Corundum
Classification:
Corundum is an important Al ore.
Cas:
1302-74-5
Synonyms/Trade Names:
Emery, EN 237, KER
710, MP 1 (Refractory), Rubin, Saphir, Smirgel, Tonerde.
Chemistry/Composition:
α-Al2O3 . It sometimes contains Fe3+ .
Structure:
Oxygen atoms are located approximately in an almost hexagonal packing, two-thirds of all possible octahedral positions are occupied by Al atoms.
Crystallographic Constants:
4.760 4.760 12.98 60.000 60.000 60.000.
Crystal Group:
Trigonal.
Color:
White to gray, blue, red, yellow, and green.
Optical Properties:
nO=1.767-1.772 nE=1.759-1.763.
Pleochroism:
colorless to blue or yellow.
Powder Diagram:
2.09 2.55 1.60 3.48 (10-173).
Natural Sources:
World-wide.
Medical Importance:
Key Hazards:
Fibrogenic, intoxication, asthmaticlike reaction, neurotoxicity.
Involved Organs:
Lung, central nervous system, liver, kidneys, skin, and bone marrow.
Exposure/Epidemiology:
Used in ceramics, glass industries, and production of fireworks; for details see under the heading aluminum.
Thresholds: |
TWA |
STEL |
|
mg/m3 |
mg/m3 |
| Germany | 6 | |
| Switzerland | 6 | |
| Great Britain | 10 | 20 |
| Russia | | 4 |
| Sweden | 10 | |
Etiology/Pathophysiology:
The inhaled aluminum silica particles induce a diffuse interstitial lung fibrosis. It is still debatable whether aluminum or the silica particles are the fibrogenic agent. Detailed data about the asthmatic reactions are not known; for details see under the heading aluminum.
Lung Diseases:
Diffuse interstitial fibrosis, asthma, intoxication.
Clinical Presentation:
Patients suffer from nonspecific symptoms as usually seen in silicosis patients; for details see under the heading aluminum.
Radiology:
Chest radiographs usually show finenodular and reticular patterns in all parts of the lung.
Lung Function:
Restrictive changes are the characteristic findings.
Bronchoalveolar Lavage:
The T4/T8 ratio may be altered as well as the concentration of complement.
Pathology:
Gross:
Shrunken lungs with fibrotic bundles and multiple subpleural emphysematous cysts are characteristic; for details see under the heading aluminum.
Histology:
Depending on the stage all morphological alterations seen in diffuse interstitial fibrosis or honeycombing may be present, i.e., acellular collagenous bundles with scattered inflammatory cells, collections of dust-laden macrophages in the distant airways, hyperplasia and atypia of the cells of the alveolar lining, or enlarged empty air spaces; for details see under the heading aluminum.
Prognosis:
Usually poor due to progressive interstitial fibrosis.
Additional Diseases:
Brain:
Alzheimer’s disease; for details see under the heading aluminum.
Liver:
Liver dysfunction in patients undergoing hemodialysis.
Skeleton:
Osteomalacia in patients undergoing hemodialysis.
Skin:
Chronic ulcer.
Kidneys:
Chronic renal failure.
Remarks:
Emery is the common form, which has a content of Fe oxides.
References:
search Pubmed for Corundum
Lewis RJ: Carcinogenically active chemicals. Van Nostrand Reinhold, New York (1991)