CALCIUM SULFATE HEMIHYDRATE Chemische Eigenschaften,Einsatz,Produktion Methoden
ERSCHEINUNGSBILD
WEISSES KRISTALLINES PULVER ODER STüCKE.
ARBEITSPLATZGRENZWERTE
TLV: (als Gesamtstaub, kein Asbest und <1 % kristallinen Quarz enthaltend) 10 mg/m?(als TWA); (ACGIH 2005).
MAK: (als alveolengängige Fraktion des Aerosol, ohne Fasern) 6 mg/m? (DFG 2005).
INHALATIONSGEFAHREN
Eine belästigende Partikelkonzentration in der Luft kann beim Dispergieren schnell erreicht werden, vor allem als Pulver.
WIRKUNGEN BEI KURZZEITEXPOSITION
WIRKUNGEN BEI KURZZEITEXPOSITION: Reizt möglicherweise mechanisch.
WIRKUNGEN NACH WIEDERHOLTER ODER LANGZEITEXPOSITION
Risiko der Lungenschädigung bei wiederholter oder längerer Exposition gegenüber Staubpartikeln, wenn
LECKAGE
Verschüttetes Material in Behältern sammeln; falls erforderlich durch Anfeuchten Staubentwicklung verhindern. Persönliche Schutzausrüstung: Atemschutzgerät, P1-Filter für inerte Partikel.
R-Sätze Betriebsanweisung:
R49:Kann Krebs erzeugen beim Einatmen.
R42/43:Sensibilisierung durch Einatmen und Hautkontakt möglich.
R51/53:Giftig für Wasserorganismen, kann in Gewässern längerfristig schädliche Wirkungen haben.
S-Sätze Betriebsanweisung:
S53:Exposition vermeiden - vor Gebrauch besondere Anweisungen einholen.
S22:Staub nicht einatmen.
S36/37:Bei der Arbeit geeignete Schutzhandschuhe und Schutzkleidung tragen.
S45:Bei Unfall oder Unwohlsein sofort Arzt zuziehen (wenn möglich, dieses Etikett vorzeigen).
S60:Dieses Produkt und sein Behälter sind als gefährlicher Abfall zu entsorgen.
Beschreibung
Phosphogypsum is a moist, fine powder with a free water content of ca. 20 – 30 %
and considerable amounts of impurities, the exact impurities and their amounts depending on
the rock and the specific process. The radioactive substances present in small amounts in sedimentary phosphate rock are partly transferred to
the phosphogypsum as 226Ra, leading to slightly
increased radioactivity of such gypsums.
About 1.7 t of gypsum is obtained per tonne of
raw phosphate, corresponding to 5 t of gypsum
per tonne of phosphorus pentoxide produced.
Verwenden
Anhydrous: insoluble anhydrite is used in cement formulations and as a paper filler. Soluble anhydride, because of its strong tendency to absorb moisture, is useful as a drying agent for solids, organic liquids and gases; the desiccant used in laboratory and industry is known under the name Drierite. This material can be regenerated repeatedly and reused without noticeable decrease in its desiccating efficiency. The hemihydrate is used for wall plasters; wallboard; tiles and blocks for the building industry; moldings; statuary; in the paper industry. The dihydrate is used in the manufacture of portland cement; in soil treatment to neutralize alkali carbonates and to prevent loss of volatile and dissolved nitrogenous compounds by volatilization and leaching; for the manufacture of plaster of Paris, artificial marble; as a white pigment, filler or glaze in paints, enamels, pharmaceuticals, paper, insecticide dusts, yeast manufacture, water treatment, polishing powders; in the manufacture of sulfuric acid, CaC2, (NH4)2SO4, porous polymers. Pharmaceutic aid (in plaster casts).
Definition
A powdered mixture of calcium
silicates and aluminates, which is made by
heating limestone (CaCO3) with clay, and
grinding the result. When mixed with
water, reactions occur with the water
(hence the name hydraulic cement) and a
hard solid aluminosilicate is formed.
Allgemeine Beschreibung
White or nearly white, odorless, crystalline solid.
Reaktivität anzeigen
CALCIUM SULFATE HEMIHYDRATE is generally of low reactivity. Can serve as an oxidizing agent under forcing conditions. Incompatible with aluminum (at high temperatures) and diazomethane.
Landwirtschaftliche Anwendung
Calcium sulphate (CaSO
4) is a white solid that occurs
naturally as a mineral anhydrite. It is found more
commonly as dihydrate, called gypsum (CaSO
4·2H
2O).
When heated, gypsum loses water at 128°C to give a
hemihydrate (2CaSO
4·H
2O), also known as plaster of
Paris.
Calcium sulphate is sparingly soluble in water and
makes water permanently hard. CaSO
4 is used in the
manufacture of certain paints, ceramics and paper. Its
naturally occurring form is used in sulphuric acid
manufacture.
Gypsum is the cheapest and the most useful material
in reclamation of sodic soils.Calcium, solubilized from
gypsum, replaces sodium, leaving behind the watersoluble
sodium sulphate, which is leached out as a result
of the following reactions in the soil:
Since both reactions are reversible, adequate leaching
arrangements have to be made to remove sodium
sulphate.
The application of about 40 t/ha of gypsum in Nevada
(USA) was seen to increase water infiltration and the
depth of water penetration substantially. These two
measures increased hay yield up to 2.3 t/ha per year.
Gypsum requirement (GR) is the amount of gypsum
necessary to be added to reclaim soil and is calculated
using the formula:
The gypsum requirement is equivalent to (Na
x)×4.50
metric tons of gypsum per hectare for a 30 cm fixed
depth, where Na, is the milliequivalent of exchangeable
sodium to be replaced by calcium from the added gypsum.
CALCIUM SULFATE HEMIHYDRATE Upstream-Materialien And Downstream Produkte
Upstream-Materialien
Downstream Produkte
