This document summarizes information about magnesium extraction processes. It discusses producing magnesium from seawater using the Dow process which involves precipitating magnesium hydroxide and electrolysis. The Magnetherm and Pidgeon processes for extracting magnesium from oxide sources like magnesite are also outlined. These involve high-temperature reduction with silicon or aluminum. The document concludes with applications of magnesium and production in India.

1. YSREC OF YVU
(MMT)

2. NON FERROUS EXTRACTIVE METALLURGY
◦ PRESENTED BY:
◦ 1012101908-S.Haresh 1012107912-G.Manohar
◦ 1012107909-K.Hemanth 1012107913-G.Naveen naik
◦ 1012107910-G.Jayannth 1012107914-J.Padmaja
◦ 1012107911-S.Lokesh 1012107915-P.Pavan

3. MAGNESIUM EXTRACTION
Contents:
◦ Sources of Mg
◦ Production of Mg from sea water
◦ Electrowinning of magenesium
◦ Production of Mg from oxide sources
1. Magnatherm process
2. Pidgeon process
◦ Applications of Mg
◦ Production of Mg in india

4. Properties of Mg:

5. Details about Mg:
◦ Atomic Number: 12
◦ Atomic Weight: 24 amu
◦ Density: 1.738 gm/cm3
◦ Melting Point: 650 C
◦ Boiling Point:1107 C

6. Sources of Magnesium:
Magnesium:
Magnesite:Mgco3
Dolomite:MgCO3.CaCO3
Epsom salt:MgSO4.7H2O
Kiserite:MgSO4.H2O
Carnalite:KCl.MgCl2.6H2O

7. Production of Mg from sea
water:(DOW’S PROCESS)
◦ The process of magnesium recovery from Sea water was developed by the Dow Chemical
Company (U.S.A)and this process is known as Dow′s process.
◦ The Mg2+cation is the second most abundant cation in sea water. To extract the magnesium,
calcium carbonate is added to sea water to form magnesium carbonate precipitate.
◦ MgCl2+CaCO3→MgCO3+CaCl2
◦ Magnesium carbonate is in soluble in water so it can be filtered out ,and reacted with
hydrochloric acid to obtain concentrated magnesium chloride.
◦ MgCO3+2HCl→ MgCl2+CO2+H2O
◦ This magnesium chloride when undergone through electrolysis process produces .Calcium
Hydroxide is also used to collect magnesium as insoluble hydroxide from the sea water
◦ MgCl2+Ca(OH)2 → Mg(OH)2+ CaCl2
◦ MgSO4+Ca(OH)2 → Mg(OH)2+CaSO4

8. Process:

9. Process:(ELECTRO WINNING)
◦ The sea water is taken into tanks and lime is mixed. The suspension is distributed to
thickeners, in which the hydroxide settles.
◦ The overflow is pumped back into the sea.The milk of magnesia under flow is
collected by the slurry pumps and delivered to filter tanks.
◦ Subsequently, magnesium hydroxide is mixed with 10% hydro-chloric acid, which
converts it to a weak solution of the chloride.
◦ When hydro-chloric acid is added to the magnesium hydroxide, magnesium chloride
is formed.
◦ Mg(OH)2 + 2HCl → MgCl2 + 2H2O

11. ◦ The magnesium chloride thus obtained is subsequently subjected to electrolysis to
get magnesium and chlorine gas.
◦ During electrolysis magnesium chloride decomposes and the magnesium in liquid
form floats to the surface of the bath, from where it is collected at frequent time
intervals.
◦ MgCl2 (l) → Mg (l) + Cl2 (g)

12. MAGNATHERM PROCESS
◦ The magnetherm process was developed and implemented as an improvement of the
solid state silicothermic magnesium reduction process. This process was used
commercially for over 35 years. The reduction plant operation and equipment are
described as they existed at the time of the industry wide curtailment.
◦ This technique, utilized in the Magnetherm process, has the advantage that the liquid
slag can be heated directly by electric current through a water-cooled copper
electrode. The reduction reaction occurs at 1,600 °C and 400–670 pascals pressure.
Vaporized magnesium is condensed in a separate system attached to the reactor,
and…

14. Process:
The process is operated at 1500 °C under
25 mmHg. Impurities such as zinc and
manganese are transferred into the
magnesium product because of the high
operating temperature. The purity of the
product by the process is about 99.8% and
low compared to that produced by the
Pidgeon process. In the magnetherm process,
aluminum is not only used as a reductant but
also as a slagging agent for removing slag
out of the furnace.

