1. Government Engineering College Bhuj

2. Topic : - Manufacturing of CAUSTIC SODA by mercury cell process. Guided By : Prof. J.D. Rathod Sir. Prof. Z.Z. Painter Sir.

3. Report – 1 Report - 2  Raw Material Raw Material  Reactions Reactions  Flow sheet Flow sheet  Process Description Process Description  Uses Uses  Major Engineering Problems Major Engineering Problems  Material Safety & Data Sheet Material Safety & Data Sheet  Composition Composition  Properties Properties  Production Cost Production Cost  International Price International Price  Producer & Location Producer & Location  Import / Export Import / Export  Production Capacity Production Capacity  References References

4. 1. Raw Material :  The principal raw material is a purified solution of 10-15% NaCl or solid salt depending of the type of electrolysis cell used. Minor quantities of Na ₂ CO ₃ and NaOH for salt purification, and H ₂ SO ₄ for Cl ₂ drying are required.

5. 2. Reactions : NaCl + H ₂ O NaOH + ½ H ₂ + ½ Cl ₂

7. 4.Process Description :  A combination of the diaphragm cell and mercury cell process. ( Flow Sheet Description )  Brine solution flows through pipelines to a storage reservoir and then through a brine treatment system. Caustic soda, soda ash, and/or barium carbonate removes calcium, magnesium and iron salts which would clog up diaphragms.  The purified, saturated brine (25-28% NaCl ) is heated and electrolyzed in a diaphragm cell. The cell, operating at 45- 55% decomposition efficiency, discharges a 10-12% solution of caustic soda with about an equal concentration of NaCl.

8.  Multiple effect evaporation concentrates the cell liquor to 50% NaOH solution. The precipitated salt is separated, centrifuged, washed, and then slurried with treated brine. Salt separator overflow is 50% caustic soda product containing 2% NaCl and 0.1-0.5% NaClO on dry basis. This commercial caustic grade can be evaporated to produce saturated 73% NaOH liquor or fused to flake, granular or stick caustic. Purified grade can be produced by a combination treatment of CaCO ₃ to remove colloidal Fe and liquid NH ₃ counter-current extraction to take out chloride and chlorate impurities.

9. 5. Uses :  Sodium hydroxide is used in the manufacture of sodium salts.  In the paper industry, sodium hydroxide solution is used for cooking wood (removal of lignin).  In the aluminum industry, sodium hydroxide is used mainly for the treatment of bauxite.  Dilute sodium hydroxide for water purification and wastewater treatment.  In the food industry, sodium hydroxide is used for degreasing, cleaning, and for peeling potatoes.

10. 6. Major engineering problems :  The convesion cost of exiting mercury cells and diaphragm cells has become prohibitive. This is due to high cost of capital equipement, high technology transfer fees, compounded by an import duty of 35 percent on capital equipment. Corrosion :  Handling wet chlorine requires stoneware, plastic, glass, or rubber-lined equipment. After drying H ₂ SO ₄ it can be handled in mild steel or iron.  The remainder of the plant can be constructed of cast iron, steel and wood.

11. Report - 2  Chemical Name : Sodium Hydroxide  Trade Name : Caustic Soda  Synonyms : Liquid Caustic Soda, Caustic, Soda Lye, Lye Solution PRODUCT IDENTIFICATION :-

12. COMPOSITION / INGREDIENTS :-  Sodium Hydroxide, % : 48 – 52 % by weight  Chemical Formula : NaOH  Molecular Weight : 40 g/mole  CAS Registry No. : 1310-73-2 Photographs :-

13. PHYSICAL AND CHEMICAL PROPERTIES :-  STATE : Liquid  APPEARANCE : Colorless or slightly turbid  ODOR : Irritating  pH : Strong base >14  BOILING POINT : 145°C for ~50% NaOH Solution  FLASH POINT : Not determined  SPECIFIC GRAVITY : 1.51-1.54  VAPOR PRESSURE : ~6.3 mm Hg @ 40°C  SOLUBILITY IN : WATER : miscible & ACID : miscible

14. Production Cost of Caustic Soda :-  The caustic soda is one chemical whose price fluctuation is very high. The price can vary from Rs 10,000 — Rs 18,000/ Ton. The price index fluctuation of caustic soda and chlorine for a period of 10 years (1994-2003) is depicted in the following graphs. It can be broadly stated that the price of the caustic soda is strongly influenced by chlorine, which is a co product. If the caustic demand grows at the same rate as chlorine, then the price of both the products will be stable. When the chlorine demand is less the caustic production has to be reduced, as chlorine is difficult to store and this situation increases the price of caustic, with reduction in chlorine price.

