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Crud Formation in Copper SX (11 replies and 2 comments)
The presence of solids in the feed solution.
Treating ores may lead to the presence of humic acids, which also cause crud formation.
Clay treatment might be one of the solutions.
We specialize in recovery organic from crud using FlottwegTricanter centrifuges, and normally the crud consists predominantly of solids from the PLS. The crud takes on a gel-like consistency when flocculent is overdosed in the PLS clarifiers. There is also quite a lot of windblown dust in some plants. In some tropical areas we also get an abundance of insects in the crud, being attracted by the smell and the lights.
Hi, we used Flottweg Tricanter centrifuge for recovering organic from crud. But only 6 to 8% of organic recovered from crud. By the way, we dont have any additional step for crud. We just pumped crud from SX and feed Flottweg. is this the main reason that we cant recover much organic?
As all mentioned, we should protect settler and PLS pond areas. Is it logical that these areas be closed? For example, have roof?
Normally, all settlers have a roof, either a single general cover or sectioned covers.
Regarding PLS ponds is more difficult cover them for their great size, though, already have been developed some ideas to cover them and prevent evaporation and dust pollution (especially in desert zones).
I remember two practices in a SX plant.
Desandling ponds. That help to decrease the solid content in PLS, decrease Crud formation and.
A 1 mm of vinyl Manta covers in PLS ponds to avoid the evaporation.
In agitated leach process, we use the pin bed clarifiers after the thickener to decrease the amount of solid in our PLS.
Silica is also a common component of crud. You could analyse your PLS to see how much Si is present and try to remove some of this ahead of the SX circuit by control of upstream precipitation conditions, etc. or control the solution conditions to ensure that the silica remains in the most manageable form.
As said by everybody, cruds are forming by solid in PLS, so it most important to control overflow clarifier TSS, before sending in PLS pond etc.
As said in all the above comments... control the level of your tss (total solid suspended) in your PLS and electrolyte stream, a max of 50 to 100 ppm can be allowed (as for most of the plant in a copper belt Africa).
Controlling TSS can be a little difficult given the economics of the process and the composition of the ore body. A simpler way is to run the strippers organic continuous while running extractors in aqueous continuity. This way all the crud will pack in the strippers from where it can be pumped out using diaphragm pumps and further treated using a system such as a Tricantor or a clay treatment/filter-press operation.
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What are main problems in copper SX that cause to crud forming? Apart from the solid content in the PLS solution. I know a little bit of crud in not dangerous 4- 5 centimetres in the settler. I hear italso helps coalescence phenomena, but over 10 cm is not good. What else?