In industry, the alkali dissolution and acid precipitation method is often used to prepare potassium humate using lignite and weathered coal as raw materials. The humic acid in peat is dissolved and replaced in the form of humate using strong alkali.

The preparation of potassium humate is to treat the raw materials with a certain concentration of potassium hydroxide solution and separate them by suction, and then evaporate the obtained potassium humate solution. 

The reaction principle is as follows:

R(COOH)n+nKOH→R(COOK)n+nH2O

Potassium humate is easily soluble in water, and its aqueous solution is alkaline. It is a black or dark brown solid with a slightly metallic luster. It has the characteristics of humic acid and has functions such as ion exchange, adsorption, peptization, and complexation.

The potassium content in plants varies depending on the type of plant and the different organs of the plant. Potassium humate fertilizer can not only promote the absorption and utilization of potassium by plants, but also build a reasonable potassium distribution structure and increase the potassium content of agricultural products. Potassium humate has multiple functions of high utilization rate, accelerated release and slow release, because the functional groups of humic acid can absorb and store potassium ions to prevent leaching and loss.

Compared with inorganic potassium fertilizers, potassium humate is rich in humic acid and has a certain cation exchange capacity. 

The potassium in it can supplement the potassium source of crops.

 Humic acid can activate the potassium fixed in the soil, promote the release of soil potassium, and prevent the soil from fixing potassium. In addition, humic acid can dissolve mineral oils such as potassium silicates and potassium feldspar, slowly decompose and increase the release of potassium, and improve the content of quick-acting potassium.