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Phosphoric Acid Recovery System of the Detroit Gasket and Manufacturing Co. C. BUCKINGHAM, Metallurgist Extruded Metals Division Detroit Gasket and Manufacturing Company Belding, Michigan Detroit Gasket and Manufacturing Company's Extruded Metals Division is located on the Flat River in Belding, Michigan. In an average year it uses approximately 485 tons of 85 per cent phosphoric acid in the chemical brightening of the fabricated aluminum parts it produces. Since none of this acid is an integral part of the finished product, the entire amount, as phosphates of one type of another, is either discharged into the Flat River thereby creating a serious pollution problem or it is recovered to the extent that phosphate pollution is kept well within acceptable limits. Since continued pollution was out of the question, the company sought an economical and efficient method of recovery. After considering a number of possible approaches, the present system, suggested by H. R. Tyler of Mobil Chemical Company, was adopted as the most practical for our requirements. The system has been in operation since April 14, 1966. The essentials of the system are 1) a means for maintaining and collecting a rinse solution of approximately 30 per cent phosphoric acid equivalent content, 2) a means for concentrating the 30 per cent rinse to a solution of 70 per cent phosphoric acid equivalent, and 3) storage facilities for holding the 70 per cent solution until it is shipped from the plant. Figure 1 is a schematic arrangement of the equipment for maintaining and collecting the 30 per cent phosphoric acid rinse. This arrangement of rinse tanks is known as a cascading or counterflow system; the rinse waters flowing or cascading from tank to tank in one direction and the work loads moving from tank to tank in the opposite (or counter) direction. The arrangement allows work to travel through successively more dilute (cleaner) rinses while the more dilute rinses overflow into rinses of higher acid concentration, thus the phosphoric acid in the rinses is always moving toward the most concentrated or first rinse tank. The source of all the phosphoric acid and phosphates involved is the bright dip solution (not shown in Figure 1). This solution contains, by weight, approximately 68 per cent phosphoric acid, 3 per cent nitric acid, 45 g/1 of aluminum as aluminum phosphate and sufficient water to maintain the specific gravity at about 1.74. Even at a working temperature of 210 F the solution is somewhat viscous. As the work load of bright dipped parts is transferred from the bright dip to the first (or 30 per cent) rinse the surfaces of the parts are coated with the viscous solution containing about 68 per cent phosphoric acid. To prevent "back etching" of the chemically brightened work pieces, the transfer is effected in less than 20 seconds, allowing only limited drainage of solution. The first rinse, operated at 85 to 90 F readily removes the dragged out solution. The danger of "back etch" is eliminated and ample time for drainage of parts is allowed before transfer to the second and third rinses. - 813 -
Object Description
Purdue Identification Number | ETRIWC196770 |
Title | Phosphoric acid recovery system of the Detroit Gasket and Manufacturing Company |
Author | Buckingham, C. |
Date of Original | 1967 |
Conference Title | Proceedings of the 22nd Industrial Waste Conference |
Conference Front Matter (copy and paste) | http://earchives.lib.purdue.edu/u?/engext,14179 |
Extent of Original | p. 813-822 |
Series |
Engineering extension series no. 129 Engineering bulletin v. 52, no. 3 |
Collection Title | Engineering Technical Reports Collection, Purdue University |
Repository | Purdue University Libraries |
Rights Statement | Digital object copyright Purdue University. All rights reserved. |
Language | eng |
Type (DCMI) | text |
Format | JP2 |
Date Digitized | 2009-05-20 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Resolution | 300 ppi |
Color Depth | 8 bit |
Description
Title | page 813 |
Collection Title | Engineering Technical Reports Collection, Purdue University |
Repository | Purdue University Libraries |
Rights Statement | Digital object copyright Purdue University. All rights reserved. |
Language | eng |
Type (DCMI) | text |
Format | JP2 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Transcript | Phosphoric Acid Recovery System of the Detroit Gasket and Manufacturing Co. C. BUCKINGHAM, Metallurgist Extruded Metals Division Detroit Gasket and Manufacturing Company Belding, Michigan Detroit Gasket and Manufacturing Company's Extruded Metals Division is located on the Flat River in Belding, Michigan. In an average year it uses approximately 485 tons of 85 per cent phosphoric acid in the chemical brightening of the fabricated aluminum parts it produces. Since none of this acid is an integral part of the finished product, the entire amount, as phosphates of one type of another, is either discharged into the Flat River thereby creating a serious pollution problem or it is recovered to the extent that phosphate pollution is kept well within acceptable limits. Since continued pollution was out of the question, the company sought an economical and efficient method of recovery. After considering a number of possible approaches, the present system, suggested by H. R. Tyler of Mobil Chemical Company, was adopted as the most practical for our requirements. The system has been in operation since April 14, 1966. The essentials of the system are 1) a means for maintaining and collecting a rinse solution of approximately 30 per cent phosphoric acid equivalent content, 2) a means for concentrating the 30 per cent rinse to a solution of 70 per cent phosphoric acid equivalent, and 3) storage facilities for holding the 70 per cent solution until it is shipped from the plant. Figure 1 is a schematic arrangement of the equipment for maintaining and collecting the 30 per cent phosphoric acid rinse. This arrangement of rinse tanks is known as a cascading or counterflow system; the rinse waters flowing or cascading from tank to tank in one direction and the work loads moving from tank to tank in the opposite (or counter) direction. The arrangement allows work to travel through successively more dilute (cleaner) rinses while the more dilute rinses overflow into rinses of higher acid concentration, thus the phosphoric acid in the rinses is always moving toward the most concentrated or first rinse tank. The source of all the phosphoric acid and phosphates involved is the bright dip solution (not shown in Figure 1). This solution contains, by weight, approximately 68 per cent phosphoric acid, 3 per cent nitric acid, 45 g/1 of aluminum as aluminum phosphate and sufficient water to maintain the specific gravity at about 1.74. Even at a working temperature of 210 F the solution is somewhat viscous. As the work load of bright dipped parts is transferred from the bright dip to the first (or 30 per cent) rinse the surfaces of the parts are coated with the viscous solution containing about 68 per cent phosphoric acid. To prevent "back etching" of the chemically brightened work pieces, the transfer is effected in less than 20 seconds, allowing only limited drainage of solution. The first rinse, operated at 85 to 90 F readily removes the dragged out solution. The danger of "back etch" is eliminated and ample time for drainage of parts is allowed before transfer to the second and third rinses. - 813 - |
Resolution | 300 ppi |
Color Depth | 8 bit |
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