# GSP,s cloth filter....it really works as I found by accident



## nickvc (Aug 20, 2011)

As a single guy living on my own I try to maintain a clean and tidy environment to live in and to this end I like to have all my dirty dishes washed and drying after use...I was swilling some plates and dishes off prior to a proper wash and left one saucepan soaking to remove the cooked sauce from it and by accident the washing up cloth fell into the pan and hung over the side and left it while I made myself a cup of coffee, I could hear water running down the plug hole but couldn't see any water coming from the taps so I was a little puzzled until I examined what was actually happening. The wet cloth was syphoning the water from the pan and within half an hour the pan was half empty.
This really works and for those who need to filter stubborn solutions look up GSP,s excellent post 8)


----------



## joem (Sep 12, 2011)

I use that method instead of siphoning. 
see my acid/peroxide attempt thread


----------



## glondor (Sep 12, 2011)

I love that method as well. Works great.


----------



## bmgold2 (Mar 13, 2014)

Old thread but I just spent a long time searching for GSP's post you were talking about.

I found it in the Vacuum Filter thread on the first page.

In the same thread, Lasersteve describes the "charmin plug' technique of filtering.


----------



## goldsilverpro (Mar 13, 2014)

I haven't thought of that "wick filter" since that post in 2011. When I first discovered it, I spent a lot of time messing with different setups. One of the 1st things I tried it on was on base metals hydroxides - Zn, Cu, Ni, Fe, etc., obtained when you neutralize, with sodium hydroxide (caustic soda; lye), an acid solution (HCl, HNO3, AR, H2SO4, etc.) containing various dissolved metals,. These are fluffy, voluminous, solid, insoluble compounds that pack tight when wet and are notoriously slow to filter, whether vacuum or gravity. Since the solution containing the hydroxides didn't attack steel, I did the following experiment, which was very successful and surprisingly fast. This would likely work with any alkaline sludge or solution. With acidic sludges, use all-plastic with the same results.

The best thing I found was a filter made with 3 total pieces of steel pipe and plate. The 2 pipe pieces were ground flat on the ends. There's all sorts of ways to do this. I thought of using the top 3 or 4" of a smaller bucket for the filter ring, with some weights on it to assure sealing of the filter cloth. Anyway, if you want to duplicate it, here's what I did. Make it any size you want. The main idea is that it's heavy enough (or, maybe, clamped well enough) to seal the cloth between the plate and the ring.

1- Stand up a piece of 4" steel pipe, about as tall as a bucket, centered on the inside bottom of the bucket. This acts as the stand for the filter. The bucket catches the filtered solution.
2- Center a flat sheet of 1/8"-1/4" steel, about 8" square, on top of the vertical piece of pipe in the bucket. Call this the filter plate.
3- Cover the filter plate with a piece of polyester cloth about 6" bigger than the filter. It should hang over about 3", all the way around the filter plate. With scissors, Slit this 3" of overhang of cloth all the way around into 1" strips.
4- Center about a 6" dia X 6" high piece of steel pipe vertically on the cloth. Call this the filter ring.
5- Pour the sludge in the top pipe. The liquid will wick through the cloth, horizontally, leaving the solids on the cloth, and drip into the bucket.
6- When it has nearly stopped dripping, place a 1/4" steel circle, cut so it will fit inside the top pipe, on top of the semi-dry sludge. More liquid can be removed by pushing down, by hand or with weights.

I wonder how this would work with some sort of hydraulic pressure? Might be a patent in there someplace.


----------



## 4metals (Mar 13, 2014)

This would be great to try with the notoriously difficult to filter iron hydroxides made with caustic to drop the iron chloride out of the treated waste. For the hobby refiner with under 5 gallons of waste a day it could be the answer to dewatering the sludge. 

I would think the waste would seep out since the ring is only in place with gravity.


----------



## Westerngs (Mar 15, 2014)

4metals said:


> This would be great to try with the notoriously difficult to filter iron hydroxides made with caustic to drop the iron chloride out of the treated waste. For the hobby refiner with under 5 gallons of waste a day it could be the answer to dewatering the sludge.
> 
> I would think the waste would seep out since the ring is only in place with gravity.



It is better to neutralize waste acids with type S lime instead of sodium hydroxide. The sludges settle much faster and the solution filters much easier. Lime is also much cheaper.


----------



## 4metals (Mar 15, 2014)

I think that is because bagged lime also has Mag Ox in it. 

Still vacuum filtering it can be a mess. This wick type filter is intriguing. Especially on a small scale less than 5 gallons a day.


----------



## goldsilverpro (Mar 16, 2014)

4metals said:


> I would think the waste would seep out since the ring is only in place with gravity.


The ring (a piece of heavy-walled steel pipe) was ground flat on the bottom and it was heavy enough to affect a seal. Also, the polyester cloth was fairly thick. It sealed fine.


----------



## 4metals (Mar 16, 2014)

A ground flat pipe makes sense to seal it, I envision (from hands on experience working with some bucket refiners) a rusty old pipe stub that is laying around being used because it's close enough!


----------



## goldsilverpro (Mar 16, 2014)

I got the idea for this arrangement from a place I worked. They were dissolving silver braze in dilute nitric, in SS kettles, from SS jet engine stators by the semi-load. They then added HCl to precipitate AgCl. They generated many 100's of pounds of AgCl. The filtered and rinsed AgCl was then converted with sodium hydroxide and formaldehyde in a large vat with a Lightnin' mixer on it. 

The AgCl settled and much of the nitric solution was removed by siphoning. To filter and rinse the AgCl from the remaining nitric, they had about a 24", commercially made, round vacuum filter totally made from about 11 gauge 300 series SS. It was mounted on a sturdy stand. The filter was in 3 separate parts: (1) An open top vac chamber about 8" tall with a vacuum connector near the top and a valve near the bottom for draining the collected liquid; (2) A perforated round plate, a little larger in diameter than the bottom chamber, with a series of about 1" holes in it; (3) A 24" dia. top ring about 8" tall.

The perforated plate (2) was placed on the bottom vac chamber (1) and a very thick (1/8"-3/16"), spongy, paper filter was placed on the plate. The paper came on a roll and a square piece about 3" or 4" larger than the plate was used. The top ring was placed on the paper filter. The whole assembly was clamped together with a series of mounted SS toggle bolts (maybe 8 total), connected between the bottom chamber and the top ring, around the whole thing.

You started the vacuum and then filled the top ring with the AgCl/nitric sludge. One time, A fuse blew on the vac pump and it shut down. After I tended to the pump and then returned, I found that all the solution had wicked laterally through the filter paper and was on the floor. I cleaned up the mess with soda ash and then started thinking about what had really happened. Sort of a "eureka" moment. 

Another time, I was gravity filtering something in a plastic funnel. I hadn't trimmed the paper properly and it was sticking up a couple of inches above the funnel. I filled the funnel with solution and the top of the paper got wet and soon flopped over the top of the funnel in several places, which soon started wicking the solution onto the floor, even when the solution level in the funnel had dropped considerably. 

Thus, from those 2 screw-ups, the "wick filter" evolved.


----------



## 4metals (Mar 16, 2014)

Proof positive that good science comes from observation! 

Great job!!


----------

