Caustic Soda in Soap Making
soap making with caustic soda flake

Caustic Soda Flake for Soap Making

soap making
Soap keeps our world safe. It cleans homes and businesses, offices, and manufacturing plants_versatile, gentle, and effective, it is in many ways the essential product. Without soap, proper sanitation is nearly impossible.
Humans have made basic soaps for millennia — archaeologists have found fragments of soap recipes dating from as early as 2800 BCE. According to one legend, the word “soap” comes from ancient Rome, where animal fat unintentionally mixed with wood ash during religious ceremonies on Mount Sapo. People discovered the resulting paste was an effective cleaning agent, and they called it “sapo” in recognition of its origins.

Sodium hydroxide, also called caustic soda or lye, is a traditional ingredient for soap-making. While potassium hydroxide is more common in liquid soap-making, it is possible to produce liquid soaps using caustic soda. One of the most commonly used chemicals in the soap industry, sodium hydroxide is a strong base with a broad range of potential applications. Sodium hydroxide is a water-soluble compound that comes in pellets, granules, flakes, or powders.

Sodium hydroxide forms through the electrolysis of sodium chloride, and is a powerful alkali. When added to water, sodium hydroxide increases the pH of a substance, which makes it a valuable pH adjuster in acidic formulas.

An inorganic base, sodium hydroxide does not contain any carbon atoms, similar to water. When mixed with water, sodium hydroxide dissociates completely to just hydroxyl and sodium ions. The hydroxyl ions carry a negative charge, and the sodium ions have a positive one. This influx of ions leads to a strong exothermic reaction, which helps hydrolyze fats in the saponification process to form soaps.

Caustic soda

Sodium hydroxide is a reagent, or a substance used in a chemical reaction to produce other substances. Caustic soda causes saponification and is an essential ingredient in soap-making. When flakes or beads of sodium hydroxide get added to a liquid, it forms a lye solution. This solution, when mixed with oils or fats, will lead to a chemical reaction called saponification.

Today, most industrial soap-making takes place through a continuous process, which produces a steady stream of soap instead of small batches.
Manufacturers first split natural fats into fatty acids and glycerin, typically through a tall, vertical steel column called a hydrolyzer that uses high temperatures to break the fat into its two components.

Once separated, the fatty acids get distilled for further purification. Next, the purified fatty acids get mixed with a precisely measured amount of caustic soda. The subsequent saponification creates soap. During this stage, other chemicals may be added to increase shelf life, cleansing power, or marketability. But you can also make liquid soap with caustic soda in small batches. You can find many different recipes for making small-batch liquid soap, but the general process remains the same. 

Four Steps to Make Soap

1. You must have a type of fat — the most commonly used fats derive from plants, such as palm kernel oil, coconut oil, and olive oil. You can use one type of oil or a combination of two or three, for example, 70 percent coconut oil and 30 percent olive oil.

2. Make lye water. Mix the caustic soda with water until it dissolves. The reaction of sodium hydroxide and water is exothermic and will produce heat, so use caution during this stage of the process.

3. Combine the oils with the lye water. Once mixed, allow the soap to rest up to 24 hours.

4. After the soap has set, slowly add heat and water until the soap is smooth and at a proper liquid consistency.

By the end of the saponification process, sodium hydroxide is no longer present in the soap. it has been completely dissociated and used in the chemical reaction. Keep in mind that it is essential to weigh your ingredients instead of measuring them. The amount of lye is based on the weight of the oil, not the fluid ounces. Different oils have different densities. one cup of olive oil will not weigh the same as one cup of coconut oil. To ensure you have the right ratio, weigh your ingredients before mixing.


Caustic soda in leather manufacturing
Caustic soda in leather manufacturing

Caustic soda in leather manufacturing

Caustic soda in Leather Manufacturing: caustic soda as a highly reactive alkali
is widely used in various industries.
Caustic soda has a faster and stronger reactivity than other alkali materials.
The tannery or leather process makes the corrosive skin a stable,
permanent and flexible natural material for many applications.
This natural material is called “leather”, which has many uses.
Leather dressing or tanning has several stages during which the skin turns into

Souse and soaking

Chemicals used in the leather industry
At this stage, the skin will soda from salt.
Cold water is passed through the soda salt skin and the salt dissolves in water.
With this, the skin becomes aqueous.
In this process, some proteins in the skin are removed from the skin with blood
and other water-soluble proteins.
Exit of these proteins increases the quality of the skin.
At this stage, antibacterial agents (often chlorine compounds) are commonly used.
And, substances such as sodium sulfide (S2Na) or sodium
tetra sulfide (4 s2Na) can be used in water.
Until the root of the hair becomes loose.
then, water-soluble proteins are removed from the skin,
the skin returns to its natural state by absorbing water.
And it will be ready for the next steps.


