Objective To reveal the potassium (K⁺) adsorption properties of diatomite and tailings from Linjiang, Jilin Province, and provide theoretical basis for the development and utilization of diatomite and tailings as soil K⁺ regulation materials.

Method High quality diatomite raw ore and tailings were collected in Linjiang, their chemical and mineral compositions were analyzed, and their K⁺ adsorption and desorption characteristics were studied by static equilibrium adsorption method.

Result The high quality diatomite and tailings were considerably different in their SiO₂ contents which were 78.57% and 89.29% respectively. Both were mainly composed of amorphous opal, yet only tailings contain some impurities such as quartz, kaolinite, mica and organic matter. The kinetic adsorptions of K⁺ by both high quality diatomite and its tailings were in accordance with pseudo two order kinetics model. The thermodynamic adsorptions of K⁺ by both were consistent with the Freundlich isotherm adsorption equation, and the adsorption reactions were easy to carry out. The K⁺ desorptions by both were consistent with the Elovich equation. The K⁺ desorption rates and the logarithmic values of reaction time (Lnt) were well linearly correlated before the desorption process reached equilibrium for both the high quality diatomite and tailings.

Conclusion Diatomite tailings are mainly composed of amorphous opal, and has certain capacity of K⁺ adsorption and desorption.