Reaction Of KCl Research Articles

Potassium Chloride-Modified Urea Phosphate with Response Surface Optimization and Its Application Effect on Maize in Saline-Alkali Soil.

Urea phosphate (UP) is an acidic compound fertilizer, which significantly improves the low efficiency of P application caused by high pH in saline-alkali soil. In this study, urea phosphate potassium (UPK) was prepared by adding potassium chloride (KCl) to modify urea phosphate (UP) and the optimal combination of the synthetic process parameters was obtained using the response surface methodology at a four-variable, three-level experiment Box–Behnken design. Parameters such as the reaction temperature, KCl molar number, reaction time, and concentration of phosphoric acid were included for optimization. The thermostability, crystal structure, and microscopic morphology of UPK were measured by thermogravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscopy (SEM), respectively. The fertilizer efficiency was validated in an experiment on maize grown in pots containing saline-alkali soil. The highest K2O content and UPK yield were obtained by using the following parameters: reaction time of 60 min, KCl of 0.32 mol, reaction temperature of 78 °C, and phosphoric acid concentration of 70%. Under optimal conditions, the predicted K2O value content and UPK yield were 3.51% and 69.8%, respectively. The experimental K2O content and UPK yield were 3.42 ± 0.35% and 67.58 ± 1.25%, respectively, which confirmed the strength of the predicted model. This model can be used as an effective tool to predict the K2O content and yield in UPK. Characterizations showed that KCl was uniformly distributed in UPK and its fluidity was effectively improved as observed in the angle-of-repose results. Compared to a conventional phosphorus fertilizer diammonium phosphate (DAP), the yield, total P use efficiency, soil available phosphorus content, and soil acid phosphatase activity of UPK increased significantly by 25.58, 174.5, 24.41, and 41.25%, respectively, and the soil pH on UPK treatments decreased by 3.98% significantly. In conclusion, this novel technology to modify UP by using KCl has an enormous potential for large-scale applications to satisfy the increasing demand for UP fertilizers on saline-alkali soil.

Migration and speciation transformation of K and Cl caused by interaction of KCl with organics during devolatilization of KCl-loaded model biomass compounds

To better understand migration of K and Cl caused by interaction of KCl with organics, KCl-loaded model compounds (cellulose, xylan, lignin and pectin) were pyrolyzed within 300–800 °C using a fixed-bed apparatus. The amounts of different chemical occurrences of K and Cl in chars were quantitatively determined by sequential chemical fraction analysis combined with ICP-OES and IC. Morphologies and occurrence modes of Cl and K were further examined via XPS and SEM-EDS. Big differences in K and Cl migration were observed among four samples, and the distinction was closely related to types of organic functional groups. At temperature of below 500 °C, a low proportion of K was released from four samples, while amounts of water-soluble K was transformed into organically-bounded form via different ion-exchange reaction mechanisms, thereby promoting Cl release. About 46.93–53.31% and 32.47–41.75% of organic-K, presumably formed by reaction of KCl and methoxyls, were detected in lignin and pectin chars, apparently higher than that in xylan and cellulose chars. At the same time, amounts (71.98–81.83%) of Cl was released from doped pectin, followed sequentially by lignin (35.12–52.34%), cellulose (18.56–35.68%), and xylan (10.67–18.65%). Part of released Cl was recaptured by active carbon sites, thereby forming organochlorine, and C-Cl generation followed a sequence of lignin > xylan > cellulose > pectin. As pyrolysis proceeded, cellulose exhibited highest K release due to decomposition of organic-K, while a considerable of char-K with high thermal stability still retained in other samples. Mechanism on migration of K and Cl caused by reaction of KCl with organics was proposed.

Phase diagrams of the quinary system K+, NH4+, Mg2+// SO42−, Cl−- H2O at 273.15 K and 298.15 K and their application

Based on the requirement of the new technology for producing chloride-free potassium fertilizers by the reaction of KCl·MgCl2·6H2O and (NH4)2SO4, the phase equilibrium of the mutual quinary system K+, NH4+, Mg2+//SO42−, Cl−- H2O at 273.15 K and 298.15 K were studied using the isothermal dissolution equilibrium method under atmospheric pressure, and the corresponding phase diagrams were plotted. According to the diagrams, there are seven saturation points and eight solid phase crystalline fields. Fields of K2SO4·MgSO4·6H2O and (NH4u,K1-u)2SO4·MgSO4·6H2O are larger than other crystalline fields, which indicates that these two salts can crystallize out from solution easily. By analyzing and calculating the phase diagrams at 273.15 K and 298.15 K, chloride-free compound fertilizers can be produced via KCl·MgCl2·6H2O and (NH4)2SO4 as raw materials, and the by-product NH4Cl can crystallize out.

