The lead chamber is no longer cube-shaped, because the cube will form corners, and the material may be stagnant in these corners. The flow rate of the air flow is very slow, and the repeated contact efficiency between the gas phase and the liquid phase of the tiny droplets is very poor, so gradually

Transformed into a cylindrical or frustoconical shape, the shape becomes a tower.

The lead chamber is no longer empty, but filled with porcelain beads. This can increase the contact surface of the reactants.

The frame is no longer wood, but steel, and even lead plates have been replaced by iron and steel, which are as resistant to sulfuric acid corrosion as lead, and are lined with acid-resistant bricks or orthoclase to further enhance corrosion resistance.

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In this way, the lead chamber method becomes the tower method, but the chemical principles of sulfuric acid production are still the same.

The chemical principle of making sulfuric acid by the contact method is different. The contact method, also known as the catalyst method or catalytic method, began in 1831. In this year, Phillie, a vinegar manufacturer in Bristol, a port city in southwest England,

Phillips Peregrine submitted a patent application to the government. The project was to "save the cost of saltpeter and vitriol lead chambers." The content was to use platinum powder as a catalyst to directly oxidize sulfur dioxide to sulfur trioxide by oxygen, and then make the trioxide

Sulfur dissolves in water to form sulfuric acid. However, this method was not immediately put into practical production because the platinum powder was quickly rendered ineffective by the impurities contained in the sulfur dioxide. It was not until 1875 that a chemist named Mai, who was born in Germany and had lived in England for a long time,

Messel (Rudolph 1848-1920) proposed that the sulfur dioxide and oxygen should be purified first, so that the platinum powder can remain effective for a certain period of time, so that the sulfur dioxide and oxygen can be made into SO3 under the catalysis of platinum asbestos, and can be absorbed by ordinary sulfuric acid to produce smoke.

Sulfuric acid. In 1881, the British sulfuric acid manufacturer Squires W.S. applied for a patent for this method and built a factory for production. Messer participated in the work.

Winkler (Clemens Alexander 1838-1904), the German chemist who discovered the element germanium, also conducted experiments in 1875 to synthesize SO3 by combining SO2 with oxygen in the presence of platinum.

However, platinum is expensive and easily poisoned, prompting sulfuric acid manufacturers and chemists to search for cheaper catalysts. By the 1920s, catalysts such as vanadium oxide and iron oxide appeared. Almost all modern contact method sulfuric acid manufacturing
Chapter completed!