Influence Of Na2CO3 Research Articles

Influence of Na2CO3 on the activation degree and microstructure of coal gasification coarse slag

ABSTRACT Silicon in coal gasification coarse slag (CGCS) accounts for more than 40%. CGCS can be developed into an inorganic silicon source to improve its utilization value. Alkali activation can increase extraction rate of silicon. In this study, the influence of Na2CO3 on the activation degree and microstructure of CGCS was investigated. The activation mechanism was discussed based on IR, XRD, SEM, and EDS data. The results showed that the dosage of Na2CO3 was positively correlated with SiO2/Al2O3 in CGCS, which is generally 0.8 ~ 1.3 times of CGCS. The activation temperature of CGCS was 800°C ~ 850°C. A small amount of residual carbon could slightly reduce the activation temperature. The alkali activation process involved depolymerizing the polymer structure into an oligomer, whereby the crystalline structure was transformed into an amorphous structure. Moreover, Q4 structure in CGCS could be more easily activated than Q3 or Q2 structure. The activation reaction was carried out under gas-liquid-solid three-phase conditions. The diffusion effect of CO2 gas could be fully utilized in the activation process to ensure the melting of heteroatoms and the formation of defects, which prevented the emergence of crystalline substances. This research provides a solid theoretical foundation for low-cost and high-quality extraction of silicon from CGCS.

Influence of Na2CO3 on combustion performance of civil clean coke

Civil clean coke is a low-pollutanted civil clean fuel made of coal and multi-functional composite additives by high-temperature carbonization, which is of positive significance to solve the problem of air pollution caused by civil bulk combustion. However, problems such as high ignition temperature and poor combustion performance exist in the use of civil clean coke in the early stage. In this paper, Lvliang fat coal is taken as the research object. Coke samples are prepared by adding different additives and high-temperature carbonization. The influence of Na2CO3 on the combustion performance of civil clean coke is analyzed by TG-DTG, BET, thermodynamics kinetics and other methods. The results show that the civil clean coke prepared by high temperature dry distillation with 1.0% Na2CO3 added, the ignition temperature by impregnation method is 53 K lower than that of coke without additives; after adding Na2CO3, the TG and DTG curves of coke shifted significantly to the left, the average combustion rate increased from 0.38 mg/min to 0.75 mg/min, and the comprehensive combustion index increased from 2.01 × 10-10 mg2 /(min2 ·K3 ) to 11.14 × 10-10 mg2 /(min2 ·K3 ); after adding Na2CO3, the specific surface area of coke is significantly increased and the pore structure is more developed, which promotes the oxygen transfer in the combustion process and significantly reduces the apparent activation energy of the combustion system. The apparent activation energy in the low temperature zone is reduced from 454.28 kJ/mol to 306.85 kJ/mol, and the apparent activation energy in the high temperature zone is reduced from 557.36 kJ/mol to 95.36 kJ/mol. The combustion performance of civil clean coke is improved.

Influence of Na2CO3 and K2CO3 Addition on Iron Grain Growth during Carbothermic Reduction of Red Mud

Red mud is a by-product of alumina production from bauxite ore by the Bayer method, which contains considerable amounts of valuable components such as iron, aluminum, titanium, and scandium. In this study, an approach was applied to extract iron, i.e., carbothermic reduction roasting of red mud with sodium and potassium carbonates followed by magnetic separation. The thermodynamic analysis of iron and iron-free components’ behavior during carbothermic reduction was carried out by HSC Chemistry 9.98 (Outotec, Pori, Finland) and FactSage 7.1 (Thermfact, Montreal, Canada; GTT-Technologies, Herzogenrath, Germany) software. The effects of the alkaline carbonates’ addition, as well as duration and temperature of roasting on the iron metallization degree, iron grains’ size, and magnetic separation process were investigated experimentally. The best conditions for the reduction roasting were found to be as follows: 22.01% of K2CO3 addition, 1250 °C, and 180 min of duration. As a generalization of the obtained data, the mechanism of alkaline carbonates’ influence on iron grain growth was proposed.

