Making Potassium Nitrate

Formula Weight

101.1032

Density

1.00g/mLat 20°C

"Earth explosive"

The scientific name for nitrate is potassium nitrate (KNO3). Potassium nitrate is a strong oxidizing agent that is easy to burn and explode, and it is commonly used by people to make earth explosives.

Making potassium nitrate is actually the process of extracting and crystallizing potassium nitrate from soil. During our visit to Shiyanping Village, we found an elderly person who had previously taken soil from a nitrate cave to produce nitrate. Based on the elderly person's description of the nitrate production process and relevant relics in the nitrate cave, we have restored his youth's nitrate production process and compared it with the nitrate production process recorded in literature of the same period.

1. Production of a nitrate tank: excavate the nitrate tank inside the nitrate tunnel, with the tank wall plastered with soil and locally built with blocks of stone. The nitrate tank is composed of a primary filter (large) and a secondary filter (small), and the two filters are connected by drainage holes.

2. Digging nitrate soil: digging nitrate soil inside the nitrate cave. The nitrate content in nitrate soil is higher than that in ordinary soil, and there is a layer of frost-like white crystals on the surface.

3. Pour the nitrate soil into the nitrate tank. Lay a layer of dry straw at the bottom of the primary filter, and then pour the nitrate soil multiple times. After each pour, compact the nitrate soil until it is about thirty centimeters away from the top of the primary filter. Pour water onto the nitrate soil: Take clean water from the water channel inside the nitrate cave and slowly pour it into the primary filter.

4. Excavate the residual soil in the filter: After five hours of watering, excavate the residual soil in the primary filter, pour it back into the residual soil, and water it.

5. Take the nitrate water home. Due to the need for fire in the subsequent steps and poor air circulation in the nitrate cave, complete the subsequent steps at home.

6. Heat and boil nitrate: Pour nitrate water into an iron pot and bring to a boil. Add alkaline water made by burning local palm tree stems to ashes and mixing it with water. Cook over high heat for half an hour and filter. Filter out impurities and bring to a boil. Add alkaline water again and cook over high heat for half an hour.

7. Obtaining finished soil nitrate: After sufficient cooling, a layer of ice-like solid precipitates on the surface, which is called soil nitrate. There is a clear layering between the soil nitrate and the underlying solid. Gently peel it off, store it in a dry place, and take it anytime you use it.