15. Pidgeon process:(Introduction)
◦ 1.This process is developed by Pidgeon in the early 1940s.
◦ 2.It is one of the methods of magnesium metal production, via a silico-thermic
reduction.
◦ The basic chemical equations of this process are
◦ Si(s) + MgO(s) ↔ SiO2(s) + Mg (g) (high temperature, distillation boiling zone) Mg (g)
↔ Mg (liq, s) (low temperature, distillation condensing zone)
◦ Silicon and magnesia react to produce silica and magnesium.
◦ The most commonly used and cheapest form of silicon is as a ferro-silicon alloy.
◦ The atmospheric pressure boiling point of Mg metal is very low, only 1090 °C, and
even lower in vacuum.

16. ◦ The magnesium ore of this reaction is in the form of magnesium oxide which is calcined to remove
both water and carbon dioxide.
◦ (Ca, Mg)CO3 (s) → CaO.MgO(s) + CO2 (g) (dolomite calcining)
◦ 2MgOCaO(c) + FeSi(c) → 2Mg (g) + CaOSiO2(c) + Fe(c)
◦ (Fe, Si)(s) + MgO(s) ↔ Fe(s) + SiO2(s) + Mg (g)
◦ CaO+ SiO2 → CaSiO3

17. Process:
◦ This is a batch process in which finely powdered calcined dolomite and ferrosilicon are
mixed, briquetted, and charged in a stoichiometric ratio of 6:1 in retorts made of
nickel chrome steel alloy.
◦ The retorts, which are 3 m long and have a bore diameter of 275 mm & each retort
yields 70 kg of magnesium per day.
◦ The retorts, heated externally to a reaction temperature of 1200°C, and evacuated to
13.3Pa.
◦ Magnesium vapor condenses at the cooled ends of the retorts.

20. ◦ The hot reaction zone portion of the retort is either gas fired, coal fired, or electrically heated in
a furnace.
◦ The condensing section equipped with removable baffles extends from the furnace and is water-
cooled.
◦ After 8-10 hours, the application of vacuum is stopped, the vacuum seal is broken.
◦ Due to distillation, very high purity magnesium crowns are produced, which are then remelted
and cast into ingots.

21. Applications of Mg:
◦ the Mg metal fall under two categories.
◦ A:)Non structural :
◦ 1. Alloying
◦ 2. De – oxidation & De – sulphurization
◦ 3. Modifying structure of graphite in cast irons
◦ 4. Pyrotechnics and photography
◦ 5. Cathodic protecton

22. ◦ B:)STRUCTURAL:
◦ 1. Magnesium compounds are used mainly as refractory material in furnace linings for
for producing iron, steel, nonferrous metals, glass and cement.
◦ 2. Magnesium oxide and other compounds also are used in agricultural, chemical and
construction industries
◦ 3. Aluminum-magnesium alloys are used mainly for beverage cans, mag wheels,
engine blocks.
◦ 4. Due to low weight, good mechanical and electrical properties, Mg is widely used
for manufacturing of mobile phones, laptop computers, cameras, and other electronic
components.
◦ 5. Magnesium alloys are also used in making metal luggage, ladders, shovels, cameras,
cameras, race cars, power tools and other gardening equipment.

23. Extraction Plants in india:
◦ Extraction plants of Mg in India.
◦ National Metallurgical Laboratory (NML), Jamshedpur with a capacity of 500t/year.
◦ Central Electrochemical Research Institute (CERI), Karaikudi(T.N) with a capacity of
300t/year.