Geowizard

Crushing And Milling

35 posts in this topic

There is an effect of diminishing returns. I am sure a certain percentage is minus 200 mesh after 8 passes, but at a certain point it is dust and the hammers of the impact mill just blow the material around the inside of the mill as dust and not really accomplishing a lot more reduction in size. 

 

As noted previously in this same thread, over-crushing is a problem to be avoided.

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I have a chain impact mill that is run dry. Front plate is spaced away from the housing to allow sized particles to fall out. I want to add some water to the process to get a slurry going but don't know where to put the outlet location on the mill. Any suggestions?

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Does anyone know about a milling process called "Ryerson" or "Eureka" that was used in the 1860's and 70's? It was a dry stamp process that was followed by introduction of "pea sized ore" to ball mills. Used in some of the top producing mines in Mariposa County at the time, but I can't find anything on the specifics of the process such as stamp drop sequence, DPM ( drop per minute), etc. Al that I do know is that the ball mills used 1 to 2 inch diameter crushing medium.

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Hydrocyclone classification methods for very small scale milling operations.

 

I would like to present this topic for discussion and would like to hear from anyone with hydrocyclone design or operation experience.

In an effort to drastically reduce the amount of slime on my lab sized shaker table, I have setup 2 small primary cyclones in series (plus a 3rd fine silt removal cyclone to enable recirculating the overflow water ) for the removal of slime and reduction to primarily
sulfide and heavy metal concentrates.

 

The following images show a circulating induction point for the -50 to 100 mesh  dry classified milled quartz / slate into a venturi  powered by the intake pump running between 5-10 GPM. This thin slurry is fed into the larger cyclone (low pressure) constructed with a 15 gal cone tank and yields an underflow ideally outputting all of the metals and sulfides. The overflow of that larger cyclone is sucked into a smaller unit constructed with a typical woodworking vacuum cyclone modified with a lower cone addition.

That output can yield some very fine mesh sulfides but mostly the slime that I do not want on my table.

I am recirculating all of the water used in this closed 200 gal system so I have added a small commercial 50 PSI cyclone at the end to clean the overflow of this stage.

 

The system uses two 1.5 HP electric irrigation pumps and works well for use it was designed for.  A five gallon bucket of milled material can be fed in thirty minutes with ease and excellent results. Underflow is deposited in specially designed buckets with no loss of the desired concentrates.

 

I realize that the entire overflow of a cyclones is normally fed to a slime deck table and the underflow cycled back for additional milling
but I needed to eliminate the separate slime deck so I would welcome any comments or questions and hope that some suggestions may follow as well.

 

Thanks.

 

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post-18643-0-16615000-1462911129.jpgThanks Rick and GA 

Its definitely a mill  No balls though. They were using the ore itself as a media. Its loaded with big chunks and rounded river rock Here is a pic

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It would be called a ball mill even where the ore itself is used as the crushing media. Bigger chunks of ore will roll around and break up smaller stuff as the big chunks themselves break up. Some early ball mills were poorly designed. Modern mills will have a replaceable steel liner. A brick liner would not last very long under the abrasive conditions of rock crushing.

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