Phase diagrams of the quaternary system K+, NH4+//Cl−, SO42−-H2O at 273.15 K and their application

In order to produce chloride-free K-N compound fertilizers by the reaction of KCl (carnallite) and (NH4)2SO4 as raw materials, the phase equilibrium of the mutual quaternary system K+, NH4+//Cl−, SO42−-H2O and its two ternary subsystems KCl-NH4Cl-H2O, K2SO4-(NH4)2SO4-H2O were measured by isothermal method at 273.15 K. And the corresponding phase diagrams were plotted and analysed. The equilibrium phase diagram of the quaternary system K+, NH4+//Cl−, SO42−-H2O shows that there is one saturation point and three solid phase fields of crystallization. Three fields of crystallization represent solid solution salts corresponding to (K1−t, (NH4)t)2SO4, (K1−m, (NH4)m)Cl and ((NH4)n, K1−n)Cl respectively. The phase analysis shows that field of (K1−t, (NH4)t)2SO4 is larger than other crystalline fields, and there is no crystalline field of pure potassium sulfate, which indicates that the K1-t, (NH4)t)2SO4 is easy to crystallize out from solution. By analysing and calculating the phase diagrams of K+, NH4+//Cl−, SO42−-H2O at 273.15 K and 323.15 K, chloride-free K-N compound fertilizers (K1−t, (NH4)t)2SO4) can be obtained using KCl and (NH4)2SO4 as raw materials at 273.15 K, and ((NH4)t, K1−t)Cl can crystallize out at 323.15 K. The new technology shows the advantages of effective utilization of carnallite resources. The research on this quaternary phase diagram is the foundation of the chloride-free potash production by the reaction of carnallite and ammonium sulfate.

Analysis and Prediction of Corrosion of Refractory Materials by Potassium during Biomass Combustion-Thermodynamic Study.

As a kind of renewable resource, biomass has been used more and more widely, but the potassium contained in biomass can cause corrosion of the refractory. For a better understanding of corrosion thermodynamic mechanisms, the five components of common refractory materials (magnesium chrome spinel MgO·Cr2O3, magnesium aluminum spinel MgO·Al2O3, Al2O3, MgO, and Cr2O3) with potassium salts (K2CO3, K2SO4, and KCl) under high-temperature were studied by using the FactSageTM 7.0 software. Thermodynamic calculation results indicate that MgO is the best corrosion resistance of the five components of refractory materials. Based on the obtained results, the corrosion experiments in the laboratory were carried out (muffle furnace or high-temperature tube furnace) for corrosion reaction of KCl and MgO. The chemical compositions of the corroded samples were analyzed by X-ray diffraction (XRD). Under laboratory conditions (600–1200 °C), no corrosion products have been observed in the high-temperature corrosion experiments. The result indicates that to prevent the corrosion processes, refractories should contain as much MgO as possible.

Release and transformation of K and Cl during the pyrolysis of KCl-loaded cellulose

The migration of K and Cl during biomass thermal utilization can cause serious ash-related problems. Pyrolysis experiments with KCl-loaded cellulose were conducted in a fixed-bed reactor to investigate the reaction of KCl with organic functional groups. The migration pathways of K and Cl were obtained based on the analysis of char samples after pyrolysis. Results showed that the amounts of generated K2CO3 were negligible after pyrolysis at both temperature levels. After pyrolysis at 500 °C, char-Cl and char-K were generated, and the unreacted KCl existed in char as crystal particles. The released Cl amount increased first and then remained stable, whereas the Cl release ratio decreased monotonously with KCl content. Meanwhile, a small fraction of organic K was released. At 900 °C, almost all of the Cl (including KCl and char-Cl) was released, whereas a significant amount of char-K remained in char. Similar to the trend of O content, the amount of char-K increased first and then reached near-saturation with the increase in KCl content, indicating that char-K is associated with the char matrix via O. At 500 °C, during pyrolysis of cellulose with low KCl content, the formation of char-K and the release of Cl are the dominant migration pathways of K and Cl, respectively. With the increase in KCl content, unreacted KCl became the main existing form of K and Cl. The amounts of formed char-K and released Cl, as well as the formation ratio of char-Cl increased first and then reached saturation gradually.

Recent results from strangeness in transport models

In these proceedings we discuss recent developments in the microscopic description of strange particle production in nuclear collisions. We put a special emphasis on the production of hypernuclei at the upcoming FAIR and NICA facilities as well as the deep sub threshold, ϕ and Ξ- production yields measured with the HADES experiment. Employing new resonance decay channels we obtain a satisfactory description of ϕ and Ξ- production in deep sub threshold Ar+KCl reactions. Our results implicate that no new medium effects are required to describe the rare strange particle production data from low energy nuclear collisions.

