What is Cobalt? Why do we add Cobalt ? what is it good for?
When drilling hard material, the friction between the drill and the material we are drilling produces very high temperature. So high temperature may damage the drill or the material we are drilling. Cobalt increases the strength of the steel this makes the drill more so the friction doesn’t produce high temperatures.
It is alloyed with iron, nickel and other metals to make Alnico, an alloy of unusual magnetic strength with many important uses. Stellite alloys, containing cobalt, chromium, and tungsten, are used for high-speed, heavy-duty, high temperature cutting tools, and for dies (Cobalt Development Institute, 2004).
Cobalt metal has three major uses in the petrochemical and plastic industries as both heterogeneous and homogeneous catalysts: (1) hydro-treating and desulfurization catalysts for oil and gas; these catalysts are typically 3–5% cobalt oxide (Co3O4), 14% manganese trioxide (MnO3), and the balance aluminium oxide (Al2O3); (2) mixed cobalt acetate/manganese–sodium bromide homogeneous catalyst for the production of terephthalic acid and dimethyl terephthalate; and (3) cobalt catalyst in the oxo synthesis (hydroformylation) for the production of alcohols and aldehydes for plastic and detergent production, employing freshly reduced cobalt metal, carbonyls, or cobalt salts (transformed in situ to carbonyl) (Cobalt Development Institute, undated b; USGS, 2005).
Cobalt is a brittle, hard metal, resembling iron and nickel in appearance. It has a metallic permeability of about two thirds that of iron. Cobalt tends to exist as a mixture of two allotropes over a wide temperature range. The transformation is sluggish and accounts in part for the wide variation in reported data on physical properties of cobalt.
Cobalt is a metal found naturally in soil, dust, and seawater. It is usually found in association with nickel. Cobalt is a brittle, hard metal, resembling iron and nickel in appearance. It has a metallic permeability of about two thirds that of iron. Cobalt tends to exist as a mixture of two allotropes over a wide temperature range. The transformation is sluggish and accounts in part for the wide variation in reported data on physical properties of cobalt.
Cobalt is a relatively rare magnetic element with properties similar to iron and nickel. The two valance states are cobaltous and cobaltic and the former is the most common valance used in the chemical industry. Cobalt occurs in nature primarily as arsenide’s, oxides, and sulfides. Most of the production of cobalt involves the metallic form used in the formation of cobalt super-alloys. The term “hard metal” refers to compounds containing tungsten carbide (80–95%) combined with matrices formed from cobalt (5–20%) and nickel (0–5%).
Everyone is exposed to cobalt at low levels in air, water, and food. People who live near hazardous waste sites containing cobalt may be exposed to higher levels of this chemical. Food is another source of exposure to cobalt. The largest source of exposure to cobalt for the general population is the food supply. The estimated intake from food is 5–40 µg/day, most of which is inorganic cobalt. Occupational exposure to cobalt occurs in several industries. Levels of cobalt in tobacco range from <0.3 to 2.3 µg/g dry weight, and approximately 0.5% of this cobalt is present in mainstream smoke. Cobalt concentrations in coal, crude oil, fuel oil, and gasoline in the United States were found to be 5 mg/kg, 0.001–10 mg/kg, 0.03–0.3 mg/kg, and <0.1 mg/kg, respectively.
Inhalation of cobalt particles results in deposition in the upper and lower respiratory tract, where they can be retained or absorbed into the blood after dissolution or mechanically transferred to the gastrointestinal tract by mucociliary action and swallowing. Approximately 50% of the cobalt that enters the gastrointestinal tract will be absorbed. Cobalt absorption is increased among individuals who are iron deficient. Water-soluble forms are better absorbed than insoluble forms. Total body burden is estimated as 1.1–1.5 mg, with 0.11 mg in the liver.
No studies describe the distribution of cobalt in humans following ingestion, but animal studies indicate that cobalt is retained primarily in the liver. In a controlled human aerosol exposure study, 40% of the initial lung burden of cobalt oxide was retained at 6 months after exposure.
Did you know that Cobalt has also been used as a treatment for anemia? Cobalt causes red blood cell production
Did you know that Cobalt can stay for years in water and soil? It can move from the soil to underground water. Plants take up cobalt from the soil. OSHA exposure limit: 0.1 0.1mg/m³ for cobalt in workplace air for an 8-hour workday, 40-hour work week. American Conference on General and Industrial Hygiene (ACGIH) occupational exposure limit: 0.02 mg/m³ for cobalt for an 8-hour workday, 40-hour workweek. National Institute for Occupational Safety and Health (NIOSH) occupational exposure limit: 0.05 mg/m³ for cobalt for a 10-hour workday, 40-hour workweek.
Measured atmospheric concentrations of cobalt are about 1 ng/m3 or less in non-source areas and generally less than 10 ng/m3 in source areas, although higher concentrations in source areas have been reported. Surface water and groundwater concentrations of cobalt are low, below 1 µg/l in pristine areas and 1–10 µg/l in populated areas. Surface water and groundwater concentrations can be much higher in mining and agricultural areas — as much as several hundred milligrams per litre. Mean cobalt concentrations in seawater have been reported to be less than 1 µg/l. Cobalt concentrations in drinking-water are generally <1–2 µg/l. In rainwater, mean concentrations are 0.3–1.7 µg/l. The earth’s crust contains an average cobalt concentration of 20–25 mg/kg. Near some anthropogenic sources, the concentration of cobalt in soil may be several hundred milligrams per kilogram.