At this stage, lime operations are performed on the skin.
By raising the pH of the blood, the roots of the hair are loose and help
remove excess proteins and fats.
By placing the skin in this environment, the keratin molecules of the hair are
broken down without skin collagen damage.


After the lime scale process, it is necessary to remove all unnecessary skin tissues.
At this stage, using a device called the muscle, meat and other extra tissue
remaining on the skin separated from it And cause the chemicals that
are used in the next steps to uniformly penetrate the skin.

Leather Lining and Curling

After decay, you must remove wool and hair and other proteins from the skin.
To do this, they put it in a solution of lime and add a little sodium sulfide.
It combines hair and hair wrapping.
In addition to sodium sulfide, other compounds such as methylamine,
sodium sulfide and sodium carbonate are also used;
These materials are used to facilitate the process of manipulation.

Remove lime

The remaining lime from the previous step must be completely removed
as it may cause the staining phase to be difficult.
For this purpose, chemicals used in the leather industry such as ammonium
salts, sodium bisulfite,Sulfuric acid.


The skin is eaten in an alkaline solution with ammonium salts,
which increases the effect of enzymes.
And the surface of the skin is smooth and clean.
Meanwhile, the flexibility of the skin also increases.

Fat removal

The skin of some animals is greasier and requires a separate step to remove fat.
At this stage, sodium hydroxide is usually used to convert fat to soap
and to wash it with water.

Leather coloring

For coloring leather, organic colored materials and inorganic colored
materials such as zinc oxide and lead chromite are used.

Classification of chemicals
Classification of chemicals

Classification of chemicals

Classification of chemicals: Dangerous goods are classified and labeled
in many countries according to the United Nations system.
In this system, hazardous goods are categorized according to their hazardous properties in six classes.
These classes include nine distinct classes and a different class of materials.
The risks for each class are marked with special rhomboidal labels.
Some hazardous goods, including classes 8, 4, 1, 2 and 9, have sub-classes.
Which indicates a certain aspect of the dangers of the substance.
In some classes, subsequent categorization includes packaging groups
, which indicates the relative risk of matter inside a class
(PG-III low risk, PG-II medium risk, high-risk PGI)
Therefore, all packages, containers, and tankers carrying hazardous goods should
be labeled appropriately with the appropriate class name.
This label shows the nature of the risk using a color system and special characters,
as well as a hazard class item.

Class 1 Explosive

class 1

Includes substances that can cause explosions or pyrotechnic effects.
Production of explosives is generally limited and is subject to the relevant regulations.
The use of explosives for research needs is subject to obtaining the necessary permissions from the responsible organizations.

Explosives include 6 sub-classes:

Class 1-1 Explosives with a sudden and fearful explosion
Example: TNT Nitroglycerin, Mercury Fulminate

Class 1-2 Explosives with Risk of Throw (but not the danger of a blast of fearsome)
Example: bombs, grenades

Class 1-3 Explosive materials with a high fire hazard
Example: gunpowder, fireworks

Class 1-4 Explosives without fearsome explosion
Example: Fireworks on Toys

Classes 1-5 Explosive explosives with low explosive sensitivity
Depower like Proprietary Example: Explosive

Class 1-6 Explosive materials with very low explosive sensitivity

Class 2 gases

class 2

The hazardous goods of this class include pressure gases, liquid gases or pressure gases.

Gases include 3 sub-classes:

Class 2-1 flammable gases

Class 2-2 Non-flammable and non-toxic gases

Class 2-3 toxic gases

Toxic gases are gases that inhale them to cause death or serious health damage to humans.

Example: chlorine and ammonia.

Class 3 flammable liquids
class 3

For liquids flammable, a mixture of liquids or liquids containing solids is soluble or suspended.

