Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
135 words
A method of removing metallic and acid ions from the liquor of a pickling or metal cleaning tank after it has been used and which has a pH of strong acid comprising the steps of passing a DC current through a pair of spaced current electrodes immersed in said liquor which are separated by an ionic permeable microporous polymer diaphragm dividing the tank of liquor into two parts and which diaphragm permits cations and anions to pass therethrough and which diaphragm is inherently hydrophobic and specially processed to provide a pore structure which blocks the movement of water molecules therethrough, including water of hydration, and forming a removable metallic deposit at the cathode and a substantially purified acid on the anode side of the diaphragm, the current flow through the diaphragm being by ionic movement.
Claim 2
Independent Claim
135 words
A method of removing metallic and acid ions from the liquor of a pickling or metal cleaning tank after it has been used and which has a pH of strong acid comprising the steps of passing a DC current through a pair of spaced current electrodes immersed in said liquor which are separated by an ionic permeable microporous polymer diaphragm dividing the tank of liquor into two parts and which diaphragm permits cations and anions to pass therethrough and which diaphragm is inherently hydrophobic and specially processed to provide a pore structure which blocks the movement of water molecules therethrough, including water of hydration, and forming a removable metallic deposit at the cathode and a substantially purified acid on the anode side of the diaphragm, the current flow through the diaphragm being by ionic movement.
Claim 3
Dependent Claim
24 words
The method of claim 1 wherein the electrods are plates which are connected to a DC voltage source of about three to four volts.
Claim 4
Dependent Claim
30 words
The method of claim 1 wherein the anode side of the tank is initially filled with water and the liquor is initially introduced into the cathode side of the tank.
Claim 5
Dependent Claim
38 words
The method of claim 1 wherein the metal ions of the pickle liquor in the vicinity of the cathode are removed as a solid and any remaining metal ions in solution are removed by a subsequent removal step.
Claim 6
Dependent Claim
30 words
The method of claim 1 wherein the metallic deposit formed at the cathode is permitted to accumulate until its presence at the cathode drops the current flow through the cathode.
Claim 7
Dependent Claim
22 words
The method of claim 1 wherein the current flow ranges upwardly from zero to a limit determined by heating of the cathode.
Claim 8
Dependent Claim
15 words
The method of claim 1 wherein the metallic deposit is mechanically removed from the cathode.
Claim 9
Dependent Claim
26 words
The method of claim 1 wherein the acid is sulfuric acid and the sulfate ions pass through the membrane to the anode side of the tank.
Claim 10
Dependent Claim
15 words
The method of claim 1 wherein said diaphragm is a hydrophobic, open-celled, microporous polypropylene film.
Claim 11
Dependent Claim
20 words
The method of claim 1 wherein said diaphragm has elongate pores having a size of about 40 by 400 angstroms.
Claim 12
Dependent Claim
27 words
The method of claim 1 wherein said diaphragm is formed of pores of about 40 angstroms which size enables acid and metal ions to pass bidirectionally therethrough.