Precautions mercury

Precautions Mercury is highly toxic by skin absorption or breathing of fumes. 

Isocyanates toxic hazards and precautions Mercury — health and safety precautions Toxic substances a precautionary policy Antimony — health and safety precautions Phosphine — health and safety precautions Carbon dust — health and safety precautions Ventilation of the workplace Anthrax health hazards Oust and accidents in malthouses Cotton dust sampling... 

When exhausting desiccators, a filter flask trap (see Fig. 77, 19, 2) should always be inserted between the desiccator and the pump. The vacuum should be applied gradually and should not exceed about 50 cm. of mercury for models (a), (6) and (d). These desiccators may withstand lower pressures, but it is generally considered unsafe to exhaust below this pressure unless the precaution be taken of surrounding the desiccator by a cage of fine-mesh steel wire collapse of the desiccator will then do no harm.J Models (c) and (e) may be exhausted to about 20 mm. of mercury a steel wire cage must be provided for this low pressure. 

Environmental awareness is a prime concern in all KOH plants. Safety precautions required in KOH and chlorine operations are well documented in operating manuals and sales brochures pubUshed by all commercial producers. Discharges of waste effluents containing mercury are strictly forbidden. 

This method is used for the determination of total chromium (Cr), cadmium (Cd), arsenic (As), nickel (Ni), manganese (Mn), beiylhum (Be), copper (Cu), zinc (Zn), lead (Pb), selenium (Se), phosphorus (P), thalhum (Tl), silver (Ag), antimony (Sb), barium (Ba), and mer-cuiy (Hg) stack emissions from stationaiy sources. This method may also be used for the determination of particulate emissions fohowing the procedures and precautions described. However, modifications to the sample recoveiy and analysis procedures described in the method for the purpose of determining particulate emissions may potentially impacl the front-half mercury determination. 

Table 5.40 Routine laboratory precautions with mercury...

The mercury reservoir is then lowered until the mercury flow just ceases (not further) and the electrode is allowed to stand in the air. It is good technique, at the beginning of each period of use, to immerse the capillary for ca 1 min. in 1 1-nitric acid while mercury is flowing, then wash it well with distilled water a further precaution is to allow the mercury drops to form in distilled water for about 15 minutes. 

The method used to dissolve samples may have an important impact on the quality of the data for some elements. Obviously, if the sample has not been fully dissolved, then quantification will give less than the true yield for some or all elements. Some individual elements may also form insoluble species or complexes during dissolution (e.g., Sn, Cr), and special precautions are necessary to ensure that such complexes are dissolved. Mercury in solution will often be absorbed onto the surface of glass vessels. Quantification will also be less than expected where volatile elements or their compounds are lost a process which may be aggravated if heating in an open vessel. 

Unfiltered light from mercury lamps is damaging to the eyes suitable precautions, such as wearing appropriate glasses and surrounding the reaction vessel with aluminum foil, should be taken,... 

For the pumping of large quantities of gas in this pressure region, vapor ejector pumps are by far the most suitable. With mercury vapor ejector pumps, completely oil-free vacua can be produced. As a precaution, the insertion of a cold trap chilled with liquid nitrogen is recommended so that the harmful mercury vapor does not enter the vessel. With the medium vacuum sorption traps described under a), it is possible with two-stage rotary vane pumps to produce almost oil-free vacua down to below 10" mbar. 

It is important to note that if the mercury surface be charged the extent of adsorption will he very materially affected (see Oh. vii). Lack of this precaution has vitiated the conclusions derived from a number of experiments, see ante, p. 36. 

CAUTION Mercury(II) acetate [Hg(OAc)2] is highly toxic and may be fatal if ingested, inhaled, or swallowed. It is moderately toxic by skin contact. Appropriate safety precautions and procedures should be taken during all stages of its handling and disposal. 

There are two types of U-tube manometer the open-ended manometer is obviously inconvenient for low pressure measurements if an organic liquid of low vapour pressure is used instead of mercury. The small U-tube with one sealed end is the most common and convenient form. The sealed end is closed whilst the tube is under a good vacuum (p < 10 Torr) and, provided that precautions are taken to preserve the vacuum, the pressure in this reference space (the Torricelli vacuum) can be neglected when calculating the measured pressure. 

When a vacuum is used to outgas, precautions must be taken to prevent the initial surge from blowing powder throughout the system. In a well-sealed system outgassing can be taken as completed when no pressure increase can be detected after isolation from the pump. For routine work generally 10 to 10 torr (mm of mercury) is sufficient. The usual precautions, such as a baffle and a cold trap, should be taken to ensure no contamination by the pump oil. 

The rapidity with which sulphuric acid decomposes potassium chlorate is well known. If small quantities of the salt are treated with the acid, with the precaution of fusing the salt in the retort and, when cold, pouring sulphuric acid on the mass, the violence of tho reaction is rednced, and, at a convenient temp., a gas is disengaged which can be collected over mercury, and which is designated deutoxide of chlorine. The residue in the retort contains potassium sulphate, and sparingly soluble unknown salt of a new acid (perchloric acid). 

If you have been poisoned by an arsenic or mercury compound, or byacyanide, immediately see a physician. The precautions to be taken when working with other poisonous substances are indicated in the relevant sections of the book. 

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