Which can ignite in contact with a source of ignition, such as gasoline, thinners, paints, varnishes and flammable solvents?

It should be noted that in the older segmentation of this class, two sub-scales were divided into two sub-classes: 0-2 and 0-1.

But the new classification for subclass flammable liquids has not been taken into
consideration, but for these materials, the packaging groups (PG I, II, III) have been

PGI grade 3 – Highly flammable liquid
With an initial boiling point less than 08 ° C

Example: Di-ethyl ether, carbon disulfide

Class PG-II -3 Flammable Liquids Extremely high
With an initial boiling point greater than 08 ° C and a flash point less than
10 ° C

Like: gasoline, acetone

Class PIROGI -3 flammable liquid with flash point 10 to 92 ° C

Example: Crown, Turpentine Mineral

This group was called “subclass 2-3” in the previous division

Class 4 flammable solids

class 4

Hazardous materials in this class include materials with spontaneous combustion
potential as well as materials that can cause flammable gases in contact with water.
Also, solids (other than explosives) that immediately burn or cause fire are also classified in this class.

This class contains 3 sub-classes:

Class 4-1 flammable liquid

Materials that are easily ignited and combustible.
Example: Nitrocellulose, phosphorus, matches, and Acid Pic

Class 4-2 cylinders with spontaneous combustion potential
Example: Charcoal, cotton and white phosphorus

Class 4 – Dangerous substances in the wet state
Includes solids that create flammable gases in contact with water.
Example: aluminum phosphide and calcium carbide

Class 5 oxidizing substances

class 5

The oxidizing agent contains 2 sub-classes:

Class 5-1 Oxidizing agents (other than organic peroxides)

Like hydrogen peroxide, calcium hypochlorite (used in pools), ammonium nitrate and nitrates

Class 5-2 Organic peroxides (solid or liquid)

Examples: Methyl Ethyl Ketone Peroxide, Benzoyl Peroxide, Di benzoyl, and Per
Acetic Acid.
Oxidizing substances are not necessarily combustible by themselves but may cause other materials to ignite.
For example, sodium peroxide in the presence of water creates a strongly exothermic reaction,
and the need for mixing with charcoal also causes spontaneous combustion.
Organic peroxides have a structure with bivalent oxygen.

These materials are thermal insecure materials and therefore may spontaneously
decompose, which can sometimes cause explosive reactions or burn quickly,
or be sensitive to impact or friction, or produce dangerous reactions with other materials

Class 6 Toxic and Infectious Substances

class 6


This class includes two sub-classes of toxic substances and infectious substances,
but toxic gases, previously classified in class 3-2, are not included in this class.

Class 6-1: Toxic substances (including liquids and toxic solids)

Toxic substances include substances that cause death or serious injury
and serious harm to humans if swallowed, inhaled or through skin contact.

Example: Sodium Cyanide (NaCN) Cyanides and Arsenic Compounds.

Class 6-2 Infectious agents

Substances are substances that are known to be infectious or possibly
pathogenic (microorganisms include bacteria, viruses, rickettsia, parasites, and fungi).
Vaccines and pathological specimens are examples of this.
The maintenance instructions, how to work and how to dispose of infectious
substances should be in accordance with the health regulations and the
mode of transportation of this group of materials subject to the provisions
of environmental protection

Class 7 radioactive substances

This class contains materials or materials that constantly emit radioactive contaminants.
More precisely, the radioactive substance is a substance with a specific activity greater than 70 KB q / kg.
The activity is specific to activity in a unit mass of a radioactive substance.
There are no sub-classes for this class, but different packing groups are considered.
Example: Radioisotopes and uranium

Class 8 corrosives

class 8
Corrosive materials are solid or liquid substances that can damage the living tissues
and equipment during contact with chemical agents.

In other words, corrosive substances are substances that, by chemical action,
cause severe damage to living tissues, equipment, and other materials.

Examples: Hydrofluoric Acid,


, and Clay Pools.

Class 9 Miscellaneous materials

class 9
This class shows the risk of miscellaneous materials that are not particularly severe
and are not classified in other classes.

Such as intense magnetic materials, aerosols, ammonium nitrate fertilizers,
and polyester granules.

