检索结果-南通市图书馆

Decomposition behavior of CaSO_4 during potassium extraction from a potash feldspar-CaSO_4 binary system by calcination

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2018年第4期26卷 838-844页

作者： li lü Chun li Guoquan Zhang Xiaowei Hu Bin liang School of Chemical Engineering Sichuan University

The extraction of potassium from a tablet mixture of K-feldspar ore and CaSO4by roasting was studied with a focus on the effects of the decomposition behavior of CaSO4on the potassium extraction *** roasted slags were characterized by X-ray diffraction（XRD）,scanning electron microscopy（SEM）,energy-dispersive X-ray spectroscopy,and thermogravimetric（TG）*** XRD analysis revealed that hydrosoluble mischcrystal K2Ca2（SO4）3was obtained by ion exchange of Ca^2＋ in CaSO4 and K^＋ in ***,the intermediate product,SiO2,separated from KAl Si3O8and reacted with CaSO4to decompose *** SEM results showed that some blowholes emerged on the surface of the CaSO4particles when they reacted with SiO2at 1200℃,which indicates that SO2and O2gases were released from *** TG curves displayed that pure CaSO4could not be decomposed below 1200℃,while the mixture of K-feldspar ore and CaSO4began to lose weight at 1000℃.The extraction rate of potassium and decomposition rate of CaSO4were 62%and 44%,respectively,at a mass ratio of CaSO4to K-feldspar ore of 3：1,temperature of 1200℃,tablet-forming pressure of6 MPa,and roasting time of 2 *** decomposition of CaSO4reduced the potassium extraction rate;therefore,the required amount of CaSO4was more than the theoretical ***,excess CaSO4was also undesirable for the potassium extraction reaction because a massive amount of SO2and O2gas were derived from the decomposition of CaSO4,which provided poor contact between the *** SO2released from CaSO4decomposition can be effectively recycled.

关键词： K-feldspar Calcium sulfate Potassium extraction Calcium sulfate decomposition Roasting

The equation of chronoamperometric current on an oblate hemispheroid microelectrode and its verification

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 1996年第4期14卷 331-337页

作者： Diao, GW li, l Zhang, ZX NANJING UNIV DEPT CHEMNANJING 210093JIANGSUPEOPLES R CHINA

With the aspect of equivalent diffusion layer an analytical chronoamperometric current equation on an oblate hemispheroid microelectrode for reversible electrochemical condition is derived. To verify this equation the chronoammograms have been obtained with benzoquinone in McIlvaine buffer solution (pH 7.0) at a mercury oblate hemispheroid microelectrode. The experimental results agree with the theoretical conclusions.

关键词： chronoamperometric current equation oblate hemispheroid microelectrode reduction of benzoquinone

Thermodynamic Calculation of Segregation in Multicomponent Steels

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 1996年第3期12卷 238-240页

作者： li, l Delaey, l Wollants, P Biest, VD KATHOliEKE UNIV lEUVEN DEPT MTMB-3001 HEVERLEEBELGIUM

The thermodynamic equation for segregation in multicomponent steels is extended from that in ternary system and the segregation amounts of Cr, C and P in the intergranular phase in a Cr-steel are estimated.

关键词： Cr Thermodynamic Calculation of Segregation in Multicomponent Steels

Study on reactions of gaseous P_2O_5 with Ca_3(PO_4)_2 and SiO_2 during a rotary kiln process for phosphoric acid production

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2018年第4期26卷 795-805页

作者： Qiang liu Weizao liu li lü Ruhu li Bin liang Hairong Yue Shengwei Tang Chun li College of Chemical Engineering Sichuan University

In a rotary kiln process for phosphoric acid production,the reaction between gaseous phosphorus pentoxide（P2O5）and phosphate ore and silica contained in feed balls（the so-called P2O5＂absorption＂）not only reduces phosphorous recovery but also generates a large amount of low melting-point side *** products may give rise to formation of kiln ring,which interferes with kiln operation *** this study,the reactions of gaseous P2O5with solid calcium phosphate（Ca3（PO4）2）,silica（SiO2）and their mixture,respectively,were investigated via combined chemical analysis and various characterizations comprised of X-ray diffraction（XRD）,Fourier-transform infrared（FT-IR）spectroscopy,thermogravimetric analysis and differential scanning calorimeter（TG＆DSC）,and scanning electron microscopy and energy dispersive spectrometer（SEM＆EDS）.Attentions were focused on apparent morphology,phase transformation and thermal stability of the products of the P2O5＂absorption＂at different *** results show that the temperature significantly affected the＂absorption＂.The reaction between pure Ca3（PO4）2 and P2O5 occurred at 500℃.Calcium metaphosphate（Ca（PO3）2）was the primary product at the temperatures≤900℃ with its melting point≤900℃ while calcium pyrophosphate（Ca2P2O7）was obtained over 1000℃,which has a melting point≤1200℃.The＂absorption＂by pure SiO2 started at 800℃ and the most significant reaction occurred at 1000℃ with formation of silicon pyrophosphate（SiP2O7）product of melting point≤1000℃.Using mixed Ca3（PO4）2and SiO2as raw material,the＂absorption＂by Ca3（PO4）2 was enhanced due to existence of *** 600–700℃,silica was inert to P2O5and thus formed a porous structure in the raw material,which accelerated diffusion of gaseous P2O5inside the *** higher temperatures,the combined＂absorption＂by calcium phosphate and reaction between silicon dioxide and the＂absorption＂product calcium pyrophosphate,reinforced the＂absorption＂by the ***,it was found that both

