The laboratory preparation of tetraoxosulfate(VI) acid, also known as sulfuric acid (H2SO4), involves a process called the contact process. The steps for the laboratory preparation of sulfuric acid are as follows:

1. Sulfur dioxide (SO2) production: Sulfur (S) is burned in an excess of dry air to produce sulfur dioxide gas according to the equation:
   S(s) + O2(g) → SO2(g)
2. Conversion of sulfur dioxide to sulfur trioxide: The sulfur dioxide gas is then oxidized to sulfur trioxide (SO3) by passing it through a catalyst bed of vanadium(V) oxide (V2O5) at a temperature of about 450-500°C:
   2SO2(g) + O2(g) ↔ 2SO3(g) (catalyst: V2O5)
3. Absorption of sulfur trioxide: The sulfur trioxide gas is passed into concentrated sulfuric acid (H2SO4) to form oleum (H2S2O7):
   SO3(g) + H2SO4(l) → H2S2O7(l)
4. Dilution of oleum: The oleum is then diluted with water to produce concentrated sulfuric acid:
   H2S2O7(l) + H2O(l) → 2H2SO4(l)

It is important to note that this process requires careful handling due to the corrosive and hazardous nature of sulfuric acid. Proper safety precautions and laboratory practices must be followed when performing these procedures.
Please keep in mind that the laboratory preparation of sulfuric acid should only be conducted by trained professionals in a well-equipped laboratory, as it involves potentially dangerous chemicals and processes.