16. International Price of Caustic Soda :-  The price of caustic soda also fluctuates highly in the international market. During the last 8 years the price of caustic soda fluctuated from 90 US$ to 260 US$. The graph below represents the average price of the caustic soda during the corresponding years :

17. Producer & Location of manufacturing process in Gujarat & India :- Atul Products Ltd. P.O. Atul, Dist. Valsad ( Gujarat )Mercury Cell Gujarat Alkalies & Chemicals Ltd. P.O. Box Petrochemicals 391 346, Dist.Vadodara(Gujarat ) Mercury Cell Saurashtra Chemicals ( Unit of VXL India Ltd.) Birlasagar, Porbander ( Gujarat ) Chemical Process Ahmedabad Mfg. & Calico Printing Co. Ltd. (a)Ahmedabad (Gujarat) (b)Anik-Chembur, Bombay Diaphragm Process Mercury Cell Andhra Sugars Ltd. Kovvur – 534 350, Dist. West Godavari(A.P.) Mercury Cell Bihar Caustic & Chemical Ltd. Garhwa Road, Rehla – 822 124 Dist. Palamau (Bihar)Mercury Cell Century Chemicals (Units of Century Textiles & Industries Ltd.) Murbad Road, Kalyan (Maharashtra) Mercury Cell Chemfab Alkalies Ltd. Kalapet, PondicherryMercury Cell Durgapur Chemicals Ltd. Durgapur ( W.B.)Mercury Cell Grasim Industries Ltd. Nagda, Birlagram (M.P.)Mercury Cell

18. Hindustan Heavy Chemicals Khardah - (W.B.)Mercury Cell Jayshree Chemical Ltd. Ganjam ( Orissa )Mercury Cell J.K. Chemicals Ltd. Panchakadi, Thane (Maharashtra)Mercury Cell Kanoria Chemicals & Industries Ltd. Renukoot, Dist. Sonebhadra (U.P) Mercury Cell Modi Alkalies & Chemicals Ltd. SP-460, Matsya Industrial Area Alwar – 301 030 (Rajasthan) Mercury Cell National Rayon Corp. Ltd. Mohone – 421 102, Kalyan, Dist.Thane (Maharashtra) Mercury Cell Nepa Ltd. Nepanagar- 450 221 Dist. East Nimar (M.P.)Mercury Cell Panjab Alkalies & Chemicals Ltd. Nangal-Una Road, Naya Nangal- 140 126 Dist. Ropar (Panjab) Mercury Cell Rohtas Industries Ltd. Dalminagar (Bihar)Mercury Cell Southern Petrochemical Industries Corp.Ltd. SPIC Nagar, Tuticorin- 628 005 (T.N.) Mercury Cell Sree Rayalaseema Alks. & Allied Chems.Ltd. Vasant Nagar, Gondiparla Village – 518 004 Kurnool Dist. (A.P) Mercury Cell MercuryCell Standard Mills Co. Ltd. Ghandsoli, Thane (Maharashtra) Mercury Cell Travancore Cochin Chemicals Ltd. Eloor, Alwaye ( Kerala )Mercury Cell

19. Import-Export of Caustic Soda :-  As per the available data (2002-03), the total import of caustic soda is around 118098 Tons. This constitutes around 6.8% of the total domestic consumption during that year. The percentage break up of the total import of caustic is as given below…

20.  The import of caustic soda in India during the three years is depicted below:  The total export of Caustic soda by Indian companies during the year 2002-03 was 41804 Tons, which includes lye, flakes and prills.  As per the available data there is a decreasing trend in the import of caustic soda during the year 2003-04. One of the reasons for this may be the antidumping law against cheap import of caustic soda.

21.  During the study period in 2004-05 there were thirteen units operating with mercury cell technology. As mentioned earlier the mercury cell unit in the country has a capacity varying from 30 TPD to 240 TPD. The average installed capacity of different mercury cell units are depicted below…

22.  World production capacity of sodium hydroxide by region (total: 59 557 000 t in 2004)

23. References :- 1. S. U. Pickerring, J. Chem. Soc. 63 (1893) 890. 2. Gmelin, 8th ed., System no. 21. 3. S. A. McCluney, J. W. Van Zee, J. Electrochem. Soc. 136 (1989) 2556 – 2564. 4. C. B. Kelly, I. L. Walker, Staff of the Chlorine Institute, Inc. (eds.): The Second Chlor-Alkali Symposium, World Chlor-Alkali: An Industry in Transition, Proceedings, Washington, DC 1990. 5. D. C. Brandt, paper presented at the Chlorine Institute Meeting, Washington, DC, April 1989. 6. R. Winkler, Chem. Ind. 36 (1984) 152 – 155. 7. D. Hoormann, J. J¨orissen, H. P¨utter, Chem. Ing. Tech. 77 (2005), no. 9, 1363 – 1376. 8. Bayer MaterialScience AG, DE 101 48 599, 2001. 9. Toagosei, Mitsui Chem., Kaneka, Chlorine Engineers, EP 104 1176, 1998. 10. M. Kamaludeen et al., Transactions of the SAEST 21 (1986) no. 1, 53 – 56. 11. Ullmann, 3rd ed., 12, pp. 659 – 660.