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		Soap Production (CDI, 1995, 70 p.)
			(introduction...)
			1. INTRODUCTION
			2. GENERAL INFORMATION ON SOAP
			3. THE RAW MATERIALS
			4. THE MANUFACTURE OF SOAP
			5. THE TREATMENT OF OILS AND FATS
			6. SAPONIFICATION: COLD PROCESS
			7. SAPONIFICATION: SEMI-BOILED PROCESS
			8. SAPONIFICATION: FULL BOILED PROCESS
			9. SAPONIFICATION: CONTINUOUS PROCESS
			10. THE COOLING AND DRYING OF SOAP
			11. FINISHING SOAP
			12. PRODUCTION OPTIONS
			13. GENERAL CONSIDERATIONS FOR MANUFACTURING PROCESSES
			14. CDI EXPERIENCE IN SOAP FACTORY PROJECTS
			15. IMPLEMENTING A SOAP FACTORY PROJECT
			16. EQUIPMENT MANUFACTURERS
			17. TURNKEY SUPPLIERS AND ENGINEERING OFFICES
			18. THE SOAP MAKERS
			19. DEVELOPING A SOAP FACTORY PROJECT
			20. CHECKLIST: RAW MATERIALS
			21. CHECKLIST: THE SOAP MARKET
			22. CHECKLIST: DATA FOR A FEASIBILITY STUDY
			ANNEXES
			23. SERVICES OFFERED BY THE CDI
			OTHER TITLES
			BACK COVER

7. SAPONIFICATION: SEMI-BOILED PROCESS

Figure

The semi-boiled process differs from the cold process in the fact that the saponification mixture is heated to 70 - 90° C using a steam-heated coil to accelerate and complete the saponification reaction. Dyes, perfumes, and additives are added at the end of the process to prevent them from evaporating.

The process allows the quantity of soda undergoing saponification to be adjusted before the crude soap is drawn off. It also allows manufacturing waste to be recycled, better incorporation of the additives and a wider choice of raw materials. Generally speaking, saponification is more complete and the hardening time of crude soap in cooling frames is slightly reduced.

These various advantages, combined with shorter production cycles and reasonable production costs, make the semi-boiled process a flexible process which is particularly well-suited to developing countries. It is often used in industrial-scale production of widely marketed low-grade soaps.

As for the cold process, the semi-boiled process does not discharge any effluent into the environment.