Reference request on formate potash process
The reference is correct, from [1, p. 888]:

Potassium formate: $\ce{HCOOK},$ colorless, deliquescent, rhombic crystals; $M_\mathrm{r}~84.12,$ density $1.91$, m.p. $\pu{167.5 °C}.$ P. is formed by neutralization of aqueous formic acid with potassium hydroxide or potassium carbonate. It is an industrial intermediate in the formate-potash process (see Potassium carbonate).

However, formate-potash process doesn't yield in elemental potassium, rather potassium carbonate [1, p. 886–887]:

Potassium carbonate, potash:
[…]
P. is also produced by the formate-potash process, in which potassium sulfate and lime are treated under pressure with carbon monoxide:
$$\ce{K2SO4 + Ca(OH)2 + 2 CO -&gt; 2 HCOOK + CaSO4}.$$
The resulting potassium formate is oxidized to P. by heating it in air:
$$\ce{2 HCOOK + O2 -&gt; K2CO3 + CO2 + H2O}.$$

English Wikipedia page claims formate-potash process is for “production of potassium” probably because the author attributed “P.” from the encyclopedia entry to potassium.
Whereas in reality it refers to the entry title, “Potassium carbonate”, which is a standard referencing method in data sources such as a handbook or an encyclopedia.
German Wikipedia page doesn't have this flaw and informs that “Formiat-Pottasche-Verfahren” is a technically insignificant method of producing $\ce{K2CO3}.$
References

Concise Encyclopedia Chemistry, English language ed., 2nd ed.; Scott, T., Eagleson, M., Eds.; de Gruyter: Berlin; New York, 1994. ISBN 978-0-89925-457-9.