Industrial production of caustic soda
Sodium Hydroxide is a solid and white substance with a melting point of 1388 ° C and
a density of 13.2.
This material usually reaches 98% or 99% purity for various uses Sodium hydroxide is
presented in four ways in terms of its appearance:
Caustic soda liquid
Sodium hydroxide liquid is Produced by Using the Hydrolysis Process of a Salt Solution,
in Petrochemicals and Liquid caustic soda production Units then will be transported by
special thanks to caustic soda flakes production units.
Caustic soda flakes
Caustic soda flakes are usually in white color and odorless material and are available at the flake.
Caustic soda pearls:
Caustic soda pearls are solid, white and similar to small snowball bullets,
which are used in more precision and finer production?
It is commonly used in pharmaceutical and textile industries with more sensitive applications
Sodium Hydroxide Powder:
This caustic soda or sodium hydroxide, have fairly small grains.
The process of sodium hydroxide production
More than 95% of the chlorine production capacity and approximately 100% of sodium hydroxide
production capacity is based on the hydrolysis of brine Dissolution.
In this process, the sodium chloride solution is decomposed electro less to chlorine
(gas chlorine) and sodium hydroxide and hydrogen.
If instead of using salt water (sodium chloride),
a calcium chloride solution or potassium chloride as the raw material is used,
The reaction product will contain potassium or calcium instead of sodium.
There are also processes where hydrogen converts liquid chloride into hydrogen
or sodium melted chloride to chlorine and metallic sodium.
In producing liquid sodium hydroxide, using sodium chloride as the raw material,
about 1126 kg of sodium hydroxide and 28 kg of hydrogen are produced per 1000 kg of chlorine.
A large amount of hydrogen produced in this process is used to produce ammonia,
hydrochloric acid, and hydrogenation of organic compounds.
Sodium hydroxide production method
Three methods for producing caustic soda:
Producing liquid sodium hydroxide with diaphragm method:
Using the diaphragm method, chlorine, sodium hydroxide (Noah),
and hydrogen is produced simultaneously.
In this process, the two reactor sections are separated by a
permeable diaphragm plate, often made of asbestos.
In the diaphragm reactor, saturated brine enters the anode portion of the cell,
where the chlorine gas is released, and then It flows to the Cathode section.
The role of the diaphragm in this method is to isolate the salt solution from
the liquid sodium hydroxide in the cathode,
where the hydrogen gas is released there.
The product of the process is a dilute solution of Brine and liquid sodium hydroxide.
In this solution, the liquid Density should reach 50% and the salt should be removed.
Sodium hydroxide is spilled over into nickel trays for Condensation.
And is heated at 1400 ° C to condensation from 50% to 98%.
So, about 3 tons of water evaporates per ton of liquid sodium hydroxide
Produce liquid sodium hydroxide with membrane method:
The most common method of sodium hydroxide production is hydrolysis of salt water
in a membrane cell.The difference in this method with the diaphragm method is that
around each of the electrodes in the solution,
surrounded by a diaphragm surrounded by a membrane.
The saturated salt water enters the first reactor chamber
(where chlorine gas is released)It turns out.
Chloride ions are oxidized by the anode and converted to chlorine gas
by losing electrons. In the cathode, the positive ions of hydrogen,
which are obtained by the decomposition of water molecules,
The electric current is restored to the hydrogen gas and the hydroxide
ions released into the solution are released.The ion penetrating membrane in
the middle of the cell only allows for positive ions of sodium to cross into the second part of the cell
While chloride ions remain in the anode section.
In the cathode, hydroxide ions react with sodium ions to produce sodium hydroxide.
The Obtained sodium hydroxide has a significantly lower sodium chloride (salt)
As a result, it has a higher purity and higher quality than diaphragm production
And there is no need for a desalination process.
Produce liquid sodium hydroxide with mercury method:
In this method known as the Kestner-Kellner Process, the salt water saturation
the solution is placed above a thin layer of mercury.
In this process, mercury plays a role as a cathode and interacts with the sodium
formed in the solution, and a mixture of sodium and mercury (amalgam) is obtained.
Sodium-mercury amalgam is continuously released from the reactor and reacted with water,
which leads to the decomposition of this mixture with sodium hydroxide, hydrogen, and mercury.
The mercury is recovered from the mercury process and the chlorine formed in the anode is released
into the gas from the reactor.
Production of caustic soda flakes
Caustic soda is produced by utilizing the liquid caustic soda of petrochemicals during the process
of thickening and evaporation.
The process of producing caustic soda flakes is such that at first sodium hydroxide 50% liquid
is transmitted by special tanks to caustic soda flakes manufacturing companies.
And then, the liquid caustic soda during the process of production in the condensing lines,
while evaporating the water in it, turns into a solid caustic soda of 98-99%.