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EC number: 231-104-6 | CAS number: 7439-95-4
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data
Biotransformation and kinetics
Administrative data
- Endpoint:
- biotransformation and kinetics
- Type of information:
- experimental study
- Adequacy of study:
- supporting study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: Well documented study which meets basic scientific principles
Data source
Reference
- Reference Type:
- other company data
- Title:
- Unnamed
- Year:
- 2 010
Materials and methods
Test guideline
- Qualifier:
- no guideline followed
- GLP compliance:
- not specified
- Type of medium:
- other:
Test material
- Reference substance name:
- Magnesium
- EC Number:
- 231-104-6
- EC Name:
- Magnesium
- Cas Number:
- 7439-95-4
- Molecular formula:
- Mg
- IUPAC Name:
- magnesium
- Test material form:
- solid: compact
Constituent 1
Results and discussion
Any other information on results incl. tables
Magnesium is the eighth most abundant element and constitutes about 2% of the Earth's crust, and it is the third most plentiful element dissolved in seawater. Although magnesium is found in over 60 minerals, only dolomite, magnesite, brucite, carnallite, and olivine are of commercial importance. Magnesium and other magnesium compounds are also produced from seawater, well and lake brines and bitterns. ; Magnesium compounds, primarily magnesium oxide, are used mainly as refractory material in furnace linings for producing iron and steel, nonferrous metals, glass, and cement. Magnesium oxide and other compounds also are used in agricultural, chemical, and construction industries. Magnesium metal's principal use is as an alloying addition to aluminum, and these aluminum-magnesium alloys are used mainly for beverage cans. Magnesium alloys also are used as structural components of automobiles and machinery. Magnesium also is used to remove sulfur from iron and steel.
(i) Action of oxygen or air
Magnesium does not react with dry air but slowly gets tarnished in most air due to the formation of a thin film of the oxide, MgO. It burns in oxygen or air with a dazzling light.
Δ
2Mg + O2 ——→ 2MgO
(ii) Action of CO2 and SO2
Because of its great affinity for oxygen magnesium keeps on burning even in CO2 or SO2.
Δ
2Mg + CO2 ——→ 2MgO + C
Δ
2Mg + SO2 ——→ 2MgO + S
(iii) Action of nitrogen
On heating magnesium combines with nitrogen to form magnesium nitride.
3Mg + N2 ——→ Mg3N2
Thus when magnesium burns in air both the oxide and the nitride are formed.
(iv) Action of halogens
Magnesium on heating with halogens readily forms the halides e.g.
Δ
Mg + CI2 ——→ MgCI2
(v) Action of water
Magnesium does not decompose water in cold but decomposes boiling water or steam.
Mg + H2O ( steam) ——→ MgO + H2
(vi) Action of Acids
Dilute acids reacts with magnesium to produce dihydrogen.
Mg + 2HCI ——→ MgCi2 + H2
Mg + H2SO4 ——→ MgSO4 + H2
(dil)
Mg + 2HNO3 ——→ Mg ( NO3)2 + H2
However with conc. H2SO4, SO2 is produced
Mg + 2H2SO4 ——→ MgSo4 + SO2 + 2H2O
(conc.)
(vii) Reaction with alkyl halide
Magnesium reacts with alkyl halides in dry ether to form covalent compound called Grignard reagent.
Dry ether
Mg + C2H5I ——→C2H5MgI
Magnesium occurs as magnesite MgCO3, dolomite CaMg(CO3)2, Epsomite (MgSO4.7H2O) and carnalite K2MgCl4.6H2O and langbeinite K2Mg2(SO4)3 deposits. The chloride and sulphate of magnesium occurs in sea water from which it being extracted on an increasing scale.
Extraction
(a) From magnesite or Dolomite
The ore is first calcined to form the oxide
MgCO3 → MgO + CO2
CaCO3.MgCO3 → CaO.MgO + 2CO2
The metal is obtained from the oxide or the mixed oxides as follows:
(i) From MgO:
The oxide is mixed with carbon and heated in a current of chlorine gas.
MgO + C + Cl2 → MgCl2 + CO
The chloride thus obtained is subjected to electrolysis.
(ii) The mixed oxides [CaO.MgO] obtained from calcination of Dolomite [CaCO3.MgCO3] are redcued by ferrosilicon under reduced pressure above 1273 K.
2CaO + 2MgO + FeSi → 2Mg + Fe + Ca2SiO4
(b) From Carnallite
The ore is dehydrated in a current of hydrogen chloride and the mixture of fused chloride is electrolysed.
(c) From Sea water
Sea water containing magnesium chloride is concentrated under the sun and is treated with calcium hydroxide Ca(OH)2. Mg(OH)2 is thus precipitated, filtered and heated to give the oxide.
The oxide so obtained is treated as in (a) (i) above and then electrolysed.
Electrolysis of Magnesium Chloride
MgCl2 obtained by any of the above methods is fused and mixed with additional mixture of NaCl and CaCl2 in the temperature range of 973 – 1023 K. The molten mixture is electrolysed. Magnesium is liberated at the cathode and chlorine is evolved at the anode.
Applicant's summary and conclusion
- Conclusions:
- Although magnesium is found in over 60 minerals, only dolomite, magnesite, brucite, carnallite, talc, and olivine are of commercial importance.
The Mg2+ cation is the second most abundant cation in seawater (occurring at about 12% of the mass of sodium there), which makes seawater and sea-salt an attractive commercial source of Mg. To extract the magnesium, calcium hydroxide is added to seawater to form magnesium hydroxide precipitate.
MgCl2 + Ca(OH)2 → Mg(OH)2 + CaCl2
Magnesium hydroxide (brucite) is insoluble in water so it can be filtered out, and reacted with hydrochloric acid to obtain concentrated magnesium chloride.
Mg(OH)2 + 2 HCl → MgCl2 + 2 H2O
From magnesium chloride, electrolysis produces magnesium.
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