Recovering Silver from Crushed Ore?

[solarsmith]

ok first of all look up a company called Hazen Research. they are located in golden Colorado and have a staff of about 200 people. they can answer your question about the best way to get the values out of your ore. It is what they do. you want all the values out of your ore and your interested in doing some sort of an acid leach.
it may work but if you do not concentrate first you will spend a lot more on acids than the values will pay for. your ore sounds hot and I hope you have lots of it .
if it is of a sulfide type hazen will probably recommend a froth flotation system as part of the concentration process. this will automatically recover most all of the silver and other values that might be in the ore. Hazen is very good at telling you what other values might be in it for you. Tell them what scale your able to dig 100lbs a day or 100 tons a day. they can and will recommend the best system for you. and if you like they will set up a small scale test plant for you. My thoughts are that if you have ore as rich as you say then it should be very easy to set up a concentration system to get it over 200 to 300 oz pgms per ton on your own. if this is even close to to what you can get then the next step is very easy smelt it or sell it to a smelter. have them send you a bar and then you can soak it in acid to your hearts content. and learn the chemistry to make your pregnant acid back into pt ag and au and cu . there are a 100 paths from ore to bar. Bryan in Denver CO 303x503x4799.

 

[shrewdly]

First things first. You can take your raw ore and extract your gold & silver - anything is possible. Possible yes, profitable no. Although gold and silver can occur in native form (metallic) in most ores they locked into other minerals commonly the sulphide minerals. You should pre-concentrate your ore prior to trying to extract the precious metals, otherwise you're just wasting a lot of chemical. Concentrating your ore can reduce the volumes you treat by anywhere from 10:1 to 30:1. There are various techniques available to the small scale miner for producing a concentrate. Froth flotation is an excellent process that can obtain recoveries in excess of 90 percent of the contained minerals, however it is capital intensive usually requiring crushing , grinding and flotation as well as filtration. In your case I would suggest a gravity process. This would involve crushing your ore down to minus 80 mesh. You can find several types of equipment to do the separation - a sluice box, a shaker table, a jig, spirals etc... With gravity concentration techniques you're separating material by their differences in density (the lights from the heavies). The key parameter here is particle size you want them to be small (-80 mesh) and of the same size. A roller crusher produces the most uniform product and would be best for a gravity plant. The simplest and oldest gravity device is the sluice box, it can be made easily in various sizes, can handle large volumes and if set up properly can achieve high recoveries. The shaker table is another device that works quite effectively and I've seen tables do a very clean separation with distinct bands of the various minerals coming off the table. The major drawback to a table is it's limited throughput, a 3 ft. by 4 ft. table can process about 1000 - 1200 lbs. per hour. A jig can be effective but it requires a lot of water and a solid foundation. You should not discount the value of the base metals as their value could pay for your operating costs with the gold and silver as straight profit. It would probably be best if you produced a concentrate and just sold it to a smelter.
An excellent report on sluice box design and operation was written by Randy Clarkson P.Eng for the KPMA (Klondike Placer Miners Association). His design suggestions resulted in improvements in sluice box recoveries from 60 - 75 percent to 90 - 100 percent. If you go to the http://www.gpex.ca website you'll find an article by Gary Weisphaut on shaker table design and construction. There are various manufacturers and suppliers of small crushers out there. There is even one who manufactures a jaw/roller combination rated at a tonne per hour.

Good luck and may all your endeavours be golden