Manufacturing Method of Potassium Hydroxide
Potassium hydroxide (KOH) is an important inorganic chemical raw material, which is widely used in the fields of chemical industry, medicine, foodstuff and light industry. This article will introduce the manufacturing method of potassium hydroxide.
I. Manufacture of potassium hydroxide by alkali method
Manufacture of potassium hydroxide by alkali method is one of the commonly used production methods, which mainly includes the following steps:
1. Mix potassium chloride and sodium carbonate evenly in a certain proportion, and add them into the reactor.
2. At a certain temperature, pass steam to carry out the reaction to produce sodium bicarbonate and potassium chloride.
3. The reaction solution is filtered and the crystals of sodium bicarbonate and potassium chloride are separated.
4. The filtrate is treated with calcium hydroxide to convert the sodium bicarbonate into calcium carbonate and sodium hydroxide.
5. The filtrate was again filtered to separate the calcium carbonate and sodium hydroxide solution.
6. A quantity of potassium chloride is added to the sodium hydroxide solution so that it reacts to form potassium hydroxide and sodium chloride.
7. The reaction solution is evaporated and concentrated to crystallize potassium hydroxide.
The reaction equation for the manufacture of potassium hydroxide by alkali method is as follows:
KCl + Na2CO3 → NaHCO3 + KCl
NaHCO3 + Ca(OH)2 → CaCO3↓ + NaOH + H2O
NaOH + KCl → KOH + NaCl
II. Electrolytic method of manufacturing potassium hydroxide
Electrolytic method is also one of the commonly used methods of potassium hydroxide manufacturing, which mainly It includes the following steps:
1. Dissolve potassium chloride in water to make a saturated solution. In an electrolytic cell, nickel is used as the anode and iron as the cathode, and direct current is applied for electrolysis.
3. At the cathode, hydrogen ions are reduced to hydrogen gas by gaining electrons while the concentration of hydroxide ions increases to produce potassium hydroxide.
4. At the anode, chloride ions lose electrons to oxidize to chlorine gas.
5. The rate and purity of potassium hydroxide production is controlled by adjusting the current and electrolyte concentration.
6. The electrolyte is evaporated and concentrated to crystallize potassium hydroxide.
The reaction equation for manufacturing potassium hydroxide by electrolysis method is as follows:
2KCl + 2H2O → 2KOH + Cl2↑ + H2↑
3. Other manufacturing methods
Besides alkali and electrolysis methods, there are also some other methods for manufacturing potassium hydroxide, such as:
1. Lime milk method: Potassium chloride is reacted with lime milk to generate potassium hydroxide and calcium chloride, and then potassium hydroxide is obtained by separating and crystallizing.
2. Potassium carbonate method: React potassium carbonate with calcium hydroxide to form potassium hydroxide and calcium carbonate, then separate and crystallize to obtain potassium hydroxide.
4. Precautions
In the process of manufacturing potassium hydroxide, the following matters need to be paid attention to:
1. Control the reaction temperature and reaction time to avoid the generation of by-products or affecting the quality of the product.
2. Adjust the pH value of the solution to ensure the smooth progress of the reaction.
3. The material and sealing of the equipment should be good to avoid corrosion and leakage.
4. Pay attention to safety during operation, avoid contact with skin, eyes and so on.
All in all, there are various manufacturing methods of potassium hydroxide, and different methods have different advantages and disadvantages and scope of application. In actual production, the suitable method should be selected according to the specific situation and the operation process should be strictly controlled to ensure product quality and production safety.
