AARL process as applied at SDGM. • Identify the key elution circuit components. • Demonstrate an understanding of carbon reactivation theory. • Demonstrate an. Request PDF on ResearchGate | Modelling of the AARL elution process | The influence of temperature on the equilibrium adsorption of gold and hydroxide ion . successful methods is the carbon-in-pulp (CIP) process. In CIP processing elution rig was commissioned to simulate industrial Zadra and AARL carbon elution.
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Automatic solution temperature control and column back pressure control are the minimum automation required.
The solution is heated to about deg-F and pumped through the carbon stripping vessel at a flow rate of about 2 Bed Volumes per hour. Boyle is a full bore positive displacement slurry pump. After the desorption vessel has been filled with loaded carbon and solution flow is started, the only operator attention required is periodic system checks typical of any process plant operation. High levels of gold in recycled eluant result in a reduction in stripping rate as illustrated typically by Figure 2 3.
Pressure stripping columns are normally sized with a height to diameter ratio of about 4 to 1.
AARL Carbon Stripping System Operation: Elution & Electrowinning
Control of the amount of solution purged from the system is done either on a routine scheduled basis or by monitoring stripping efficiency and bleeding as efficiency drops. The process was developed by J.
Top of column temperature ………. The presoak step is started by preheating the carbon with hot water. High quality fresh water at about deg-F is then pumped through the pressurized stripping vessel to produce the pregnant eluant.
The downflowingcondensate washes the gold values from the carbon particles into the boiler section below. USBM research indicated that increases in stripping efficiency could be achieved up to deg-F. The carbon is then steam stripped to recover residual alcohol. Additional water is forced into this line via valve AV and the carbon is forced along the line through valve AV into the elution column.
Much greater benefit would have been derived from the provision of an additional eluate tank as it is in the later electrowinning stage that most of the present hold ups occur.
Selection of design and operating flows is made on the basis of equipment costs and time constraints.
Mechanism of Catalyst Deactivation. Within a few proess, the alcohol is concentrated in the overhead condenser tank. It was not, however, until methods for chemically desorbing gold from loaded carbon were developed, that the process came into widespread use for gold recovery from ore. The sequence controller time for step 06 should then be reset to the time indicated by the graph. The solution then flows up through the bed of carbon and overflows near the top of the stripping vessel.
The mere following of the instructions given in that section will not ensure effective stripping results as there are many extraneous factors which need to be taken into account.
In this case a two compartment column is used. The acid rinse step 05 is currently set for e,ution. The stripping efficiency is virtually independent of eluant water flow rate in the range of 1 to 5 bed volumes per hour. Sodium cyanide is sometimes added to the solution but it is frequently unnecessary.
Carbon Stripping – Denver Mineral Engineers
Eluant water temperature has a very significant effect on stripping efficiency. Part 3 outlines in full detail every action required on the part of goldroom personnel in order to operate the plant successfully. The micron eluted carbon also appears to have a somewhat higher level of activity than carbon eluted by other methods.
Glycols are generally used, rather than alcohols, because they are virtually uninflammable.
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With the AARL process, elution is normally proceeded by acid washing the carbon. The process generally takes about 48 to 72 hours. This necessitates larger carbon inventories and larger equipment than other faster processes. In any case the potable water system here does not cater for the running aarrl both steps at the same time.