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I appreciate your responses, but I think we're thinking of two different things. In the case of a bottle of elemental standard, the expiration date is based on transpiration of water out of the poly bottle or vaporization of a volatile element like Hg or I. I think the way I'll get around...

thread136-218042 I have done several pilot studies with VSEP filters on phosphoric acid. The goal wasn't increasing concentration, but that was a side effect. The removal of impurities causes an increase in strength of the filtrate. There is also a commercial process using membranes to make...

One of my duties is running the QC laboratory, and I need some help on determining whether to throw away several thousand dollars of elemental standards due to the expiration date. I did a purge of our analytical standards in 2007, and was throwing away stuff from the 70's and 80's. Now most...

Thanks for the great link, dcasto. Gave you a star.

Bring extra food, because you may not go home when you usually do. Be prepared to sleep in your office or car.

Thanks for the replies. The 'rust' is coming in from the ammonia supply, either during NH3 production or from the CS rail cars. It sticks to the magnetic float follower in the level sensor. As you mentioned, Montemayor, we are getting crummy ammonia, with typical 0.5% water and ~1 ppm iron in...

I am trying to improve the operation of an ammonia vaporizer in fertilizer production service. We switched ammonia providers last year, and am seeing a drop-off in vaporizer performance. The bottom of the bayonet-style vaporizer is full of water after a run, and there are significant rust...

The use of sulfuric acid in ethanol production might take off, since it is used in cellulose breakdown. The phosphoric acid fertilizer plants in the US are running near capacity, but I don't think there are any plans to increase capacity with any new plants. There are mountains of sulfur in...

Gave you a star for that one, Ed. Think you sat in on my NACE paper last month in Nashville. Alloy 31 in phos acid. Thanks for the positive feedback.

I've used pug mills for mixing, not for grinding. They are very simple mixers.

A simple vortex breaker design - build a cross out of metal plate and install inside the inlet pipe. It should be 1.5 times longer than the pipe diameter, so about 72 inches long. Let about 1/3 of it stick out into the tank, but no more than that. Doesn't matter which direction it swirls...

We've got a centrifugal pump that transfers phosphoric acid from one vacuum evaporator to another. The suction line comes off the vapor body and drops about 50 ft to the pump inlet. The suction line has a U-shaped line above and below the liquid level, and a pipe comes off the mid-point of the...

There was an article in a recent "Chemical & Engineering News" about a test whereby about 300 kg of guar gum was added to a pool to increase viscosity. The theory to be tested was that the increased drag would be offset by the increased force the swimmer could exert. Elite swimmers were able...

Many states are looking very closely at industrial byproducts being sold as fertilizer. Problems in Washington state in the late 90's were well-publisized (google "fear in the fields'). California and Washington came out with new regulations that are pretty tight on heavy metals, etc...

Yup, Water Lazer is what we use in our phosphoric acid evaporator heat exchanger tubes.

Another technique to use on your tubes is chill-shocking. This may loosen the scale so that your blasting might be more effective. The concept is to alternately heat and cool the HX - steam and water. Expand and contract the tubes.

I had a similar problem dewatering calcine tailings. A Derrick vibrating screen did a good job bumping up the % solids, and we used a flocculent to improve water clarity and get even drier filter cake. I think they are an established presence in Australia, although they manufacture in Buffalo...

What is the tube-side material you are heating up? A silica deposit is pretty hard to get into solution - only hydrofluoric acid will clean it with any speed. I have similar problems cleaning tubes fouled with a gypsum compound up to 1/8" thick. 10K won't really clean it, so we go to 40,000...

Thanks for reviving an old forum topic. Got some great answers, and another good question or two. Sometimes CaCl2 is used as road salt. I used to work at a magnesium facility that sent a waste stream of HCl to an adjoining plant that made calcium chloride. Seems to me they sold about 60% of...

Look into a Wilfley AG pump. We are using them to good sucess in sulfuric acid manufacturing service. They are not seal-less, but have an expeller design that is very good in this service. Their newer design A7 expeller is actually not as well-liked by our maintenance folks as the old AG...