Inhibiting Toxicity of Acid Systems Used for Treating Metals

Abstract

In some examples of inhibiting toxicity of acid systems used for treating metals, a metal is pickled with a pickling composition that includes a first quantity of an acid and a second quantity of a corrosion inhibiting iodide salt. A mixture of the first quantity and the second quantity modify metallic properties of the pickled metal. The corrosion inhibiting iodide salt is added directly to the pickling composition independent of any other corrosion inhibitor or corrosion inhibiting polymer.

What is claimed is: 
     
         1 . A method of pickling a metal, the method comprising:
 pickling a metal with a pickling composition comprising a first quantity of an acid and a second quantity of a corrosion inhibiting iodide salt, wherein a mixture of the first quantity of the pickling composition and the second quantity of the corrosion inhibiting iodide salt modify metallic properties of the pickled metal.   
     
     
         2 . The method of  claim 1 , wherein the acid comprises sulfuric acid. 
     
     
         3 . The method of  claim 1 , wherein the corrosion inhibiting iodide salt comprises potassium iodide. 
     
     
         4 . The method of  claim 1 , wherein the second quantity of the corrosion inhibiting iodide salt is added directly to the first quantity of the pickling composition independent of any other corrosion inhibitor. 
     
     
         5 . The method of  claim 1 , wherein the second quantity of the corrosion inhibiting iodide salt is mixed with the first quantity of the pickling composition at a temperature greater than room temperature. 
     
     
         6 . The method of  claim 5 , wherein the temperature is at least about 60° C. 
     
     
         7 . The method of  claim 6 , wherein the temperature ranges between about 60° C. and 80° C. 
     
     
         8 . The method of  claim 1 , wherein the acid in the pickling composition has a molarity of either 0.5 M or 1.0 M. 
     
     
         9 . The method of  claim 1 , wherein the metal comprises carbon steel. 
     
     
         10 . The method of  claim 1 , wherein pickling the metal with the pickling composition including the corrosion inhibiting iodide salt comprises soaking the metal in the pickling composition for a period of time. 
     
     
         11 . The method of  claim 10 , wherein the period of time comprises at up to about six hours. 
     
     
         12 . The method of  claim 1 , wherein a ratio of the second quantity to the first quantity ranges between greater than 0 g of iodide salt per 100 mL of acid to about 0.5 g of iodide salt per 100 mL of acid. 
     
     
         13 . The method of  claim 1 , wherein the first quantity and the second quantity are selected such that the pickling composition including the corrosion inhibiting iodide salt has a corrosion rate of less than about 0.05 Ib/sq. ft. 
     
     
         14 . A method of pickling a metal, the method comprising:
 obtaining a first quantity of a pickling composition comprising an acid, the pickling composition to modify metallic properties of the pickled metal;   obtaining a second quantity of a corrosion inhibiting iodide salt;   to inhibit a corrosiveness of the pickling composition, mixing the second quantity of the corrosion inhibiting iodide salt and no other corrosion inhibitor with the first quantity of the pickling composition; and   pickling the metal with the pickling composition including the corrosion inhibiting iodide salt.   
     
     
         15 . The method of  claim 14 , wherein a ratio of the second quantity to the first quantity ranges between greater than 0 g of iodide salt per 100 mL of acid to about 0.5 g of iodide salt per 100 mL of acid. 
     
     
         16 . The method of  claim 14 , wherein the first quantity and the second quantity are selected such that the pickling composition including the corrosion inhibiting iodide salt has a corrosion rate of less than about 0.05 Ib/sq. ft. 
     
     
         17 . The method of  claim 14 , wherein the acid in the pickling composition has a molarity of either 0.5 M or 1.0 M. 
     
     
         18 . A method of pickling a metal, the method comprising:
 mixing a first quantity of a pickling composition comprising an acid, the pickling composition to modify metallic properties of the pickled metal, with a second quantity of a corrosion inhibiting iodide salt that is independent of any corrosion inhibiting polymer; and   pickling the metal with the pickling composition including the corrosion inhibiting iodide salt.   
     
     
         19 . The method of  claim 19 , wherein the acid comprises sulfuric acid. 
     
     
         20 . The method of  claim 19 , wherein the corrosion inhibiting iodide salt comprises potassium iodide.