
       14 . A preparation according to  claim 1  further comprising a lubricant. 
   
   
       15 . A preparation according to  claim 14  wherein the lubricant acts as a die release agent. 
   
   
       16 . A preparation according to  claim 14  wherein the lubricant comprises paraffin or a paraffin-containing material. 
   
   
       17 . A preparation according to any of  claims 1  through  16  wherein the preparation has been compressed and sintered to form a sintered metal article. 
   
   
       18 . A preparation according to  claim 17  wherein the sintered metal article comprises an article selected from the group consisting of: bearings, gears, rings, housings, bushings, cams, rollers, levers, sprockets, housings, pillow blocks, clamps and structural parts.