Carnallite-Derived Solid Waste as Potassium (K) and Magnesium (Mg) Source in Granulated Compound NPK Fertilizers

Abstract

Principles of green engineering require that material inputs are renewable. To this regard, a partial or a full substitution of one of the feedstocks with the waste from other industries can minimize the environmental impacts. Potash rock is a source of a key potassium (K), but its environmental impacts, including land use and greenhouse gas emissions during the mining and beneficiations, are of concern. Carnallite rock is used to electrochemically produce elemental magnesium (Mg) and yields solid sludge waste with K2O content of ∼43% and Mg content of 2.0%.This carnallite-derived waste is characterized physically and chemically and utilized to manufacture compound NPK fertilizers. The mesoporous waste material structure was found which facilitated the wet granulation process in spite of low 6 m2/g measured surface area. Trace metal concentrations measured were low and did not pose significant limitations from the regulatory point of view. Several high-K2O-content fertilizer formulations were proposed and granulated using both laboratory and industrial wet granulation in a rotary drum. Large K2O amount from the carnallite processing waste, up to 10 times that from mined KCl, was utilized in these fertilizers. The sustainability impact of the overall process was assessed by evaluating the averted greenhouse gas (GHG) emissions when carnallite-derived waste was substituted for potash rock. It was found that up to 5000 t of CO2/year per 100 000 t/year NPK 10-20-20 fertilizer can be avoided if waste is used rather than the potash rock.

Sulfur Tolerant Subnanometer Fe/Alumina Catalysts for Propane Dehydrogenation

“…The surface areas of the catalysts were measured via nitrogen physisorption (−196 °C) using a Micromeritics ASAP 2020 instrument. 34 Pore size distributions were calculated using the Barret, Joyner, Halenda (BJH) model. 35 2.4.…”

Heterogeneity in the Chemical Composition of Biofertilizers, Potential Agronomic Use, and Heavy Metal Contents of Different Agro-Industrial Wastes

“…On the other hand, composted chicken bed obtained by Mekki et al [39] presented lower levels of K compared with the main sources of this nutrient in the present study (ash and seed meal residue). In agriculture, potassium rocks are the main source of potassium used in the manufacture of fertilizers, but their environmental impacts, including the use and emissions of greenhouse gases during mining, are of concern [55]. In 2010, Brazil imported approximately 90% of this mineral [56].…”

High-Efficiency Reclaiming Phosphate from an Aqueous Solution by Bentonite Modified Biochars: A Slow Release Fertilizer with a Precise Rate Regulation

“…1−4 To date, a variety of slow release fertilizers have been developed, including coated fertilizers, 5−9 matrix-based fertilizers, 10,11 chemically bonded fertilizers, 12 and compoundtype fertilizers. 13,14 As for these slow release fertilizers, the attachment of fertilizers in a suitable carrier or coating material is necessary. Recently, biochar has emerged as one of the most promising carrier materials for slow release fertilizers, owing to its unique characteristics such as large surface area, porous microstructure, and versatile surface chemistry.…”

“…Slow release fertilizers have gathered tremendous interest for their potentials in solving the low utilization efficiency and environmental issues associated with conventional fertilizers. − To date, a variety of slow release fertilizers have been developed, including coated fertilizers, − matrix-based fertilizers, , chemically bonded fertilizers, and compound-type fertilizers. , As for these slow release fertilizers, the attachment of fertilizers in a suitable carrier or coating material is necessary. Recently, biochar has emerged as one of the most promising carrier materials for slow release fertilizers, owing to its unique characteristics such as large surface area, porous microstructure, and versatile surface chemistry. , In addition, the use of biochar as a nutrient carrier potentially offers the benefits not only of supplying the essential nutrients for plants in a slower mode compared with traditional fertilizers but also of soil amendment such as enhanced cation exchange capacity and water holding capacity. , Given that biochar has been demonstrated as an effective adsorbent for the remediation of nutrients (e.g., phosphate and ammonium) contaminated wastewater, − it is believed that biochar can provide a platform for reclaiming nutrients from wastewater to act as a slow release fertilizer to promote the growth of plants. , As for biochar based slow release fertilizers (BSRFs) which reclaim nutrients from aqueous solutions, to further advance their developments toward practical application, it is essential to improve the adsorption capacity of the used biochar for nutrients in aqueous solutions.…”