Dangerous goods labels

This label represents various classes of hazardous goods and is used when
shipping these goods.

Why caustic soda?
Why caustic soda?

Why caustic soda?

Why caustic soda? Sodium hydroxide as a highly reactive alkali is widely used in various industries.

Caustic soda has a faster and stronger reactivity than other alkali materials.

This material does not produce adverse effects such as carbon dioxide or other carbonates during chemical processes.

Caustic soda can be used for pulp and paper industry, aluminum production,

Ink-removing waste paper, water purification and disinfectants.

Caustic soda is the primary substance in the production of many chemicals.

This substance is used as an intermediate and reactive process in which
many materials are made up of solvents, plastics, synthetic fibers,
bleaching agents, adhesives, coatings, inks, paints,
herbicides and pharmaceuticals such as aspirin.

Caustic soda is also used for the soap and construction of detergents, oil and gas industries,

The ceramic industry is used to neutralize acidic wastewater and to clean and
remove acidic compounds from exhaust gases.

so, this chemical is one of the most used chemicals in the industry.

Usages of sodium hydroxide

Chemical production:

In the chemical industry, about 40% of the produced caustic soda is used as a
base material for the production of many chemicals.

Detergent and disinfectant products:

Caustic soda is used for the production of soap and detergents with various
household and industrial applications.
Chlorine bleaching solutions (bleaching agents containing chlorine such as sodium
hypochlorite) are obtained from the combination of chlorine and caustic soda.
Tubes that contain caustic soda,
By converting fats and oil materials that have the potential for blockage of pipes
and water and sewage routes,
Water soluble materials prevent blockage of the pipes.

Medical and Pharmaceutical:

Caustic soda in the production of many pharmaceutical and medical substances
from simple painkillers, such as aspirin, to anticoagulants that can prevent blood coagulation and
It is used in steroidal anti-arrhythmic drugs.

pulp and paper production:

Sulfate and sulfite pulp produced by purification of lignin compounds using
multiple units extracted by liquid caustic soda are purified.
Also, in some factories that use the craft process to produce paper,
Liquid sodium hydroxide is used.
In addition to the usages of caustic soda, in the paper industry,
this chemical isThe Initial removal of ink from recycled paper.

cellophane and silk:

The production of fibers using the viscose process requires two main steps needs caustic soda.
Cellulose is used to enhance the strength and shine, resulting in the production
of alkaline cellulose by the liquor of treated liquid,
The resulting cellulose is then dissolved in the diluted liquid extract to produce
viscose material used to extrude silk fibers and cellophane films.

Aluminum extraction:

The use of caustic soda in the aluminum industry is used to dissolve bauxite ore,
which is the primary material for the production of aluminum,
and the deposition of aluminum?
Caustic soda is also used for chemical brushes of aluminum products.

Soap making:

The caustic soda converts fats into water-soluble soaps.
the cloth:
In this industry, caustic soda is used to clean, whiten and enhance the shine
and toughness of the cloth.

Oil production and refining industry:

Caustic Soda as a carbon dioxide absorber in lightweight cuts
As sulfide adsorbent, it is used to purify various oil cuts.
Also, caustic soda along with chlorine for the hypochlorite
sweetening process that is a process for
The removal of various sulfur compounds is applicable.

Sodium carbonate substitute (soda ash):

Caustic soda is used as an alternative to its hydrate in many applications in the glass
paper, pulp, phosphate and silicate industries.

Food Production:

Sodium hydroxide is used in the production and processing of several nutrients.
Such as the use of caustic soda in the processing of olive or in the process of producing woody salty to create brittle.
The fruit is used to separate the peel of potatoes, tomatoes and other fruits for canning.
Also, caustic soda is used to prevent the growth of bacteria and mildew in certain foods and to prevent their corrosion.

Water and Sewage Treatment:

In water and wastewater treatment plants, water utilization is used to control
the acidity of water and help remove heavy metals from water.
Also, the caustic soda is in the production of sodium hypochlorite (bleach),
which is an antiseptic.


The use of caustic soda is used in the production of fuel cells.
In the manufacture of epoxy resins, which are used in wind turbines,
Caustic soda is used.

Nonrenewable fuels:

Caustic soda is used to adjust the pH and produce sodium methyl’s in the
bio-ethanol and biodiesel production process.