Lowayu village is a village in Dukun sub district in Indonesia where most of the people have lime stone industry to be used as limestone or lime, now the local people still sell their products of limestone which still have low economical value so that need further processing in order to obtain products that are more economically valuable than limestone in the form of caustic soda (NaOH).
Sodium hydroxide (NaOH), also known as caustic soda and belonging to the alkaline earth group, is a base metal caustic. NaOH is used in many industries, primarily as a strong base in the manufacture of pulp and paper, textiles, drinking water, soaps and detergents and as a dirt cleaner produced worldwide in 1998 is about 45,000,000 tons. Sodium hydroxide is a common basic ingredient in chemical laboratories. NaOH is highly soluble in water by freezing heat, pure sodium hydroxide is a white solid, in pellets, shapes, granules and as a 50% saturated solution it is hygroscopic and readily absorbs water from the air, so it should be kept in an airtight place. NaOH is also soluble in ethanol and methanol, although solubility capability in the solvent is lower than potassium hydroxide. NaOH is insoluble in ether and other non-polar solvents.
A sodium hydroxide solution will leave a yellow stain on the fabric and paper. NaOH is often referred to as caustic soda, made by way of, Reaction of Na metal with water This method is risky because Na metal is explosive. In NaOH industry is made by Casserification of sodium carbonate salt and salt electrolysis, soda caustic widely used for the purposes of : Blenching, dyeing, oil refining Soap and paper industry, bauxite refining, industrial aluminum, artificial silk making, dye formation such as alizarin. One way of making NaOH is by using kaustifikasi salt Sodium Carbonate ie reacting between sodium carbonate with calcium oxide or often referred to as burning lime
The purpose of writing is
1. Showing one of the process of making NaOH from lime
2. Calculate the economics of the selling value of NaOH production in comparison with CaO selling price
1. Process of Making NaOH with Causticated Salt Method of Sodium Carbonate
In this study the authors do the synthesis of NaOH from limestone (CaO) This study aims to synthesize NaOH and determine the levels of NaOH formed from limestone (Lime) from the owner of limestone burning (big stove) villagers Lowayu Dukun Gresik Indonesia.Sebanyak 6 grams of powder CaO with 100 ml of aquades little by little so as to form a porridge of Ca(OH)2.
In addition to forming Ca(OH)2, the mixing of CaO with aquades aims to make the CaO that formed the solution more reactive because the liquid form so easily react with Na2CO3 solution. Then prepared a solution of Na2CO3 by dissolving 10.6 grams of Na2CO3 powder into 100 ml of aquades while heated.
Heating is done to facilitate the powder Na2CO3 dissolve in aquades. Furthermore, the Ca(OH)2 slurry is mixed into Na2CO3 solution while remaining heated. he equation of the reaction occur is
CaO(s) + H2O(l) → Ca(OH)2(aq)
Na2CO3(aq) + Ca(OH)2(aq) → 2NaOH(aq) + CaCO3(s)
The obtained NaOH solution, solution then tested for its acidity by using a universal indicator. It is known that the pH of NaOH solution is 13.
This shows that the obtained NaOH solution is a very strong base. Testing of subsequent NaOH filtrate using CUSO4 solution, CuO black deposits are formed when the NaOH filtrate is added to CUSO4 solution while heated. At first when the NaOH filtrate was incorporated into CUSO4 solution formed a light blue precipitate which was a precipitate of Cu(OH)2
2NaOH(aq) + CuSO4(aq) → Cu(OH)2(s) + Na2SO4(aq)
Since the heating applied to the mixture causes the water content contained in the Cu(OH)2 precipitate to evaporate to form Cu which is brown and directly oxidized to CuO which is a black precipitate according to
Cu(OH)2(s)→ Cu ( s) → CuO (s)
Furthermore, to determine the levels of NaOH obtained, done titration of NaOH solution using Titran HCl 1 M.
Append 3 drops pp indicator added to NaOH solution, thus formed a pink solution. Titration is done until the color changes in NaOH solution from pink to clear color. The titration was diluted 3 times and the HCl volume was used 11.1 ml, 10.9 ml and 11.0 ml respectively. From the average data, it is found that the concentration of NaOH obtained is 1.10 M.
2. Economic Calculation of NaOH Sale of Synthesis Result
Calculation of the cost of NaOH synthesis with CaO can be detailed as follows (calculation for per kilogram of prescription used)
The price of CaO Rp 600 @ Kg Þ 6 Kg x Rp 600 = Rp 3.600
The price of Na2CO3 Rp 45.000 @ kg Þ10,6 Kg x Rp 45.000 = Rp.477.000
Harga aquades @liter Rp.5.000 Þ200 liter x 5.000 = Rp.1.000.000
The total of production fee NaOH is Rp.1.480.600.
From Cv Sindo (Cahaya Kimia Surabaya) the price NaOH 1M @ 1 liter Rp 35.000
if the buy price is Rp.30.000
so we get Rp.30.000 x 200 liter = Rp.6.000.000
If we produced NaOH 180 liters
we result Rp.30.000 x 180 liter = Rp.5.400.000.
So we get Rp.5.400.000
The profit will get
Rp.5.400.000 – Rp.1.480.600 = Rp. 3.919.400
From the calculation results in the production profit of each Kg of recipes is Rp.3.919.400 a considerable advantage when compared with selling in the form of direct CaO as did the village community Lowayu Dukun Gresik at this time