In the form of what compounds do the metals potassium, magnesium, chromium and zinc occur in nature?

In the form of what compounds do the metals potassium, magnesium, chromium and zinc occur in nature? Write down the chemical formulas for these compounds. How can these metals be obtained in free form? Give the corresponding reaction equations.

Potassium.
In nature, in minerals (mica, sylvin KCL) and seawater, in ash after combustion of plants (K2CO3).
2 KCl = 2K + Cl2 (by electrolysis of the melt at high temperatures).
KCl + Na = NaCl + K (reduction with metallic sodium).
K2CO3 = 2K + CO + O2 (by electrolysis of the melt at high temperatures).

Magnesium.
In nature, in minerals (carnalite MgCl2 * KCl * 6H2O, bushfort MgCl2 * 6H2O, dolomite CaCo3 * MgCO3) and seawater.
MgCl2 = Mg + Cl2 (by electrolysis of the melt at high temperatures).

CaCo3 * MgCO3 = СaO + MgO + 2CO2, then add silicon and get:
СaO + 2MgO + Si = CaSiO3 + 2 Mg or:
MgO + C = Mg + C (magnesium coking at high temperatures)

Chromium.
In nature, in minerals (chromite Fe (CrO2) 2, crocoite PbCrO4.
Fe (CrO2) 2 + 4C = Fe + 2Cr + 4CO (coking – industrial method)

It is also possible by carrying out 4 reactions, but this method has not been applied:
PbCrO4 + 3NaOH = Na (Pb (OH) 3) + Na2CrO4
2Na2CrO4 + H2So4 = Na2CrO7 + H2O + Na2So4
Na2CrO7 + 2C = Cr2O3 + Na2Co3 + CO
Cr2O3 + 2 Al = Al2O3 + 2 Cr

Zinc.
In nature, in minerals (zincite ZnO, smithsonite ZnCO3, zinc sulfide ZnS).
ZnO + C = Zn + CO (coke reduction)
2ZnS + 3O2 = 2 ZnO + 2 SO2 (then coke according to the previous equation)