关键词： Kiln phosphoric acid Kiln ring Absorption Calcium metaphosphate Calcium pyrophosphate Back reaction

CT arterial portography and CT hepatic arteriography in detection of micro liver cancer

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 1999年第3期5卷 225-227页

作者： li l Wu PH Mo YX lin HG Zheng l li JQ lu lX Ruan CM Chen l Sun Yat Sen Univ Med Sci Ctr Canc Dept Imaging & Intervent Radiol Guangzhou 510060 Guangzdong Prov Peoples R China

AIM To recognize the characteristic findings of micrQliver cancer (MlC) and to evaluate the effect of CT arterial portography (CTAP) and CT hepatic arteriography (CTHA) in diagnosis of MlC. METHODS Between April 1996 to December 1998, CTAP and CTHA were performed in 12patients with MlC, which were not detect ed byconventional CT examinations. After CTHA, 3 ml-- 5 ml mixture of lipiodol, doxorubic in andmitomycin C were injected into hepatic arterythrough the catheter, and then followed up by CTthree or four weeks later (lipiodol CT lP-CT).RESUlTS A total of 22 micro--tumors (0 .2 cm 0.6 cm in diameter ) were detected in 12patients, which manifested as small perfusiondefects in CTAP and small round enhancement inCTHA. The rate of detectability of CTAP andCTHA was 68.2% (15/ 22) and 77.3% (17/ 22)respectively, and the rate of the simultaneoususe of both procedures reached 86. 4% (19/ 22 ).All micro--tumors were demonstrated as punctatelipiodol deposit fool in lP--CT. After lP--CT, theelevated serum level of Q-fetoprotein (AFP)dropped to the normal level in all *** The CTAP and CTHA are the mostsensitive imaging methods for detecting microIiver cancer. Confirmed by the change of theelevated serum AFP level and lipiodol depositfool in lP-CT, small perfusion defects in CTAPand punctate enhancement in CTHA may suggestmicro--liver cancer.

关键词： CT arterial portography and CT hepatic arteriography in detection of micro liver cancer

Diagnosis of bile duct hepatocellular carcinoma thrombus without obvious intrahepatic mass

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2010年第39期16卷 4998-5004页

作者： long XY li YX Wu W li l Cao J. Department of General Surgery Xiangya Hospital Central South University Changsha 410008 Hunan Province China. liyixiong6@***

AIM:To study the diagnosis of hepatocellular carcinoma(HCC)presenting as bile duct tumor thrombus with no detectable intrahepatic ***:Six patients with pathologically proven bile duct HCC thrombi but no intrahepatic mass demonstrated on the preoperative imaging or palpated intrahepatic mass during operative exploration,were *** clinical and imaging data were retrospectively *** major findings or signs on comprehensive imaging were correlated with the surgical and pathologic ***:Jaundice was the major clinical symptom of the *** elevated serum total bilirubin,direct bilirubin and alanine aminotransferase levels were in concordance with obstructive jaundice and the underlying liver *** the 6 patients showing evidence of viral hepatitis,5 were positive for serum alpha fetoprotein and carbohydrate antigen 19-9,and 1 was positive for serum carcinoembryonic *** patient was correctly diagnosed by *** main features of patients on comprehensive imaging were filling defects with cup-shaped ends of the bile duct,with large filling defects presenting as casting moulds in the expanded bile duct,hypervascular intraluminal nodules,debris or blood clots in the bile *** obvious circular thickening of the bile duct walls was ***:Even with no detectable intrahepatic tumor,bile duct HCC thrombus should be considered in patients predisposed to HCC,and some imaging signs are indicative of its diagnosis.

