Compositions comprising oxidized materials for sand casting and methods of preparation and use thereof

Abstract

Compositions useful for green sandcasting are discussed, as well as methods of preparing and using such compositions. Binder compositions may comprise a carbonaceous material, an inorganic binding agent, and a high aspect ratio silicate, wherein at least one of the carbonaceous material or the inorganic material in the binder composition may be oxidized. For example, the inorganic binding agent may be oxidized with a ratio of ferrous iron (Fe 2+ ) to ferric iron (Fe 3+ ) less than 1.2 or less than 1. Green sand prepared from such binder compositions may exhibit a reduction in emissions during sandcasting.

What is claimed is: 
     
         1 . A method of molding an article, the method comprising:
 introducing a heated material into a mold; and   allowing the heated material to cool,   wherein the mold includes a mixture of a binder composition, water, and an aggregate,   wherein the binder composition includes a carbonaceous material and an oxidized inorganic binding agent,   wherein the oxidized inorganic binding agent has a ratio of Fe 2+  to Fe 3+  less than 1.2, and   wherein the mold releases less than 0.10 mg/g BTEX after the introducing of the heated material into the mold.   
     
     
         2 . The method according to  claim 1 , wherein the carbonaceous material is oxidized. 
     
     
         3 . The method according to  claim 1 , wherein the ratio of Fe 2+  to Fe 3+  is less than 1. 
     
     
         4 . The method according to  claim 1 , wherein the binder composition includes from about 70% by weight to about 90% by weight of the oxidized inorganic binding agent, and/or from about 0.1% by weight to about 20.0% by weight of the carbonaceous material. 
     
     
         5 . The method according to  claim 1 , wherein the oxidized inorganic binding agent includes sodium bentonite, calcium bentonite, or a mixture thereof and/or the carbonaceous material comprises oxidized coal, oxidized lignite, oxidized leonardite, oxidized graphite, oxidized anthracite, oxidized cellulose, or a combination thereof. 
     
     
         6 . The method according to  claim 1 , wherein the binder composition further includes a high aspect ratio silicate. 
     
     
         7 . The method according to  claim 6 , wherein the high aspect ratio silicate includes (i) mica or talc, or (ii) muscovite, paragonite, lepidolite, phlogophite, biotite, or a combination thereof. 
     
     
         8 . The method according to  claim 1 , wherein the aggregate includes silica sand, zircon sand, an aluminosilicate, or a mixture thereof. 
     
     
         9 . The method according to  claim 1 , wherein the mold releases less than 0.08 mg/g BTEX after introducing the heated material into the mold. 
     
     
         10 . The method according to  claim 1 , wherein the mold releases less than 0.06 mg/g BTEX after introducing the heated material into the mold. 
     
     
         11 . The method according to  claim 1 , wherein the mold releases less than 0.05 mg/g BTEX after introducing the heated material into the mold. 
     
     
         12 . A mold, comprising:
 a green sand composition, comprising:
 a binder composition, comprising:
 a carbonaceous material; and 
 an oxidized inorganic binding agent; and 
 
 an aggregate, 
   wherein the oxidized inorganic binding agent has a ratio of Fe 2+  to Fe 3+  less than 1.2, and   wherein the mold releases less than 0.10 mg/g BTEX after introduction of a heated material into the mold.   
     
     
         13 . The mold according to  claim 12 , wherein the carbonaceous material is oxidized. 
     
     
         14 . The mold according to  claim 12 , wherein the ratio of Fe 2+  to Fe 3+  is less than 1. 
     
     
         15 . The mold according to  claim 12 , wherein the binder composition includes from about 70% by weight to about 90% by weight of the oxidized inorganic binding agent, and/or from about 0.1% by weight to about 20.0% by weight of the carbonaceous material. 
     
     
         16 . The mold according to  claim 12 , wherein the oxidized inorganic binding agent includes sodium bentonite, calcium bentonite, or a mixture thereof and/or the carbonaceous material comprises oxidized coal, oxidized lignite, oxidized leonardite, oxidized graphite, oxidized anthracite, oxidized cellulose, or a combination thereof. 
     
     
         17 . The mold according to  claim 12 , wherein the binder composition further includes a high aspect ratio silicate. 
     
     
         18 . The mold according to  claim 17 , wherein the high aspect ratio silicate includes (i) mica or talc, or (ii) muscovite, paragonite, lepidolite, phlogophite, biotite, or a combination thereof. 
     
     
         19 . The mold according to  claim 17 , wherein the binder composition comprises from about 0.1% by weight to about 5.0% by weight of the high aspect ratio silicate. 
     
     
         20 . The mold according to  claim 12 , wherein the aggregate includes silica sand, zircon sand, an aluminosilicate, or a mixture thereof. 
     
     
         21 . A binder composition for use in a mold formed from a green sand casting composition including the binder composition and aggregate, the binder composition comprising:
 a carbonaceous material; and   an inorganic binding agent,   wherein either or both of the carbonaceous material and inorganic binding agent is oxidized,   wherein, when oxidized, the oxidized inorganic binding agent has a ratio of Fe 2+  to Fe 3+  less than 1.2, and   wherein the mold releases less than 0.10 mg/g BTEX after introduction of a heated material into the mold.