Glauber Salt Overview

Historically, Glauber salt is named after Johann Rudolf Glauber, german chemist, who discovered it in the 17th century in Hungarian spring Water, and known variously as Glauber’s salt and ‘sal mirabilis’ (sodium sulfate). Glauber was born in Karlstadt, Franconia, and was self-educated. After many years of travelling in Europe, he settled in Amsterdam 1655 and built a chemical laboratory there.

He made his living selling patent medicines and used the salt to treat almost any complaint. The white or colorless crystals of Glauber Salt were used as a laxative until more sophisticated alternatives came about in 1900′s. In the eighteenth century, Glauber’s salt began to be used as a raw material for the production of soda ash, by reaction with potash. In the nineteenth century the Leblanc process became the principal method of soda production, and one of the world’s major chemical processes, using synthetic sodium sulfate as a key intermediate.

Sodium sulfate, chemical compound, Na2SO4. It is a white, orthorhombic crystalline compound at ordinary temperatures; above 100°C it assumes a monoclinic structure, and above about 250°C it assumes a hexagonal structure. Sodium sulfateis soluble in cold water and very soluble in hot water. With an annual production of 6 million tonnes, it is one of the world’s major commodity chemicals. It forms two hydrates; the decahydrate is glauber salt. Anhydrous sodium sulfate is found in nature as the mineral thenardite. In its natural form, sodium sulfate is found in two minerals, mirabilite (Glauber salt) and thernadite. Its occurrence is widespread and it is commonly found in mineral water such as sea water atmospheric precipitation and saline lakes. Essentially all commercial deposits of sodium sulfate resulted from the accumulation and evaporation of surface and ground water in basins with interior drainage. These basins, or playas, are found in arid or semiarid regions.

The major commercial source of sodium sulfate is salt cake, a byproduct of the production of hydrochloric acid from sodium chloride (common salt) by treatment with sulfuric acid. It is obtained (with other chemicals) by evaporation of natural brines. It is also obtained as a byproduct of viscose rayon manufacture and in several other, less important ways. The principal use of sodium sulfate is in processing wood pulp for making kraft paper. It is also used in glass manufacture, textile dyeing, and synthetic detergents

Sodium sulfate is produced from naturally occurring brines or crystalline mineral sources and as a byproduct from various chemical processes. It is used to make many consumer products used by virtually everyone, such as powdered laundry detergents, brown paper bags, textiles and glass. The estimated distribution of sodium sulfate by end use in 1994 was detergents (40%), paper and pulp (20%), textiles (19%), carpets fresheners and glass (5% each), and miscellaneous (11%). The largest use of sodium sulfate is as an inert filter with a brilliant whiteness that provides bulk in powdered laundry detergents. This use is waning as domestic consumers are increasingly switching to compact or liquid detergents that do not include sodium sulfate.

The textile industry is another domestic market that consumes sodium sulfate. In the dyeing process, sodium sulfate is blended with dyes to standardize the concentration of the dyes. Sodium sulfate helps in “levelling”, reducing negative charges on fibres so that dyes can penetrate evenly. Unlike the alternative sodium chloride, it does not corrode the stainless steel vessels used in dyeing. This application in Japan and USA consumed in 2006 approx. 100,000 tonnes.

Another formerly major use for sodium sulfate, notably in the USA and Canada, is in the Kraft process for the manufacture of wood pulp. Organics present in the “black liquor” from this process are burnt to produce heat, needed to drive the reduction of sodium sulfate to sodium sulfide.

However, this process is being replaced by newer processes; use of sodium sulfate in the USA and Canadian pulp industry declined from 1.4 Mt/a in 1970 to only approx. 150,000 tonnes in 2006.

The glass industry provides another significant application for sodium sulfate, as second largest application in Europe. Sodium sulfate is used as a fining agent, to help remove small air bubbles from molten glass. It fluxes the glass, and prevents scum formation of the glass melt during refining. The glass industry consumes stably from 1970 to 2006 in Europe at 110,000 tonnes.

The miscellaneous uses of sodium sulfate include ceramics, chemicals (potassium sulfate, sodium hyposulfite, sodium sulfide, sodium silicate and sodium aluminum sulfate), feed supplements, printing inks, sulfonated oils, veterinary medicines and viscose sponges. In 1995 growth in total world sodium sulfate demand was forecast at up to 8%pa, but reduced to around 3%pa by 1996. The recent economic difficulties in Asia and Russia have meant that forecasts have again had to be reviewed downwards.
In the laboratory, anhydrous sodium sulfate is widely used as an inert drying agent, for removing traces of water from organic solutions. It is more efficient, but slower-acting, than the similar agent magnesium sulfate. Sodium sulfate is added to the solution until the crystals no longer clump together. Glauber’s salt, the decahydrate, was historically used as a laxative.

In 1953, sodium sulfate was proposed for heat storage in passive solar heating systems. This takes advantage of its unusual solubility properties, and the high heat of crystallisation (78.2 kJ/mol). Sodium sulfate can be used in swimming pools, hot tubs and spa bathing waters to reduce the alkalinity of the waters. It is less irritating to the eyes and skin than other treatments. Other uses for sodium sulfate include frosting windows, in carpet fresheners, starch manufacture, and as an additive to cattle feed.

Lately, sodium sulfate has been found effective in dissolving very finely electroplated micron gold that is found in gold electroplated hardware on electronic products such as pins, and other connectors and switches. It is safer and cheaper than other reagents used for gold recovery, with little concern for adverse reactions or health effects.

Application
In the Kraft pulp manufacturing process, Sodium Sulphate is used to make up sodium and sulphur levels during the recovery of the cooking liquor. SQM is the main producer in South America. This product is obtained as a by-product of Sodium Nitrate. Production capacity is 75,000 metric tons per year.

