Compositions and Methods for Purification of Metals from Steel Making Waste Streams
Systems and methods are described in which spent pickle liquor from metal cleaning processes is utilized to regenerate a lixiviant used to recover valuable metals from industrial waste and other sources. The spent pickle liquor is neutralized and solvated metals in the spent pickle liquor are precipitated in this process. When the industrial waste is slag from a metal refining process a partially closed metal production process can be implemented, where spent pickle liquor from cleaning of the refined metal is used to regenerate a lixiviant used to recover a different, valuable metal from a waste slag of the process, with precipitated salts from the lixiviant regeneration being returned as a raw material in the metal refining process. As a result waste streams from these processes are dramatically reduced or eliminated.
1 - 24 . (canceled)
25 . A method for processing a spent pickle liquor, comprising:
obtaining an industrial waste comprising CaO or Ca(OH) 2 ;
contacting the industrial waste with a lixiviant to solvate calcium from the industrial waste as a water soluble calcium salt, thereby generating a calcium-depleted industrial waste and a spent lixiviant; and
contacting the spent lixiviant with the spent pickle liquor, wherein the spent pickle liquor comprises a water soluble salt of a metal, to produce a suspension comprising a regenerated lixiviant and an insoluble salt of the metal.
26 . The method of claim 25 , further comprising the step of separating the insoluble salt of the metal from the regenerated lixiviant.
27 . The method of claim 26 , further comprising the step of recycling the regenerated lixiviant to contact additional industrial waste.
28 . The method of claim 25 , further comprising the step of recovering calcium from the water soluble calcium salt.
28 . The method of claim 25 , wherein the water soluble salt of the metal comprises a counterion, and wherein the counterion is selected to provide the water soluble calcium salt when paired with calcium wherein the counterion is selected from the group consisting of a halide, an organic anion, nitrite, and nitrate.
29 . The method of claim 25 , wherein the metal is selected from the group consisting of iron, copper, aluminum, cobalt, magnesium, barium, strontium, gold, and silver.
30 . The method of claim 25 , further comprising the step of combining the depleted industrial waste and the insoluble salt of the metal to generate a calcium depleted filler.
31 . The method of claim 25 , wherein the metal is iron, and further comprising the step of supplying the insoluble salt of the metal to a steel production process.
32 . An integrated steel making process, comprising:
contacting an iron containing raw material with coke and lime, followed by heating to produce pig iron;
contacting pig iron with oxygen to produce a mixture of steel and a steel slag;
separating the mixture of steel and steel slag to provide a steel and a steel slag;
in a slag extraction process, treating the steel slag with a lixiviant selected to solubilize a metal from the steel slag to produce a mixture comprising a depleted slag, an extracted metal, and spent lixiviant;
treating the steel with a pickling solution to generate a cleaned steel and a spent pickle liquor comprising iron;
contacting the mixture with the spent pickling solution to generate an iron-enriched slag and a solution comprising regenerated lixiviant; and
returning at least a portion of the solution to the slag extraction process.
33 . The method of claim 32 , wherein the iron-enriched slag is returned to the integrated steel making process as a raw material.
34 . The method of claim 33 , further comprising the step of utilizing the iron-enriched slag in a building material.
35 . The method of claim 32 , wherein the extracted metal is calcium.
36 . The method of claim 32 , wherein the lixiviant is used in substoichiometric amounts relative to the content of the metal in the steel slag.
37 . The method of claim 32 , wherein the spent pickle liquor is added as a series of aliquots.
38 . The method of claim 32 , comprising the additional step of recovering the extracted metal from the solution.
39 . An integrated steel making process, comprising:
contacting an iron containing raw material with coke and lime, followed by heating to produce pig iron;
contacting pig iron with oxygen to produce a mixture of steel and a steel slag;
separating the mixture of steel and steel slag to provide a steel and a steel slag;
in a slag extraction process, treating the steel slag with a lixiviant selected to solubilize a metal from the steel slag to produce a mixture comprising a depleted slag, an extracted metal, and spent lixiviant;
treating the steel with a pickling solution to generate a cleaned steel and a spent pickle liquor comprising iron;
separating the mixture to generate a depleted slag and a first solution comprising spent lixiviant;
contacting the first solution with the spent pickling solution to generate second solution comprising a regenerated lixiviant; and
returning at least a portion of the regenerated lixiviant to the slag extraction process.
40 . The method of claim 39 , wherein contacting the first solution with the spent pickle liquor generates an insoluble iron salt, and wherein the insoluble iron salt is returned to the integrated steel making process as a raw material.
41 . The method of claim 39 , further comprising the step of utilizing the depleted slag in a building material.
42 . The method of claim 39 , wherein the extracted metal is calcium.
43 . The method of claim 39 , wherein the lixiviant is used in substoichiometric amounts relative to the content of the metal in the steel slag.
44 . The method of claim 39 , further comprising the step of recovering the extracted metal from the second solution following contact with the spent pickle liquor.