Water based Sulphuric acid based pickling system for Copper and Copper alloys to remove oxides and Brighten Brass.
Used in Mill Rolling after annealing process.
Spray or soak and works with high speed operation as well.
ACIDON 7710 is Engineered and formulated for the pickling of copper and copper alloys.
7710 will remove cuprous (red) oxide and other oxides, which would be left by the simple sulfuric acid pickle used to remove cupric black, oxide scale. The use of 7710 introduces no foreign metals to the bath, thereby, greatly simplifying waste treatment and copper recovery. The principal by-products of the reaction are CuSo4 and water.
The pickling rate with 7710 depends only on the 7710 concentration and pickling solution temperature. The build-up of copper does not effect pickling rates in any way until the bath is saturated with cupric ions.
Recovery Recovery Recovery Recovery Recovery – This method recovers copper as Cu(No3),3 the purity being dependent upon the quality of the acid used and what alloys are pickled.
Crystallization is adaptable to continuous operation and can be concentrated. This recovery method takes advantage of the decrease in copper sulfate solubility with decreasing temperatures. For any but small operations, the use of external cooling (cold water coils, for example) in the crystallizing vessel is necessary.
The use of a centrifugal filter on a continuous basis is suggested for large scale installations. Centrifugal filters can produce a relatively dry salt.
Recovery – this method of copper recovery has the advantage of recovering copper as metal and regenerating the acid in the process. Electrolytic recovery of copper from 7710 solution is quite simple. Contact General Chemical for suggestions on electrolytic recovery relative to your specific plant application.
COPPER AND COPPER ALLOY PICKLING BATH OPERATING PARAMETERS
In solution, various compositions are possible, depending upon the particular requirement and the alloy to be picked. A typical 7710 bath is as follows,
ACIDON 7710 concentration 10 – 20% v/v
Temperature 90 – 115° F (32 – 46)° C
BATH PREPARATIONS :
- Sequence of Additions
The pickling solution should always be prepared by first adding the 7710 to cold water, mixing thoroughly and allowing the mixture to cool below 140° F.
- Pickling Temperature
The 7710 pickling bath can be used at ambient temperatures to 120° F (49° C)(Do not exceed 140° F (60° C). The higher temperatures give higher pickling rates. The most commonly used temperature range is 90 – 110° F (32-41° C). For greater economy, let the pickling solution cool to ambient temperature when not in use for prolonged periods (8 hours or longer).
- Immersion Time
The immersion time is dependent upon (1) the amount of scale to be removed, (2) the pickling temperature, (3) the alloy being pickled, and (4) the surface finish desired. As a rule, a spray application needs shorter time. Over pickling usually results in a matte finish.
- Suggested Process Sequences
The most economical method of operating a pickle is to use a metering system for 7710 additions. This is particularly easy with pickling operations which remove the same general type of scale and have a predictable work load. It is then possible to operate at a steady state concentration, with 7710 being added at the same rate as it is being consumed in pickling.
For batch systems, it is necessary to perform occasional, simple, chemical analysis to determine the 7710 concentration and to make the appropriate additions of 7710. The frequency with which this is required will be determined primarily by the work load processed and the tank volume.
It is necessary to make some provision for temperature control; cooling will normally be required to control temperature rises caused by the introduction of hot metal, either from a hot pre-pickle or, in some cases, directly from an annealing operation. Cooling may also be required if large surface areas are to be pickled in relatively small solution volumes. This is primarily necessary to avoid temperature rises, which result in over pickling.
Prolonged operation at temperatures above 140° F will result in accelerated metal losses and will cause unnecessary costs.
SUITABLE MATERIALS OF CONSTRUCTION
For 7710 pickling tanks and other equipment to be used in contact with the pickling solution itself, the following materials have been found suitable:
- 300 Series Stainless Steels
In case of contact, immediately flush eyes with plenty of water for at least 15 minutes. Get medical attention. Flush skin with water. Wash clothing before reuse. Refer to the appropriate Material Data Safety Sheet.
HANDLING AND STORAGE
Store in original closed container. Do not tamper with vent. Keep bungs in and unobstructed. Keep out of sun and away from heat. Store in a clean, cool area. Do not add any other product to this container. Empty drum completely. Never use compressed air to empty. When empty, rinse thoroughly with clean water. Use plastic valves only.
Note: The information presented herein is our interpretation of certain test results and field experience to date. The information is not to be taken as warranty or representation for which we assume legal responsibility, nor as permission or recommendation to practice any patented invention without a license. It is offered solely for your consideration, investigation and verification.