Hey guys, posting to see if anyone has come across some projects that are similar and may be able to provide some insight in to what may work.
I have been approached by a lime processing plant that want to clean up their silos and buildings. They haven’t been cleaned in years which has led to the lime dust building up and creating a strong scale over a lot of the surfaces.
They are considering repainting and then I assume keeping on top of their buildings moving forward.
I was able to kill organics present with SH. I tried; 25:1 hydrochloric acid, 8oz to 1 gallon sodium hydroxide and pressure in separate spots to try to remove the lime scale.
The chemicals sat for 5 minutes before rinsing with 1000 psi. Acid helped to remove the large caked on bits of lime but still had some scale left.
I pressure washed a section with 2000psi that had really caked on lime and it removed it pretty well but still left some scale behind too.
I would appreciate any help from someone who has dealt with a similar project.
I’ve never cleaned exactly that but I’ve cleaned plenty of stuff very similar. You can (and should) do more testing but my gut says you’ll likely need to soap it down with a 12v (or gas, air, whatever) system, allow that to dwell for 10-20 minutes while not allowing it to dry and then you’ll probably end up turbo-ing the really thick stuff. Hot water would help immensely for a project like that. When I washed drilling rigs we’d clean their mud pits which can get caked up like that and it was basically all hot water and turbos. Two machines going with three men on a rotation until the job was done. Definitely not a one man job.
They may decide to wash organics on these buildings this year then paint next year so I’d only have to clean organics off this time. These are the smallest silos on their site and I’d love to able to sort out a solution for them
Personally, I’d probably go back and spend an hour or so and try everything (within reason) in my arsenal and see what gave the best results. Then compare your top two methods time-wise and see which one works out to be the most profitable/less labor-intensive. Degreaser may be the best or maybe a high concentration of surfactant works better. Never know until you test a few different methods. One thing I can absolutely guarantee you is that hot water will make any method work better. That would be an absolute minimum if I were looking to do a job like that.
Worst case scenario is you wasted a couple hours of your time but it’s never a waste if you learn even one thing so there’s always a silver lining.
I’ve never tried to remove lime, but rust I have done. First, acid for rust. Second, they either have to encapsulate or remove the remainder of the rust and then paint as soon as possible once dry. I’d put that in my estimate so they can’t say “hey guy the rust came back” 2 months later.
Butyl on your list? I buy a couple of gallons for mixing with strippers. No, not the ones on the pole.
Hit up @Hotshot if he isn’t too busy as he is quite keen on acids, and you could tag mary the chemist but I can’t remember her chemical tag. She might pop in. I’m thinking acid and butyl, but I would whip out the turbo if things were difficult in places. You won’t hurt that metal. OVeralls and a shield.
Oh, the one variation you might want to make when testing is vary the dwell times. Acid dwell on rust in 5 minutes vs. 10 minutes makes a huge difference.
Lime is best removed by a scale remover and it has to flow over it, get changed to a non acid, and then hit with more acid…repeat the cycle until it no longer changes the acid.
My tag is CaCO3Girl……and calcium carbonate (caco3) is what you have.
