Steel/iron will NOT dissolve in mercury. The standard 76 pound flask used to store mercury in commerce is made of iron.
Fascinating information. Aluminum sulphate can also be used as a flocculant to clean water. I was remiss in not acquiring a passable education in chemistry, and suffer the lack thereof.
Here in the UK it is/was used a lot for that. Many years ago one water filter station had some one set the filters wrong and the water turned every ones hair green. A few people were ill from it but fortunately only a hand full. Whilst I have not tried dissolving steel with Alum, I could see it might work but suspect it may eat away enough carbon so that the stuck piece can be removed rather then dissolve the lot. I would be a bit concerned about it reacting with the zinc in brass also though.
@G1gop it was 20 tonnes of the stuff that was dumped into the wrong tank at Camelford water treatment plant in Cornwall in 1988. The wikipedia entry for "Camelford water pollution incident" makes some grim reading because of shocking ease with which it happened and the long term health effects. @presscall one for the memory bank. Thanks. Regards John
Yes a grim incident indeed and happened far too easily 20 Tons whilst it was (in that case far too much) is not an unusual amount in the larger water treatment plants. The problem was it was added all at once. rather then a slow feed. From the wkki : 2013 final report The final report was published in April 2013, and concluded that it was unlikely that the exposure to chemicals could have caused long-term health problems. Key findings of the report include: there is no evidence that the combination of metals which occurred as a result of the incident could have caused delayed health effects there was an increase in childhood infections in the area, but this increase occurred before the pollution incident a study of cancer incidence and mortality showed that there was no increase in cancer incidence in the area after the pollution incident a dermatologist investigated skin and nail problems reported by individuals affected by the incident, and reported that the problems are similar to those experienced by the general population there is no evidence that the contaminants can cause joint or muscle pain and/or swelling, and these complaints are common in the general population a Camelford resident who died of severe cerebral amyloid angiopathy was found to have higher than normal aluminium concentrations in the brain during an autopsy. However samples from the brain of a patient with similar neuropathology but unknown aluminium exposure found similar higher than usual concentrations. Research commissioned by the coroner compared 60 postmortem brains and found no correlation between aluminium or iron concentrations and the level of congophilic angiopathy or senile plaques[11][12]
Notwithstanding the 2013 final report, I personally will never fully trust any governmental entity as having my best interests at heart. They lied, they covered it up, they were incompetent. This sort of thing is not at all unusual for those in government, so why do people then trust them with the final report? It being that they are telling people what they want to hear, that everything is just fine. That very well may be the case in fact, but I will not trust them given their record over time. I researched the subject, purchased what was necessary, and filter my own water. In other words I took responsibility for my own well being, and that of my family, instead of relying on government to act as a parent figure and do such for me.
Alum is used in Grand Canyon, Colorado River, to help drop particulates in water before filtering. The sediment is very difficult to remove otherwise.
Old Post update Recently I needed to replace the vent stud on a late model Austramax Lantern. The stud had a broken sel-lock pin that had badly damaged the threads.. I made a new stud and was drilling a 1/16" hole for the sel-lock pin when the drill snapped in the hole. I remembered this post and decided to give ALUM a try. I used Aluminium Sulphate at the rate of one table spoon to 100ml of water. I used an ethanol burner in a can to keep the liquid simmering. Here you can see bubbles rising from the drill tip in the hole. After an hour simmering the corroded drill tip fell out. The brass was not affected. Success.
@ROBBO55 Excellent update, great stuff. Can’t beat an account of personal experience to validate the theory. John
Old watchmaker's trick. Using nitric acid to dissolve broken drill bits and taps in aluminium works a treat as well! Murph
