1. Product Description: Oxalic acid which is the simplest dicarboxylic acid is an important organic chemical having wide applications in various industries such as textile, dye-stuff, pharmaceuticals and other. It occurs naturally in many plants like wood sorrel, rhubarb, spinach …etc. Oxalic acid used in the textile industry centers upon its calcium iron removal and reducing properties and as such it is widely used as bleach for removing iron stains. The product also finds applications in automobile radiator cleanser. In dye-stuff industry, it is mainly used as an intermediate substance. It is a starting raw material for the manufacture of diethyl oxalate which in turn is being used as a starting raw material for the manufacture of sulphame thaxazole which is the latest sulpha drug used in combination with trimethoprim in various formulations and has broad spectrum antibacterial range. Oxalic acid also finds use as a purifying agent, as a catalyst, as a stripping agent for permanent press resins and also in the processing of rate earths. In short, oxalic acid is used for metal and equipment cleaning, as chemical intermediates for textile finishing and cleaning, in leather tanning and for miscellaneous purposes like purifying agent, a catalyst, stripping agent for permanent press resins, etc.
2. Market Potential:- All the chemical inputs of the textile, leather tanning, metal, chemical industries are imported which is a manifestation of the low level of industrial development of the country. There very weak linkages between branches of the manufacturing industry which makes the industry much dependent on foreign inputs such as chemicals. Oxalic acid which can be manufactured using domestic inputs is one of those chemical products which is imported. An annual import of this product is to the tune of more than 50,000 tons. With the expansion of the above industries, the demand for the oxalic acid will grow. The Amhara Region has its share of textile industries. A few tanneries are established which may constitute the foundation of a leather processing industries. In addition to the regional demand, the national demand for oxalic acid could justify the establishment of a plant which can produce this chemical product.
3. Source of raw material: Oxalic acid is prepared by the oxidation of carbohydrates such as glucose, sucrose (sugar), starch, dextrin and cellulose by nitric acid. The alkali (Potassium and sodium hydroxides) fusion of carbohydrates also yields oxalic acid. The fusion method is particularly applicable in the utilization of waste cellulosic materials such as saw dust, corn cobs, cornstalks and oat halls. These raw materials can be collected from various areas within the Region.
4. Process and Technology: The production process described here uses sugar/molasses/jaggery and nitric-sulphuric acid mixture as the basic raw materials. "Mother liquor (consisting of residual oxalic acid, sulphuric acid, nitric acid and catalyst) of previous batch is taken into reactor". To this sulphuric acid is added which increases the temperature of reactor. The increased temperature is brought down with chilled water circulation through the cooling coils. Then nitric acid is added into the reactor. After this, sugar is added very slowly to avoid rapid increase in temperature and the rate of adding sugar increases gradually. Oxides of nitric acid generated during reaction are absorbed in a series of three absorbers using counter current principle. Oxalic acid obtained after centrifuging is then further purified by recrystallization using water a solvent. Then recrystalized material is again centrifuged and dried. Basic equipment required include storage tanks, mother liquor tanks, pumps, feed vessels, reactors, absorption columns, centrifuges, dissolving tanks, crystallizers.
5. Estimated Investment: For a plant that will produce 300 tons of oxalic acid, the estimated investment will be:-
Ø Buildings/shades 500 m2 at Birr 2500/m2 = Birr 1,250,000
Ø Machinery and equipment..................... = Birr 14,000,000
Ø Working capital..................................... = Birr 2,000,000
Total = Birr 16,250,000
6. Benefits: Saves foreign exchange, supports other industrial sectors, has the potential of generating income to the Region.
7. Location: Combolcha, Debre Birahn.