Dust manganese

Aqueous solutions of hydrogen peroxide decompose slowly the decomposition is catalysed by alkalis, by light and by heterogeneous catalysts, for example dust, platinum black and manganese... 

Exposure to manganese dusts, fume, and compounds should not exceed the ceiling value of 5 mg/ms for even short periods because of the element s toxicity level. 

Health and Environment. Manganese in trace amounts is an essential element for both plants and animals and is among the trace elements least toxic to mammals including humans. Exposure to abnormally high concentrations of manganese, particulady in the form of dust and fumes, is, however, known to have resulted in adverse effects to humans (36,37) (see Mineral nutrients). 

Modification of the burning rates, pressure exponents, and temp coefficients of burning rate of the fluorocarbon composites has been accomplished with copper, lead, tin, sodium, ammonium and potassium fluoborates sodium, potassium, lithium, lead, copper and calcium fluorides potassium and ammonium dichromate lead and zinc stearate cesium carbonate potassium and ammonium sulfate copper chromite oxides of magnesium, copper and manganese boron zinc dust and carbon black (Ref 75)... 

Powdered manganese combusts easily in air and burns very quickly. It forms dust suspensions in air, giving rise to explosive mixtures. 

Dusts of magnesium, zirconium, titanium and some magnesium-aluminium alloys [1], and (when heated) of aluminium, chromium and manganese [2], when suspended in carbon dioxide atmospheres are ignitable and explosive, and several bulk metals will bum in the gas. 

In a factory manufacturing organo-iron and organo-manganese catalysts, use of cotton waste to mop up a spill of dilute hydrazine solution led to a spontaneous fire later. The fire was attributed to onset of rapid metal-catalysed decomposition of the hydrazine after sufficient water had evaporated from the waste, the traces of heavy metals originating from dust contamination, etc. 

The finely divided metal is pyrophoric, and a mixture of manganese and aluminium dusts accidentally released from a filter bag exploded violently. 

Solutions to similar problems of achieving catalytic turnover [22] in McMurry couplings [23], Nozaki—Hiyama reactions [24], and pinacol couplings [25] have been reported by Fiirstner and by Hirao. The key step in these reactions is the in situ silylation of titanium and vanadium oxo species with Me3SiCl and reduction of the metal halides by suitable metal powders, e. g. zinc and manganese dust, as shown in Scheme 12.13. 

Technetium and rhenium differ markedly from manganese, but they are very similar to each other. They have little cationic chemistry, few compounds in the oxidation state II, more extensive chemistry in the IV and V states. The metals resemble Pt in their appearance (usually, however, they are in the form of a grey powder) they tarnish slowly in moist air, do not react with water. Metal dust is a fire and explosion hazard. 

In the other study. X-ray fluorescence spectroscopy was used to analyze trace element concentrations by observing dusts on 37 ram diameter cellulose acetate filters (20). Twenty-three elutriator and twenty-three area samples from 10 different bales of cotton were analyzed. The average fraction of total dust accounted for by the elements analyzed was 14.4% amd 7.6% for vertical elutriator and area samples, respectively. Although the variation in absolute quantity of atn element was high, the relative abundance of an element was consistent for measurements within a bale. Averaged over all the samples analyzed, calcium was the most abundant element detected (3.6%), followed by silicon (2.9%), potassium (2.7%), iron (1.1%), aluminum (1.1%), sulfur (1.0%), chlorine (0.8%) and phosphorous (0.6%). Other elements detected in smaller aunounts included titanium, manganese, nickel, copper, zinc, bromine, rubidium, strontium, barium, mercury amd lead. 

The dust and fumes from the powder form of most manganese compounds, especially the oxides, are very toxic to plants, animals, and humans. Even inhaling small amounts is toxic. The powder form of manganese metal is flammable, and manganese fires cannot be extinguished with water. They must be smothered by sand or dry chemicals. 

In a report of five cases of manganism in a steel plant, three resulted from exposure to ferromanganese fume and two from exposure to ferromanganese dust. As indicated above, ferromanganese fume is primarily manganese tetroxide. Two of the workers exposed to the fume worked in a pig casting operation where the exposure was estimated to have been 13.3 mg/m for 5 years. 

Inhalation of manganese tetroxide dust can lead to an inflammatory response in the lung. Symptoms may include cough, bronchitis, pneumonitis, and occasionally pneumonia. It has been noted that this type of inflammatory... 

It is generally held that manganese fume is more hazardous than equivalent concentrations of manganese-containing dust. 

Although trace amounts of manganese are essential for animals, in large quantities the metal can cause acute and chronic poisoning. Chronic inhalation of metal dust or fumes can cause manganism, a nonfatal disease affecting the central nervous system. The symptoms are mental disorder and disturbance in speech. 

The form of nickel in particles from different industries varies. The mineralogical composition, chemical content, and form of dusts from nine industries in Cracow, Poland, were examined (Rybicka 1989). The chemical form of a particle-associated heavy metal that was assessed by a five-step extraction scheme classified the metal as exchangeable, easily reducible (manganese oxides, partly amorphous iron oxyhydrates and carbonates), moderately reducible (amorphous and poorly crystallized iron oxyhydrates), organically bound or sulfidic, and residual. Dusts from power plants had a silicate characteristic with quartz and mullite predominant. Approximately 90% of the nickel from these... 

Cooper and Watson (21) reported finding about 0.1% manganese in both the fine (<2 pm) and coarse ( 2 pm) particle fractions, respectively, of urban dust in Portland and 0.2% and 0.085% in the fine and coarse fractions, respectively in continental dust. Thus, it should be possible to use this element in RSP samples as a soil tracer in New York City. However, during part of the period of this investigation, methylcyclopentadienyl tricarbonyl (MMT) was used as an octane booster for unleaded gasoline ( ). ... 

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