CAUSTIC SODATransforming saltinto various productsfor our daily lives.

CA

US

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An importantchlorineco-product

The transformation of salt and water into caustic soda and chlorine

The chlor-alkali production chain begins with electrolysis, by passing an electrical current through a solution containing sodium chloride (salt) and water, using one of the three most common processes in its industrial manufacturing: mercury cells, diaphragm cells or membrane cells. Electrolysis is the process whereby salt and water molecules are broken and subsequently regrouped into caustic soda, chlorine and hydrogen molecules. The production results in a fixed ratio of 1.12 tons of caustic soda per ton of chlorine. Hydrogen, which is also a by-product of the electrolysis, is recovered and then used as fuel or raw material for the production of hydrochloric acid. Other products in this industry are sodium carbonate (soda ash), potassium hydroxide (caustic potash), hydrochloric acid and sodium hypochlorite.

Caustic soda is an essential reagent for the production of various organic chemical products. Among the main applications is the bleaching of pulp and paper, besides being widely used in the chemical and petrochemical industry, metallurgy (alumina production for the aluminum industry), soaps and detergents, textile and food industries. Of natural origin, it plays an important role in pollution prevention and treatment of wastewater, enabling many industrial processes (for further details see the products derived from caustic soda inside this booklet).

In 2015, the worldwide production capacity of caustic soda stands at around 92 million metric tons.

Caustic soda is highly valued for its neutralizing power and also because it helps to control and remedy acidic pollution of the environment. Therefore, it is used in various processes to control acidity, neutralize acid wastes and washing gases. As it is an alkali compound, caustic soda is a chemical opposite to acids and can therefore neutralize them. The neutralization reaction produces water and salt. Gas washers are devices used for air pollution control designed to use the alkaline properties of caustic soda. Such systems neutralize the acid gas emissions from chimneys, thereby helping to make the environment cleaner and pollution free. Moreover, metal plating facilities generate waste containing dissolved heavy metal concentrations that must be removed before the effluents are discharged into municipal sewers and surrounding water bodies. Normally this can be achieved by adding an alkaline chemical product like caustic soda to the effluents. The insoluble metal hydroxides formed by the reaction between caustic soda and metals of effluents are physically removed as part of the pre-treatment of effluents.

Caustic soda can also be used to neutralize acid drainage from mines. During mining opera-tions, when air and water come into contact with freshly extracted minerals containing sulfur, these rapidly oxidize and release a certain amount of acidity, metals and other chemical components that are harmful to the environment. Acid mine drainage is a major environmen-tal hazard. Caustic soda is particularly effective in neutralizing low flows of acid drainage from mines in remote locations, as well as treating flows that have a high manganese content.

Caustic soda plays an important role in the manufacture of soap powders, soap bars and detergents, in addition to being used in the production of industrial soaps and special soaps. Developing countries have a significant demand for caustic soda, because in some of these countries, bar soap is used exclusively for washing fabrics and for personal hygiene. The special soaps include soaps for cleaning ovens and equipment for food preparation, more potent detergents for dishwashers, floor cleaning, metal cleaning, paint removers, liquid soaps and shampoos.

Caustic soda is used in the production of cotton fabrics to strengthen the fibers and better absorb the dye. Estimates indicate that around 90% of the cotton is treated with caustic soda. Caustic soda also has a number of other applications in the food industry, for example, in refining animal and vegetable oil, to remove fatty acids and to peel vegetables and fruit, as well as in the pharmaceutical industry where sodium phenolate is used in antiseptics and to produce aspirin (acetylsalicylic acid). Large quantities of caustic soda are also demanded by the pulp industry to manufacture paper and in the alumina manufacturing process to produce primary aluminum. Additionally, significant amounts of caustic are used in treating municipal and industrial waste water.

Helping tocontrol pollution

Help in personal hygiene

Various andnumerous applications

Caustic Soda Applications

Caustic soda is the main by-productin chlorine production.

5% 12%

14%

14%

15%

17%

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Water treatment

Inorganic chem. Prods.

Aluminum industry

Paper & Pulp

Soaps, detergents and textiles

Organic chem. Prods

Other

#HereThereIsCausticSoda

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Fabric

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Electro

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Coatin

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Essences (a

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Perfumes

Sodium

chloroacetate

Sodium cyanide

Sodiumformiate

Sodium chlorite Bleaching of fabrics, paper pulp, edible oils, straw productsOxidizing agents for dyes

Sodium-carboxymethylcellulose

Dyes

Vitamins

2.4 Dichlorophenoxy acid - aceticCrop protection chemicals

AdiponitrileHexamethylenediamine

Nylon 66

Nylon 610

Expansion agents

buoyancy agents in sea rescues

Fuel cell

Pharmaceuticals

Metal prints on glass

Polymerization catalyst

Rocket propellants

Elastic fibers for clothing

Food products (especially ice-cre

ams and diet foods)

as a drying agent, thicke

ner, suspending agent and emulsio

n stabilize

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Paper coating, printing, pharmaceutica

l and cosmetic products /

fabrics manufacture (dyes)