Sub-threshold ϕ and production by high mass resonances with UrQMD

We present a possible explanation for the deep sub-threshold, ϕ and production yields measured with the HADES experiment in Ar+KCl reactions at A GeV and present predictions for Au+Au reactions at A GeV. To explain the surprisingly high yields of ϕ and hadrons we propose new decay channels for high mass baryon resonances. These new decay channels are constrained by elementary cross sections, and production in p+Nb. Based on the fits to the elementary reactions one obtains a satisfactorily description of ϕ and production in deep sub-threshold Ar+KCl reactions as well as the observed nuclear transparency ratio in proton-induced ϕ production in cold nuclear matter. The results implicate that no new medium effects are required to describe the rare strange particle production data in low energy nuclear collisions.

Dilepton production and reaction dynamics in heavy-ion collisions at SIS energies from coarse-grained transport simulations

Dilepton invariant-mass spectra for heavy-ion collisions at SIS 18 and BEVALAC energies are calculated using a coarse-grained time evolution from the Ultra-relativistic Quantum Molecular Dynamics (UrQMD) model. The coarse-graining of the microscopic simulations enables to calculate thermal dilepton emission rates by application of in-medium spectral functions from equilibrium quantum-field theoretical calculations. The results show that extremely high baryon chemical potentials dominate the evolution of the created hot and dense fireball. Consequently, a significant modification of the $\rho$ spectral shape becomes visible in the dilepton invariant-mass spectrum, resulting in an enhancement in the low-mass region $M_{ee} = 200$ to 600 MeV/$c^{2}$. This enhancement, mainly caused by baryonic effects on the $\rho$ spectral shape, can fully describe the experimentally observed excess above the hadronic cocktail contributions in Ar+KCl ($E_{\mathrm{lab}}=1.76$ $A$GeV) reactions as measured by the HADES collaboration and also gives a good explanation of the older DLS Ca+Ca ($E_{\mathrm{lab}}=1.04$ $A$GeV) data. For the larger Au+Au ($E_{\mathrm{lab}}=1.23$ $A$GeV) system, we predict an even stronger excess from our calculations. A systematic comparison of the results for different system sizes from C+C to Au+Au shows that the thermal dilepton yield increases stronger ($\propto A^{4/3}$) than the hadronic background contributions, which scale with $A$, due to its sensitivity on the time evolution of the reaction. We stress that the findings of the present work are consistent with our previous coarse-graining results for the NA60 measurements at top SPS energy. We argue that it is possible to describe the dilepton results from SIS 18 up to SPS energies by considering the modifications of the $\rho$ spectral function inside a hot and dense medium within the same model.

Thermal decomposition mechanism of ammonium nitrate and potassium chloride mixtures

The thermal decomposition of ammonium nitrate (AN) and potassium chloride (KCl) mixtures was investigated. The thermal properties were studied using differential scanning calorimetry (DSC), and the evolved gas was analyzed using thermogravimetry with mass spectrometry and pressurized DSC coupled with mass spectrometry (TG–DTA–MS and PDSC–MS). DSC measurements of AN/KCl mixtures in sealed and sealed-separated sample pans showed a sharp exothermic decomposition and lower onset temperature than pure AN, whereas AN/KCl in an open pan exhibited an endothermic reaction. In the sealed-separated pan, a separator with a pinhole divided the KCl and AN physically and the evolved gas could interact with both AN and KCl. TG–DTA–MS results revealed that HCl gas was evolved from AN/KCl, which indicated that the reaction of KCl with HNO3 dissociated from AN formed HCl, and subsequent destabilization of AN. However, the TG–DTA–MS results did not indicate the violent exothermic reaction due to using an open pan and ordinary pressure conditions. PDSC–MS was used to observe two exothermic reactions of AN/KCl and analyze the evolved gases from the reactions. A violent first exothermic reaction was accompanied by a large amount of N2 and N2O gases without H2O, and a second exothermic reaction accompanied by H2O, N2O, and other gases occurred subsequently. The reactions are $$ {\text{HCl }} + {\text{HNO}}_{ 3} \to {\text{NO}}_{ 2} {\text{Cl }} + {\text{H}}_{ 2} {\text{O }} \to {\text{Cl }} + {\text{NO}}_{ 2} + {\text{H}}_{ 2} {\text{O}} $$ , which have a lower energy barrier by 103 kJ mol−1 than the energy barrier that is needed for HNO3 homolysis cleavage, which is triggered by pure AN decomposition, $$ {\text{HNO}}_{ 3} \to {\text{OH}} + {\text{NO}}_{ 2} $$ . We therefore concluded that AN reacts with KCl to produce Cl radicals via HCl and NO2Cl, and the Cl radical triggers a radical chain reaction of AN.

