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Peculiar Characteristics of Chromium Don E. Bloodgood and Aubrey Strickland Purdue University Lafayette, Indiana At the present time the principal methods for the disposal ol chromium compounds (1), (2), (3)* are (1) reduction and precipita¬ tion with various compounds with subsequent disposal by burial or dumping, and (2) precipitation and partial recovery of the desired constituents by electrolysis. These methods are said to be satisfactory in some cases. However, they cannot be considered efficient or effective in producing chromium-free water or in the recovery of valuable chromium compounds from the dilute waste waters of the metal plat¬ ing industries. Recognition of the need for a better method prompted studies at Purdue University using commercial ion-exchange resins. An ion-exchange method would eliminate the necessity for large settling tanks, large quantities of chemicals, extra personnel, etc., and in addition would afford a rapid continuous process for detoxifying wastes and recovering the chromium and perhaps other valuable com¬ pounds. Early attempts were made to treat metal plating wastes containing both chromium and cyanide compounds, but it was ultimately con¬ cluded that the complexity of each was such that separate studies of the two wastes would be more feasible. At first, tests were made with cation and anion exchangers in series, using solutions of potassium chromate. It was found that some of the chromate was removed on the cation exchanger, much more on the anion exchanger, and some was not removed at all. Sulfuric acid and hydrochloric acid of various normalities were used for regenerating the cation exchangers, and sodium hydroxide, ammonium hydroxide, sodium carbonate, hydrochloric acid, and, because of its molecular size, tartaric acid solutions were tried for regenerating the anion exchangers. In no case was the regeneration considered satisfactory, and in all cases * Italicized figures in parentheses refer to entries in the Bibliography, page 241. 232
Object Description
Purdue Identification Number | ETRIWC194923 |
Title | Peculiar characteristics of chromium |
Author |
Bloodgood, Don E. Strickland, Aubrey |
Date of Original | 1949 |
Conference Title | Proceedings of the fifth Industrial Waste Conference |
Conference Front Matter (copy and paste) | http://earchives.lib.purdue.edu/cdm4/document.php?CISOROOT=/engext&CISOPTR=10924&REC=14 |
Extent of Original | p. 232-242 |
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 | 2008-05-18 |
Capture Device | Fujitsu fi-5650c |
Capture Details | ScandAll21 |
Resolution | 300 ppi |
Color Depth | 8 bit |
Description
Title | page 232 |
Date of Original | 1949 |
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 | ScandAll21 |
Transcript | Peculiar Characteristics of Chromium Don E. Bloodgood and Aubrey Strickland Purdue University Lafayette, Indiana At the present time the principal methods for the disposal ol chromium compounds (1), (2), (3)* are (1) reduction and precipita¬ tion with various compounds with subsequent disposal by burial or dumping, and (2) precipitation and partial recovery of the desired constituents by electrolysis. These methods are said to be satisfactory in some cases. However, they cannot be considered efficient or effective in producing chromium-free water or in the recovery of valuable chromium compounds from the dilute waste waters of the metal plat¬ ing industries. Recognition of the need for a better method prompted studies at Purdue University using commercial ion-exchange resins. An ion-exchange method would eliminate the necessity for large settling tanks, large quantities of chemicals, extra personnel, etc., and in addition would afford a rapid continuous process for detoxifying wastes and recovering the chromium and perhaps other valuable com¬ pounds. Early attempts were made to treat metal plating wastes containing both chromium and cyanide compounds, but it was ultimately con¬ cluded that the complexity of each was such that separate studies of the two wastes would be more feasible. At first, tests were made with cation and anion exchangers in series, using solutions of potassium chromate. It was found that some of the chromate was removed on the cation exchanger, much more on the anion exchanger, and some was not removed at all. Sulfuric acid and hydrochloric acid of various normalities were used for regenerating the cation exchangers, and sodium hydroxide, ammonium hydroxide, sodium carbonate, hydrochloric acid, and, because of its molecular size, tartaric acid solutions were tried for regenerating the anion exchangers. In no case was the regeneration considered satisfactory, and in all cases * Italicized figures in parentheses refer to entries in the Bibliography, page 241. 232 |
Resolution | 300 ppi |
Color Depth | 8 bit |
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