Main uses: Detergents, pulp and paper, glass and textiles. In the Kraft pulp manufacturing process, Sodium Sulphate is used to make up sodium and sulphur levels during the recovery of the cooking liquor.

ITEMS

INDEX

REMARK

National
Standard

Typical Analysis

Y

Tong Qing

Yin
Zhu

Na2SO4

99.0

99.2

99.2

99.2

The figures of the typical analysis are only for the sample tested.

Water insolubles

0.05

0.05

0.01

0.03

Mg+

0.15

0.10

0.03

0.08

CL

0.35

0.09

0.10

0.15

Fe

0.002

0.0015

0.001

0.0015

Moisture

0.20

0.05

0.07

0.05

Whiteness

80

84

88

84.2

PH Value (1% solution)

7.5

10.5

7.9

Size (Passing 100mesh)

50%

60%

80%

Bulk Density

1.25

1.39

1.49

Synonyms : Disodium sulfate; sodium sulfate anhydrous; sulfuric acid, disodium salt; sodium sulfate
CAS No. : 7757-82-6
Molecular Weight : 142.04
Chemical Formula : Na2 SO4

 
 

Hazards Identification
Emergency Overview
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As part of good industrial and personal hygiene and safety procedure, avoid all unnecessary exposure to the chemical substance and ensure prompt removal from skin, eyes and clothing.

Potential Health Effects
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Inhalation : Not expected to be a health hazard.
Ingestion : Mildly toxic by ingestion. Slowly absorbed from the alimentary tract. Because of osmotic activity, it will draw water into the lumen of the bowel and may cause purging, fluid loss, blood in stools, fall of blood pressure, and high sodium levels in the blood.
Skin Contact : No adverse effects expected.
Eye Contact : No adverse effects expected but dust may cause mechanical irritation.
Chronic Exposure : No information found.
Aggravation of Pre-existing Conditions : No information found.

First Aid Measures
Inhalation : Not expected to require first aid measures.
Ingestion Give several glasses of water to drink to dilute. If large amounts were swallowed, get medical advice.
Skin Contact : Wash exposed area with soap and water. Get medical advice if irritation develops.
Eye Contact : Wash thoroughly with running water. Get medical advice if irritation develops.

Fire Fighting Measures
Fire : Not considered to be a fire hazard.
Explosion : Not considered to be an explosion hazard, but violent explosions occur when potassium sulfate and sodium sulfate are melted with aluminum.
Fire Extinguishing Media : Use any means suitable for extinguishing surrounding fire.
Special Information : Use protective clothing and breathing equipment appropriate for the surrounding fire.

Accidental Release Measures
Ventilate area of leak or spill. Wear appropriate personal protective equipment as specified in Section 8. Spills: Sweep up and containerize for reclamation or disposal. Vacuuming or wet sweeping may be used to avoid dust dispersal.

Exposure Controls/Personal Protection
Airborne Exposure Limits : None established.
Ventilation System : In general, dilution ventilation is a satisfactory health hazard control for this substance. However, if conditions of use create discomfort to the worker, a local exhaust system should be considered.
Personal Respirators (NIOSH Approved) : For conditions of use where exposure to the dust or mist is apparent, a half-face dust/mist respirator may be worn. For emergencies or instances where the exposure levels are not known, use a full-face positive-pressure, air-supplied respirator. WARNING: Air-purifying respirators do not protect workers in oxygen-deficient atmospheres.
Skin Protection : Wear protective gloves and clean body-covering clothing.
Eye Protection : Use chemical safety goggles. Maintain eye wash fountain and quick-drench facilities in work area.

Physical and Chemical Properties
Appearance : Fine white crystalline granules.
Odor : Odorless.
Solubility : Soluble in approx. 3.6 parts water, 1 in 2 parts maximum @ 33C (91F).
Density : 2.68
pH : No information found.
% Volatiles by volume @ 21C (70F) : 0
Boiling Point : No information found.
Melting Point : 844C (1551F)
Vapor Density (Air=1) : No information found.
Vapor Pressure (mm Hg) : No information found.
Evaporation Rate (BuAc=1) ; No information found.

Stability and Reactivity
Stability : Stable in tightly closed containers under normal conditions of storage.
Hazardous Decomposition Products : Oxides of sulfur and sodium may form when heated to decomposition.
Hazardous Polymerization : Will not occur.
Incompatibilities : In combination with sodium sulfate, aluminum and magnesium will explode @ 800C (1472F); strong mineral acids and bases.
Conditions to Avoid : Air, moisture, and incompatibles.

Toxicological Information
No LD50/LC50 information found relating to normal routes of occupational exposure. Investigated as a tumorigen, mutagen, reproductive effector.

Ecological Information
Environmental Fate : When released into the soil, this material is expected to leach into groundwater. This material is not expected to significantly bioaccumulate.
Environmental Toxicity : This material is not expected to be toxic to aquatic life. The LC50/96-hour values for fish are over 100 mg/l. The EC50/48-hour values for daphnia are over 100 mg/l.

Disposal Considerations
Whatever cannot be saved for recovery or recycling should be managed in an appropriate and approved waste disposal facility. Processing, use or contamination of this product may change the waste management options. State and local disposal regulations may differ from federal disposal regulations. Dispose of container and unused contents in accordance with federal, state and local requirements.

Transport Information
Not regulated.
Other Information
NFPA Ratings : Health: 1 Flammability: 0 Reactivity: 0
Label Precautions : None.
Label First Aid : Not applicable.
Product Use : Laboratory Reagent.