Influence of Potassium Chloride on the Thermal Decomposition of Ammonium Nitrate

The thermal decomposition of ammonium nitrate (AN), activated carbon (AC), and potassium chloride (KCl) mixtures are investigated. The thermal properties were studied using differential scanning calorimetry (DSC) and the evolved gas was analyzed using thermogravimetry with mass spectroscopy (TG-DTA-MS). The time to maximum rate (TMRad) was then calculated using commercial thermal analysis software. DSC measurements of an AN/KCl mixture in a sealed sample pan showed a sharp exothermic decomposition and lower onset temperature than pure AN, whereas AN/KCl in an open pan exhibited an endothermic reaction. A mixture of AN/AC/KCl exhibited a lower onset temperature than both AN/AC and AN/KCl. TG-DTA-MS results revealed HCl gas was evolved from AN/KCl, which indicated the reaction of KCl with HNO3 dissociated from AN to form HCl, and the subsequent destabilization of AN and AN/AC by HCl. TMRad calculations showed that AN/KCl underwent a run-away reaction within one day under closed adiabatic conditions above 180°C.

In Situ ESEM Investigation of KCl-Induced Corrosion of a FeCrAl and a Model FeNiCrAl Alloy in Lab Air at 450°C

The very early stages of KCl-induced corrosion of a FeCrAl and a FeNiCrAl alloy in an O2/H2O environment were studied using in-situ Environmental Scanning Electron Microscopy (ESEM). The samples were KCl contaminated and then exposed to lab air at a total pressure of 4.8 Torr at 450°C. After exposure, the samples were analyzed using SEM-EDX, FIB and STEM-EDX. For both alloys, fast oxide growth occurred at the KCl particles. Far away from the KCl particles, a thin base oxide formed with potassium chromate nodules on top. The base oxide was layered, consisting of iron-chromium oxide on top and alumina in the bottom part. The FeCrAl alloy suffered internal oxidation while the FeNiCrAl did not. Both alloys formed sub-scale chlorides. A mechanism is proposed for the reaction of KCl on the surface and for the formation of different surface features at the KCl particles.

Searching a dark photon with HADES

We present a search for the e+e− decay of a hypothetical dark photon, also named U vector boson, in inclusive dielectron spectra measured by HADES in the p(3.5 GeV) + p, Nb reactions, as well as the Ar (1.756 GeV/u) + KCl reaction. An upper limit on the kinetic mixing parameter squared ϵ2 at 90% CL has been obtained for the mass range MU=0.02–0.55 GeV/c2 and is compared with the present world data set. For masses 0.03–0.1 GeV/c2, the limit has been lowered with respect to previous results, allowing now to exclude a large part of the parameter region favored by the muon g−2 anomaly. Furthermore, an improved upper limit on the branching ratio of 2.3×10−6 has been set on the helicity-suppressed direct decay of the eta meson, η→e+e−, at 90% CL.

Searching a dark photon with HADES

The existence of a photon-like massive particle, the γ ‘ or dark photon, is postulated in several extensions of the Standard Model to explain some recent puzzling astrophysical observations, as well as to solve the sofar unexplained deviation between the measured and calculated values of the muon anomaly. The dark photon, unlike the conventional photon, would have mass and would be detectable via its mixing with the latter. We present a search for the e + e − decay of such a hypothetical particle, also named U vector boson, in inclusive dielectron spectra measured by HADES in the p (3.5 GeV) +p, Nb reactions, as well as the Ar (1.756 GeV/u) + KCl reaction. An upper limit on the kinetic mixing parameter squared (ϵ 2 ) at 90% CL has been obtained for the mass range M(U)= 0.02 - 0.55 GeV/c 2 and is compared with the present world data set. Furthermore, an improved upper limit of 2.3 × 10−6 at 90% CL has been set on the branching ratio of the helicity-suppressed direct decay of the η meson η → e +e −.

ChemInform Abstract: K3B6O10Cl: A New Structure Analogous to Perovskite with a Large Second Harmonic Generation Response and Deep UV Absorption Edge.

AbstractSingle crystals of the title compound are prepared by reaction of KCl and H3BO3 in a KF/PbO flux (KF:KCl:PbO:H3BO3 = 2:1:2:6, Pt crucible, 650 °C, 15 h).

