The development road of ammonium phosphate fertilizer in China

Ammonium phosphate fertilizer is the compounds containing nitrogen and phosphorus that are usually produced through the neutralization reaction of phosphoric acid and ammonia.At present,there are a variety of products,such as slurry monoammonium phosphate(MAP),diammonium phosphate(DAP),industrial grade MAP,water soluble MAP,water soluble ammonium polyphosphate(APP)and so on.After more than 60 years of development,China’s ammonium phosphate fertilizer industry has experienced the road of from scratch and from weak to strong.The successful development of the slurry MAP technology ended the history that the high concentration phosphate fertilizer cannot be produced by using the medium and low grade phosphate ore.The continuous,stable and large-scale production of DAP plant provides sufficient guarantee for DAP products in China.The development of new ammonium phosphate fertilizer products,such as industrial grade MAP,water soluble MAP,water soluble APP,provides technical support for the transformation and upgrading of phosphorus chemical enterprises.In this paper,the production methods,the development history and the latest research progress of ammonium phosphate fertilizers were reviewed.

Leaching calcium from phosphogypsum desulfurization slag by using ammonium chloride solution: Thermodynamics and kinetics study

Phosphogypsum(PG) desulfurization slag is a calcium-rich residue from reductive decomposition of PG using sulfur as the reductant. We proposed a technology of preparation light calcium carbonate with PG desulfurization slag, which mainly contains two steps: leaching and carbonizing. In this work, we concentrated on the former, in which ammonium chloride aqueous solution was utilized as leaching agent to extract calcium from the slag, and conducted thermodynamics and kinetics study on it. Fact Sage software was employed to do thermodynamic and phase equilibrium diagram calculations. The influence of leaching conditions including agitation speed, initial concentration of leaching solution, reaction temperature, and liquid/solid ratio on the calcium leaching rate was discussed in detail by means of experiment optimal design. A kinetic model developed from the shrinking core model was given to describe the leaching process. The apparent kinetic activation energy(Ea) of the leaching reaction was calculated to be 10.58 kJ·mol^-1.

Fe-Nx Sites enriched microporous carbon nanoflower planted with tangled bamboo-like carbon nanotube as a strong polysulfides anchor for lithium-sulfur batteries

Serious shuttle effect and sluggish conversion kinetics of lithium polysulfides(LiPSs)have a massive impact on obstructing the practical application of lithium-sulfur(Li-S)batteries.To address such issues,Fe-Nx sites enriched microporous nanoflowers planted with tangled bamboo-like carbon nanotubes(Fe-Nx-C/Fe_(3)C-CNTs NFs)are found to be effective catalytic mediators with strong anchoring capabilities for LiPSs.The bamboo-like carbon nanotubes catalyzed by Fe_(3)C/Fe entangled each other to form a conductive network,which encloses a flowerlike microporous carbon core with embedded well-dispersed Fe-Nx active sites.As expected,electrons smoothly transfer along the dense conductive bamboo-like carbon network while the flower-like carbon core consisting of micropores induces the homogeneous distribution of tiny sulfur and favors the lithium ions migration with all directions.Meanwhile,Fe-Nx sites strongly trap long-chain LiPSs with chemical anchoring,and catalyze the redox conversion of LiPSs.Due to the aforementioned synergistic effects,the S@Fe-Nx-C/Fe_(3)C-CNTs NFs cathode exhibited a remarkable specific capacity(635 mAh g_(s)^(-1))at 3 C and a favorable capacity decay with 0.04%per cycle even after 400 cycles at 1 C.

An Approach towards Synthesis of Nanoarchitectured LiNi1/3Co1/3Mn1/3O2 Cathode Material for Lithium Ion Batteries

To explore advanced cathode materials for lithium ion batteries(LIBs),a nanoarchitectured LiNi_(1/3)Co_(1/3)Mn_(1/3)O_(2)(LNCM)material is developed using a modified carbonate coprecipitation method in combination with a vacuum distillation-crystallisation process.Compared with the LNCM materials produced by a traditional carbonate copre-cipitation method,the prepared LNCM material synthesized through this modified method reveals a better hexago-nal layered structure,smaller particle sizes(ca.110.5 nm),and higher specific surface areas.Because of its unique structural characteristics,the as-prepared LNCM material demonstrates excellent electrochemical properties in-cluding high rate capability and good cycleability when it is utilized as a cathode in the lithium ion battery(LIB).

Improving the intrinsic electronic conductivity of NiMo0_(4) anodes by phosphorous doping for high lithium storage

Heteroatom doping is one of the most promising strategies toward regulating intrinsically sluggish electronic conductivity and kinetic reaction of transition metal oxides for enhancing their lithium storage.Herein,we designed phosphorus-doped NiMo0_(4) nanorods(P-NiMo0_(4))by using a facile hydrothermal method and subsequent low-temperature phosphorization treatment.Phosphorus doping played an indispensable role in significantly improving electronic conductivity and the Li+diffusion kinetics of NiMo0_(4) materials.Experimental investigation and density functional theory calculation demonstrated that phosphorus doping can expand the interplanar spacing and alter electronic structures of NiMo0_(4) nanorods.Meanwhile,the introduced phosphorus dopant can generate some oxygen vacancies on the surface of NiMo0_(4),which can accelerate Li+diffusion kinetics and provide more active site for lithium storage.As excepted,P-NiMo0_(4) electrode delivered a high specific capacity(1,130 mA·g^(-1) at 100 mA·g^(-1) after 100 cycles),outstanding cycling durability(945 mA·g^(-1) at 500 mA·g^(-1) over 200 cycles),and impressive rate performance(640 mA·g^(-1)at 2,000mA·g^(-1))for lithium ion batteries(LIBs).This work could provide a potential strategy for improving intrinsic conductivity of transition metal oxides as high-performance anodes for LIBs.

Controllable synthesis of Li3PO4 hollow nanospheres for the preparation of high performance LiFePO4 cathode material

Lithium phosphate hollow nanospheres were prepared in a membrane dispersion microreactor using aqueous phosphoric acid and lithium hydroxide solutions as reactants. The influences of reactant flow rate ratio and temperature on the purity and morphology of the prepared nanospheres were investigated using X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The results showed that nanospheres prepared in the continuous flow condition had a hollow interior structure with high crystallinity. A possible mechanism for the formation of this hollow structured Li3 PO4 was also pro- posed. Using Li3 PO4 hollow nanospheres as the precursor, LiFePO4 hollow nanospheres were successfully synthesized via a solvothermal route in ethylene glycol. After coating with carbon, the LiFePO4/C hol- low nanospheres exhibited excellent electrochemical performance, especially at high rates, and could discharge124 mAh/g at 10 C, and even 98 mAh/g at 40 C.