Artificial blood vessels / Synthetic grass (sy

nthetic floors) /

Car carpets / Tow / Electric w

ire insulators / fishing lines and nets /

Gears and bearings / Parachutes / Pen tips / Rugs and carpets/

Boat sails / Surgical sutures / Te

nnis racket strings

Toothbrush bristles, hairbrushes, brushes / S

ocks /

Tire strengthening materials / C

lothing (combination of wool

and cotton to increase durability and resistance)

Steel tempering process and thermal treatment agent

Ethylenediaminetetraacetic acid (EDTA)

Blood anticoagulant and to reduce cholesterol /

Liquid soaps / Shampoos

Ore flotation

DyesPharmaceuticals

Black nickel platingDyingPharmaceuticalsRubber treatments

Extraction agent in mining for theproduction of gold and silver

Electroplating agent for copper,zinc, brass and cadmium

Fabric degumm

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Black dyes

Leather preparation

Blueprint copy paper / Ceramics and glasses

Fixer for dyes / Hydrogen peroxide stabilizer

Fireproof fabrics / Tin plating

Zinc d

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Crop p

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chem

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Remov

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Ceram

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Pigmen

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Button battery

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Cosmetic

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Paint pigment

Perfumes

Pharmace

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Polishing components

ABS resins

Car parts

Boats

Registering machines

Home appliances

Bags

Radiator grids

Shoe heals

Shower boxes

Phones

Toys

Nitrile rubbers

Glass manufacturing

Manufacture of additives for oils and greases

Beetroot sugar refining

Steel carbonization agent

Cadmium electroplating

Fertilizers

Paint pigments

Pharmaceuticals

Condiments, seasonings

Anti-mold agent for food

Antiseptic products

Aspirin (acetylsalicylic acid)

Intermediary dyes

Home appliances / Car panels

Cosmetics and packaging

Gardening equipment

Medical equipment / Toys

Electrical enclosures / Cutlery

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Fung

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CatalystsFixer for dyesAgent for leather tanning

ElectroplatingPharmaceuticals

Oxalic acidWallpaper printing

Automotive radiator cleaner, purifying

and intermediary agents for chemical

components, rare earths processing,

Fabrics bleaching, Leather tanning)

Cellulose xanthate

Alkaline cellulose

Wrapping for gifts and packages

Mixed with cotton household products

(curtains, bedspreads, tablecloths)Coated fabricsFelt articles and blanketsNon-woven fabricsClothing

Rayon

Cellophane

Ethylcellulose

AdhesivesVarnishes

(bowling pins, electrical equipment coating)Paints for stampingPharmaceuticalsCoating for pillsLacquers

Coating for foodPaints

Latex paintings

Pharmaceuticals

2-Hydroxypropyl cellulose

2-Hydroxypropyl methylcellulose

Hydroxyethyl celluloseAdhesivesAsphalt emulsions

CementCosmetics

Gelatins and pharmaceutical lotionsFabrics processing

Alum

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Calci

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Zinc s

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Cosm

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Grea

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Phar

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Soap

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Aluminum

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Epoxy

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Purification of gases

Fruit and vegetables peeler

Sodium chemistry

Graphic prints

Galvanization

Oil Refining

Others

Regeneration of ion exchange resins

Food additives

Wood pulp (process with soda)

Wall coating / Pulp bleaching

Sodium stannate

Hydrazine

Sodium Sulphite

Sodium Arsenite / Sodium

Bromite

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Copp

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Mercury OxideAcrylonitril

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Nickel / Beryllium / Barium HydroxideCadmium / Cobalt / Lead Hydroxide

Sodium Molybdate

Monosodium Glutamate

Kraft paper refining (Cellulose)

Sodium Propionate

Sodium Phenolate

Sodium Metasilicate / Sodium Orthosilicate

Sodium Picramate

Polycarbonate

Sodiu

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urana

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ungs

tate /

Fluo

roacet

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Alkaline solutions to wash jars and bottles

Disinfectants / Wastewater treatment

Rubber stabilizers (Latex)

Metal ProcessingFlotation of ores, metal degreaser

pH controlVegetal oils refining / Extraction of gelatin

Rubber regeneration agent

Plastics

Sodium thiocyanate

Electroplating

Oil additives

Sulfur dyes

Synthetic rubber

Aluminum

polychloride (APC)

Aluminum

sulphate

Manufacture of coagulants for treating

water and effluents, catalysts, flexible

polyurethane foams and flam

e

retardant and smoke suppressor in

polymeric m

aterials

Production of glass, glass

fibers, refractory products,

refractory concrete, technical

ceramics, ceramic coatings,

aluminous electrical insulators,

abrasives, white electro-casted

alumina and polishing pastes

Cans, aluminum foil, food

packaging / Windows, doors,

partitions and grids/ Components

in boats, airplanes, cars, bicycles /

kitchen utensils and tools

Aluminum

Aluminum Oxide

(Alumina)

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