Probing dense nuclear matter with electromagnetic and rare hadronic probes

We present preliminary results on strangeness and dilepton production in Ar+KCl reactions at 1.76 AGeV. For the first time an ω signal could be extracted in heavy-ion collisions in this energy region. Furthermore we find a strong enhancement of yield in the low invariant lepton pair mass region over an elementary reference suggesting the onset of non trivial effects of the medium. This hint is supported by a nearly complete vanishing of the OZI suppression of the ϕ to ω ratio which is characteristic for elementary reactions.

A novel sandwich-type polyoxometalate compound with visible-light photocatalytic H2 evolution activity

A tin(II) tungstosilicate derivative K(11)H[Sn(4)(SiW(9)O(34))(2)]·25H(2)O with four sandwiched Sn(2+) cations was prepared by reaction of SnCl(2), KCl and Na(10)[α-SiW(9)O(34)]·xH(2)O. Visible-light photocatalytic H(2) evolution activity was observed with Pt nanoparticles as co-catalyst and methanol as sacrificial agent.

In-medium effects onK0mesons in relativistic heavy-ion collisions

We present the transverse momentum spectra and rapidity distributions of $\pi^{-}$ and K$^0_S$ in Ar+KCl reactions at a beam kinetic energy of 1.756 A GeV measured with the spectrometer HADES. The reconstructed K$^0_S$ sample is characterized by good event statistics for a wide range in momentum and rapidity. We compare the experimental $\pi^{-}$ and K$^0_S$ distributions to predictions by the IQMD model. The model calculations show that K$^0_S$ at low tranverse momenta constitute a particularly well suited tool to investigate the kaon in-medium potential. Our K$^0_S$ data suggest a strong repulsive in-medium K$^0$ potential of about 40 MeV strength.

KCl-Induced Corrosion of a 304-type Austenitic Stainless Steel in O2 and in O2 + H2O Environment: The Influence of Temperature

The oxidation of the 304-type (Fe18Cr10Ni) austenitic stainless steel was investigated in the temperature range 400–600 °C in 5% O2 and 5% O2 + 40% H2O. Exposure time was up to 1 week. Prior to exposure, the polished samples were coated with 0.1 mg/cm2 KCl. Uncoated samples were also exposed and used as references. The oxidized samples were analyzed by gravimetry and by ESEM/EDX, XRD, IC and AES. The results show that KCl is strongly corrosive. Corrosion is initiated by the reaction of KCl with the chromia-containing oxide that normally forms a protective layer on the alloy. This reaction produces potassium chromate particles, leaving a chromium-depleted oxide on the alloy surface. At 500 and 600 °C this results in rapid oxidation, resulting in the formation of a thick scale consisting of a mixture of hematite, spinel oxide ((Fe,Cr,Ni)3O4) and K2CrO4. The thick scale is poorly protective and permeable to e.g. chloride ions. The KCl-induced corrosion of alloy 304L in dry O2 and in an O2 + H2O mixture increases strongly with temperature in the range 400–600 °C. The strong temperature dependence is explained partly by the temperature dependence of the chromate-formation reaction and partly by the ability of the chromium-depleted oxide to protect the alloy at low temperature. At 400 °C, the oxide was still protective after 168 h.

The Influence of Small Amounts of KCl(s) on the Initial Stages of the Corrosion of Alloy Sanicro 28 at 600 °C

The influence of KCl(s) on the oxidation of Sanicro 28 (35Fe27Cr31Ni) austenitic stainless steel at 600 °C in 5% O2 + 40% H2O and in 5% O2 was investigated. The samples were coated with 0.1 mg/cm2 KCl(s) prior to exposure. The exposure time was 1, 24, 72 and 168 h. Uncoated samples were exposed for reference. The oxidized samples were analyzed by SEM/energy-dispersive X-ray (EDX), X-ray diffraction (XRD), and AES. The amount of chloride and chromate on the samples was analyzed quantitatively by ion chromatography after exposure. KCl(s) is very corrosive towards Sanicro 28. Corrosion is initiated by the formation of potassium chromate through the reaction of KCl(s) with the protective oxide, chloride leaving the sample in the form of HCl. Chromate formation is a sink for chromium in the oxide and leads to a deterioration of its protective properties. In the 5% O2 + 40% H2O environment, there is a stoichiometric relationship between the chromate formed and the chloride consumed. In dry O2 chromate formation is relatively slow, leaving more unreacted KCl(s) on the surface than in 5% O2 + 40% H2O. Once the protective, chromium-rich oxide has been depleted in chromium by chromate formation, the alloy becomes susceptible to direct attack by the remaining KCl(s).