Anti-Caking Coatings for Improving the Useful Properties of Ammonium Nitrate Fertilizers with Composition Modeling Using Box–Behnken Design

Granular fertilizers (especially those based on ammonium nitrate (AN)) tend to agglomerate during storage. The aims of this research were to develop effective anti-caking coatings for ammonium nitrate fertilizers while improving the quality of fertilizers and to optimize the composition of effective anti-caking coatings. The influence of the composition of the prepared organic coatings on the effectiveness of preventing the caking of fertilizers was studied by response surface methodology (RSM) using Box–Behnken design (BBD). Additionally, the effect of the developed anti-caking agents on the quality of fertilizers was determined by measuring the crushing strength of the granules. The prepared coatings included fatty amine, stearic acid, surfactant, and paraffin wax. Gas chromatography–mass spectrometry (GC–MS) was used to analyze these coatings. The morphology of the fertilizers were examined by scanning electron microscopy (SEM). Composition studies, based on statistical assessment, showed the coating components had a varying influence on preventing the caking of fertilizers after granulation and after 30 days of storage. The results demonstrated that increasing the content of fatty amines and reducing surfactant in the composition of coating had positive effects on caking prevention. In this study, more effective and economically viable anti-caking coatings were developed. In addition, the present work could serve as a basis to further improve anti-caking coatings.

Application of Octadecylamine-Based Adsorbent on Carbon Dioxide Capture

Porous surface of silica gel (SG) have been modified with alkyl fatty amine compounds (octadecylamine, ODA) via wet impregnation process. The ODA-based adsorbents were physically characterized by XRD. The presence of crystalline peaks on ODA/SG diffractograms were ascertained the well-dispersion of ODA on the SG surface. XRD analysis displayed the increasing intensity of crystalline ODA with higher percent amine loaded and shifting of the several crystalline peaks of ODA verified the interaction of SG600-ODA. Capacity of CO2 capture by prepared solid adsorbents were evaluated using CO2 adsorption-desorption isotherms. This study shows that increasing percentage of ODA were improved the amount of CO2 uptake by following this trend: 35ODA/SG > 25ODA/SG > 15ODA/SG > SG > 5ODA/SG. However, promotion of 5 wt.% ODA unabled to enhance the capacity of CO2 captured due to pore blockage and reduction in SG pore surface, thus hindered the physisorption between CO2 and SG.

Flotation Studies on Low-Grade Phosphate Rock of Tarnawai, District Abbottabad, KPK Province, Pakistan

A low-grade siliceous sedimentary phosphate rock assaying 22.05% P205 was upgraded by double float (direct and reverse) technology. The rock contains collophane (carbonate fluorapatite) as the valuable phosphate mineral along with siliceous, carbonaceous and clay minerals. A process was developed which yielded a high-grade phosphate concentrate with improved recovery rate. The developed process consists of three parts. The first part includes wet grinding of ore to liberation point followed by separation of fines (slimes) by cone classifier. The finely ground deslimed ore was floated by direct anionic flotation using oleic acid collector to get rougher phosphate concentrate. It was cleaned once using additional quantity of reagents. In the second part, the fines generated during grinding operation were floated by column flotation to recover phosphate values. The cleaned concentrate and column concentrate were mixed together and washed thoroughly with hot water to remove the attached reagents. The final part comprises of cationic flotation of combined phosphate concentrate with fatty amine collector to float away quartz and silicates and to leave behind phosphate values. The grade of final phosphate concentrate was found to be 32.85% P205 with an overall recovery of 88.14%. The concentrate obtained meets the specifications of fertilizer and acid grade.

Hydrophobilization of Furan-Containing Polyurethanes via Diels–Alder Reaction with Fatty Maleimides

We describe new hydrophobic functionalized linear polyurethane resins by combining N-alkyl maleimides via the Diels–Alder reaction with linear furan-modified polyurethanes. This procedure provides the opportunity for the post-polymerization-functionalizing of polyurethanes. Access to furan-bearing polyurethanes is achieved via the reaction of a furan-containing diol, polyethylenglycol (PEG), and different diisocyanates. The furan-containing diol is obtained from the reaction of furfurylamine and two equivalents of hydroxyalkyl acrylate. The resulting furan-bearing polyurethanes are reacted with fatty amine-based N-alkyl maleimides. The maleimide and furan functionalities undergo a Diels–Alder reaction, which allows for the covalent bonding of the hydrophobic side chains to the polyurethane backbone. The covalent bonding of the hydrophobic maleimides to the polyurethane backbone is proven by means of NMR. The influence of the functionalization on the surface properties of the resulting polyurethane films is analyzed via the determination of surface energy via the sessile drop method.