Abstract A process for regeneration of spent and partially spent metal treating solutions, such as used for treating aluminum. The process includes collecting a portion of the metal-treating solution with the collected solution containing metal salts dissolved from the metal being treated in a treating space, recirculating a portion of the collected solution, and flowing the remainder into a clarifying stage where a precipitating agent is introduced and mixed therewith and solids formed at said stage settled out providing a clarified supernatant solution which is returned to the treating space. The metal salts removed are in the class of carbonates, sulfates, chromates and aluminates and the precipitating agent is an alkaline earth hydroxide, such as calcium hydroxide, barium hydroxide and strontium hydroxide.
The process for regeneration of metal-treating solutions as set forth in claim 1 including: a. a first step wherein the precipitating agent is calcium hydroxide to precipitate carbonates and aluminates and gross amounts of sulfates; and b. a second step wherein the precipitating agent is barium hydroxide to precipitate additional sulfAtes and chromates.
Claim 2
Dependent Claim
36 words
The process for regeneration of metal treating solutions as set forth in claim 1 including: a. forming said precipitating agent by mixing a material of the class of calcium oxide and barium oxide with deionized water.
Claim 3
Dependent Claim
57 words
The process for regeneration of metal treating solutions as set forth in claim 3 including: a. collecting the precipitated solids formed in the mixture of collected solution portion and precipitating agent; b. separating solids from the mixed solution by filtering same to form a substantially solid free filtrate; and c. flowing the filtrate to the treating receptacle.
Claim 4
Dependent Claim
43 words
The process for regeneration of metal-treating solutions as set forth in claim 4 including: a. recirculating the collected solution portion by returning same to the treating receptacle for substantially reducing stratification in said treating solution and improving the treating of the metal therein.
Claim 5
Dependent Claim
34 words
The process for regeneration of metal treating solutions as set forth in claim 5 including: a. maintaining a concentration of the metal salts within the metal treating solution substantially at a constant selected level.
Claim 6
Dependent Claim
63 words
The process for regeneration of metal-treating solutions as set forth in claim 6 wherein: a. said settling out of the precipitated solids removes a quantity of the metal salts substantially equal to a quantity of the metal salts dissolved from the metal being treated to maintain the concentration of metal salts substantially at a constant selected level and to permit uninterrupted metal-treating operations.
Claim 7
Dependent Claim
57 words
The process for regeneration of metal-treating solutions as set forth in claim 7 including: a. continuously measuring the density of the collected solution portion; b. recirculating the collected solution portion when the density is below a selected value; and c. mixing the precipitating agent with the collected solution portion when the density is above the selected value.