Research on the possibilities of utilizing several waste substances for the production of suspension fertilizers has been carried out. The substances were: sludge from the ALWERNIA S.A. Chemical Plant - a potential source of phosphorous (~20% by wt. P2O5) and waste sludge from the production of magnesium sulphates and nitrates in the Złotniki S.A. Chemical Plant - a substance aiding the stability of suspension and magnesite (a source of magnesium). The possibility of chemical activation of clayey minerals through ion exchange was investigated. Na2CO3 was used for this purpose. Fertilizer samples PK and NPK were found to be highly stable (syneresis < 25%). The NPK +3% MgO sample was found to have particularly good properties. The activation of the clayey materials by Na2CO3 resulted in an increase in the stability coefficient in the case of bentonite SN and clay TIK by 0.88964 and 0.516304, respectively.