Mechanisms for puffing inhibition of coal tar based needle coke with disodium hydrogen phosphate (DHP) and boric acid

The capacity of 10%, 30%, and 50% ammonium dihydrogen phosphate were replaced with an equal amount of three phosphate (potassium dihydrogen phosphate, sodium dihydrogen phosphate, disodium hydrogen phosphate) respectively. Magnesium phosphate cement was made by phosphate of replaced, which strength, setting time, fluidity, hydration temperature, and the hydration products was researched. The results show that: MPC was made that replaced with the equal amount of three kind of phosphate, which has good mechanical properties. Setting time and fluidity change along with the replacment. Three kind of phosphate replace ammonium dihydrogen phosphate, which change the hydration process of MPC. When ammonium dihydrogen phosphate was replaced by an equal amount of disodium hydrogen phosphate, the temperature of hydration is only 69.4 °C. XRD showed that the diffraction peaks of composite’s magnesium phosphate cement increases.

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XRD Characterization of the Structure of Graphites and Carbon Materials Obtained by the Low-Temperature Graphitization of Coal Tar Pitch

Eurasian Chemico-Technological Journal ◽

10.18321/ectj198 ◽

2015 ◽

Vol 17 (2) ◽

pp. 87 ◽

Cited By ~ 20

Author(s):

Ch.N. Barnakov ◽

G.P. Khokhlova ◽

A.N. Popova ◽

S.A. Sozinov ◽

Z.R. Ismagilov

Keyword(s):

Low Temperature ◽

Carbon Materials ◽

Coal Tar ◽

Structural Phase ◽

Coherent Scattering ◽

Amorphous Structure ◽

Coal Tar Pitch ◽

X Ray Diffraction ◽

Needle Coke ◽

The Individual

The structure of some commercial graphites and carbon materials (CMs) obtained by the low-temperature catalytic graphitization of coal tar pitch with iron salt, needle coke, foamed graphite as the catalysts has been studied. The study was performed using the X-ray diffraction technique with reflections from base plane and their decomposition into two components corresponding to the structural phases of graphite which have different XRD characteristics. Various CMs were compared with respect to the structural phase ratio, distance between polyarene layers in these phases, and sizes of the coherent scattering regions. The (004) reflection provided a better fit of some properties of graphites to the calculated XRD characteristics as compared to calculation from the (002) reflection. In the case of carbonization of coal tar pitch with investigated catalyst additions, prepared carbon materials have a higher degree of graphitization and a crystallite size greater than in the other case of carbonization of the individual pitch. The highest catalytic activity is shown by foamed graphite. It was found that the use of foamed graphite as the catalyst at 800-900 ºC produced carbon materials possessing a crystalline structure with interplanar spacing close to that in commercial graphites, while in the absence of catalyst the coal tar pitch material has an amorphous structure.

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