关键词： Hepatocellular carcinoma Obstructive jaundice Bile duct tumor thrombus Diagnosis Diagnostic imaging

Effect of two-step cooling process on mechanical properties of TRIP steel with high performance

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2018年第4期25卷 426-432页

作者： M.l. li H. Jiang Y.l. He l.B. Chen G.T. Zhang H. Wang X.G. lu l. li School of Materials Science and Engineering Shanghai University Shanghai 200072 China State Key laboratory of Advanced Special Steel Shanghai University Shanghai 200072 China Pangang Group Research Institute Panzhihua 617000 Sichuan China

A novel two-step cooling experiment was established to simulate the slow cooling process of continuous annealing production line for transformation-induced plasticity （TRIP） steel. The microstructures and mechanical properties of TRIP steel soaked at 700℃ for different time were investigated by tensile test, scanning electron microscopy, X-ray diffraction, and thermodynamic and kinetic calculation. It is shown that the steel soaked for 15 s exhibits the optimal product of strength and elongation （PSE 〉 30,000 MPa%） due to the transformation of austenite to proeutectoid ferrite, which delays the bainite transformation and improves the stability of retained austenite. In addition, the mechanical properties of TRIP steel soaked over 30 s are much lower, resulting from the precipitation of cementite, which decreases the stability of retained austenite and weakens the TRIP effect.

关键词： Transformation induced plasticity steel Two-step cooling Microstructure Mechanical property

Preparation of synthetic rutile via selective sulfation of ilmenite with(NH4)2SO4 followed by targeted removal of impurities

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2017年第6期25卷 821-828页

作者： Weizao liu Xiaomei Wang Zhenpu lu Hairong Yue Bin liang li lü Chun li College of Chemical Engineering Sichuan University Chengdu 610065 Chino

This paper describes a novel, facile chemical pathway for preparing synthetic rutile from ilmenite. The pathway consists of two primary units, i.e., selectively sulfating ilmenite, which was realized via roasting ilmenite with(NH_4)_2SO_4followed by selective thermal decomposition of the sulfated ilmenite, and targeted leaching of the impurities. The effects of the process parameters were systematically investigated. The results showed that the optimum sulfation conditions were a mass ratio of(NH_4)_2SO_4to ilmenite of 14, temperature of 360 °C, and time of 120 min with a sulfation ratio of ~ 95%. The optimum thermal decomposition conditions were480 °C in N_2 atmosphere, and nearly all Ti OSO_4 were decomposed with co-decomposition of Fe SO_4 of 23%. For acid leaching, the optimum conditions were 2.5 wt% HCl, 98 °C and 120 min. Under those conditions, 94.2% iron was removed with a Ti O_2 dissolution loss b 1%. For alkali leaching, 67% Si O_2 was removed in 5 wt% Na OH at102 °C for 1 h. A synthetic rutile with a Ti O_2 content N 92 wt% and total Mg O + Ca O b 1.5 wt% was *** on these results, a schematic flowsheet was proposed. Additionally, it was found that the decomposition of Fe SO_4 mixed with Ti OSO_4 under N_2was inhibited due to its oxidation to a higher thermal stability Fe_2(SO_4)_3by oxygen emitted from the decomposition of Ti OSO_4. At the same time, Ti OSO_4 decomposition was promoted due to the immediate in situ consumption of oxygen by Fe SO_4. The synergetic effect might be responsible for the enhanced selectivity of sulfated ilmenite thermal decomposition.

关键词： Synthetic rutile Ilmenite Titania Ammonium sulfate Thermal decomposition

A NOVEl METHOD FOR EVAlUATING PlANE STRESS DYNAMIC FRACTURE TOUGHNESS OF 0Cr18Ni10Ti STAINlESS STEEl WElDED JOINTS

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English letters) 2008年第4期21卷 303-312页

作者： Z.J. Xu Y.l. li School of Aeronautics Northwestern Polytechnical University Xi＇an 710072 China

A novel method was proposed for the evaluation of Mode I dynamic fracture toughness （DFT） under plane stress and small scale yielding conditions for welded joints of stainless steel （SS）, 0Cr18Ni10Ti. In a hybrid experimental-numerical approach, the experiments were carried out on the Hopkinson pressure bar apparatus, and three dimensional （3D） transient numerical simulations were performed by a finite element （FE） computer program. Macroscopical plastic deformation was observed at the loading and supporting points, on the specimens, after the test, which could cause a large error if omitted in the numerical simulation. Therefore, elustic-viscoplustic analysis was performed on the specimen by adopting the Johnson-Cook （J-C） model to describe the rate-dependent plastic flow behavior of the material. The material heterogeneity in the mismatched welded joints, induced by the difference in the base metal （BM） and the weld metal （WM） in yield stress, has also been taken into consideration by using the J-C models separately. Good accordance was obtained between the experimental and the computational results by the present approach. The relationship between plane stress DFT and loading rate was also obtained on the order of 108 MPa.m^1/2.s^-1.

关键词： 0Cr18Ni10Ti Welded joint High strain rate Dynamic fracture Plane stress