Abstract:
Fertilizers are defined in the broadest sense as products that improve the
levels of available plant nutrients or chemical and physical components that
directly or indirectly enhance plant growth, yield and quality. The aim of this
study was to produce slow controlled release fertilizers from oxidised coal.
Two types of coals namely, Waterberg and Twistdraai (products, middlings)
were utilised for the production of humic acids through slurry phase oxidation.
The highest yields of humic acids were obtained in Waterberg and Twistdraai
products samples. Subsequent to that, a nitrogen element was successfully
inserted into the humic acid substrate. Humic acids are potential feedstock for
modern manufacturing of organic fertilizers. The chemical substances
regarded as hazardous to human consumption or those elements that
negatively impact on the soil were significantly less detectable.
