Mercury (Hg) is a liquid metal used in everyday life and engineering as a working fluid of various measuring devices and electrical position relays. Due to its unique properties, as well as ease of obtaining in its pure form, mercury has become widespread. Around this metal, especially in recent times, there have been many speculations and myths, based largely on ignorance of school chemistry and physics, and not on the real properties of mercury.
Mercury is very poisonous.
Even a broken medical thermometer can cause instant poisoning. Metal mercury is as toxic as any other heavy metal (for example, copper). In the Middle Ages, alchemists even took mercury inside as “therapeutic” pills and, nevertheless, remained alive. It should be noted that when ingested in the digestive system is relatively safe metal mercury, and not its salts! The notorious “poisonousness” is due to its vapors contained in the air. At a temperature of 18 ° C, intensive evaporation of mercury begins to enter the atmosphere, the inhalation of such air contributes to its accumulation in the body from where it is no longer excreted (like other heavy metals). However, in order to accumulate a significant share of mercury in the body, it is necessary to stay in the premises for a few months or years with a serious excess of the MPC of this metal in the air.
There is so little mercury in a medical thermometer that you can not pay attention if you break it.
A mercury-sized ball with the size of a pinhead is sufficient for a medium-sized room with closed windows and working ventilation to have a mercury vapor concentration that exceeds the MPC by hundreds or even thousands of times (however, with intensive ventilation, the norm will be established almost immediately). Therefore, it is not worth neglecting a mercury spill even in small quantities.
It is possible to prevent the evaporation of mercury by storing it under a layer of water.
The solubility of mercury in water is small, but much higher than the solubility of mercury in air. Therefore, it is obvious that mercury from the aqueous solution will still evaporate into the air.
Mercury beads can be collected by vacuuming.
You can not do this at all. First, it is not very effective, since mercury has a very high density, and most vacuum cleaners simply can not remove balls from hard-to-reach places. Secondly, the air, passing through the nozzles, heats up, which leads to an even more intense evaporation of the mercury trapped in the bag, and the spread of these vapors throughout the volume of the room. In fact, a very effective “evaporator” of mercury is obtained from the vacuum cleaner. Thirdly, after such “processing” it is also necessary to throw out the vacuum cleaner.
Mercury can be poured into the sewer (toilet, sink).
This will harm you, first of all, to yourself, as mercury will simply remain at the bottom of the water seal (the pipe’s bend), from where it will evaporate back into the apartment for years. It is better just to throw the collected mercury into a street garbage container (but not a garbage disposal!).
Mercury is radioactive.
Mercury has radioactive isotopes, but they, naturally, are not used in the production of household thermometers, and indeed in all cases where it is not necessary. But for some reason, we regularly hear statements about the radiation hazard of mercury.
Mercury is expensive.
The cost of mercury has the same order as the price of other metals. The price on the market depends on the purity of the proposed mercury and the volume of the shipment. In its free sale, it is naturally not, as mercury refers to AHOV (chemically dangerous chemical substances that are accidentally disposed of). In everyday life, in order to get mercury for recycling, it is also necessary to pay the relevant organizations.
Mercury is harvested using sophisticated tools available only to specialists.
Demercurization (collection of mercury) is carried out in two stages.First, remove all visible metallic mercury by mechanical means (scooping, sweeping with a hard brush, syringing with syringe, collecting balls on scotch tape, etc.). Then chemical surface treatment is carried out (if this surface can not be removed by itself, like a carpet or top layer of soil). Of the wide range of chemical demercurizers, chloro iron (FeCl3, which radio amateurs etch printed circuit boards) is the most widely available, as well as a solution of potassium permanganate (potassium permanganate), BUT necessarily with the addition of hydrochloric acid (HCl). For commercial scale spills, mercury is used to bind mercury, which transfers mercury to sulfide.
There are special solutions that completely “destroy” mercury.
Any demercurization solution simply transfers mercury from the metallic state to the bound state (usually HgCl2 chloride). The volatility of mercury salts is much lower than the volatility in the free state, which is the basis for the chemical treatment effect (so it is always better to get rid of the contaminated surface than to process it).