Influence of Na2CO3 and CaCO3 additions on the aluminate slag formation during a single-stage reducing roasting of red mud

Influence of Na2CO3 and CaCO3 additions on the aluminate slag formation during a single-stage reducing roasting of red mud

Solvent-free synthesis of nano-cancrinite from rice husk ash

The solvent used in the hydrothermal synthesis of zeolites is a major obstacle to achieve green and sustainable methods of synthesis, so the development of environmentally friendly zeolite synthesis technology has aroused widespread concern. As a solid waste, it still has a challenge for zeolites synthesis from rice husk ash by solvent-free method to increase its recovery rate and economic value. Our approach focused on reutilization of rice husk ash by converting it to cancrinite without employing solvents. The raw and as-synthesized products were characterized by XRD, XRF, SEM, FT-IR, UV-Raman, and BET analysis. The influence of Na2CO3·10H2O/SiO2 molar ratio and synthesis time on cancrinite crystal growth and properties was evaluated by various analytical methods. The results suggested that the optimal conditions of Na2CO3·10H2O/SiO2 and synthesis time for the cancrinite synthesis were 0.3 and 72 h, at this condition, the size of cancrinite was about 200 nm, the BET surface area was estimated to 59.909 m2/g, and the external surface area was 55.456 m2/g, which indicate the cancrinite was a good mesoporous material. From this study, it could be known that the synthesis process of cancrinite by solvent-free route was an amorphous sodium aluminosilicate phase followed by sodalite and finally cancrinite, which is different from the traditional hydrothermal method.

Effects of Sodium Carbonate Additive on the Hydroliquefaction of a Sub-bituminous Coal with Fe-Based Catalyst under Mild Conditions

In this paper, the influence of Na2CO3 (NC) on the hydroliquefaction performances of Hongliulin (HLL) coal with an Fe-based catalyst, γ-FeOOH (FC), under mild conditions was investigated, and the properties of the resulting preasphaltene and asphaltene were examined. Results show that the addition of NC to FC-catalyzed liquefaction significantly promoted coal conversion and oil production and reduced water production under mild conditions, especially at high initial H2 pressure. The H2 consumption of mild liquefaction (0.53–1.93%) is much smaller than that of the traditional liquefaction processes, and the addition of NC to FC can enhance H2 consumption, especially the runs with weak hydrogen donor solvents. The addition order of NC and FC is an important factor which can affect the activity of FC and NC binary catalysts. There exists a prominent synergistic effect between NC and FC in HLL coal hydroliquefaction, and the synergistic effect could be ascribed to the combined promotion actions of NC for the ...

Influence of Na2CO3 as Additive on Direct Reduction of Boron-bearing Magnetite Concentrate

Boron-bearing magnetite concentrate is typically characterized by low grade of iron and boron (wTFc = 51 %— 54 %, wB2O3 = 6 % — 8%), as well as the close intergrowth of ascharite phase and magnetite phase. A promising technology was proposed to separate iron and boron by coupling the direct reduction of iron oxides and Na activation of boron minerals together. The influence of Na2CO3 as additive on the direct reduction of boron-bearing magnetite was studied by chemical analysis, kinetic analysis, XRD analysis and SEM analysis. The results showed that the addition of Na2CO3 not only activated boron minerals, but also reduced the activation energy of the reaction and promoted the reduction of iron oxides. Besides, the addition of Na2CO3 changed the composition and melting point of non-ferrous phase, and then promoted the growth and aggregation of iron grains, which was conducive to the subsequent magnetic separation. Thus, the coupling of the two processes is advantageous.

Influence of Na2CO3 on structure and electrochemical properties of nanometre Co substituted nickel hydroxide

Co substituted nanonickel hydroxide, which used NiCl2 and Na2CO3 as nickel source and buffer respectively, was synthesised by ultrasonic method. XRD, TEM, PSD and EDS were used to characterise the physical and electrochemical performance of the prepared samples respectively. The electrochemical performance affected by Co substituted ratio and buffer content were determined by cyclic voltammogram and discharge–charge test. The results demonstrated that the Co substituted nanonickel hydroxide was the mixed phase of α- and β-Ni(OH)2 and the increasing Co content led to the larger proportion of α-nickel hydroxide. An increase in Na2CO3 content was beneficial to form α-nickel hydroxide. The morphology of all samples was the needle-like and the length/diameter ratio decreased with increasing Na2CO3 content. Composite electrodes were made by mixing 8 wt-% nickel hydroxide with commercial β-nickel hydroxide. The discharge capacities of electrodes first increased and then decreased with the change of Na2CO3 content. When Ni2+ was 0·4 mol L−1 and Na2CO3 was 0·5 g, the electrode had the maximum discharge capacity, which reached 306·9 mAh g−1 at 0·5 C discharge/charge rate.