Increasing the resistance of lances immersed in liquid metal in iron desulfurizing departments

Conclusions We developed, perfected, and introduced in industrial conditions the process of manufacturing wear-resistance carbon-containing bodies, and a slaking slip containing kaolin and a water solution of orthophosphoric acid.The exploitation of immersion lances lined with the new composition made it possible, compared with previously used linings, in the conditions of the Azovstal' combine to boost their life on average from 121 to 507 blows per annum, and to reduce the consumption of refractory body from 12 to 7 tons per lance.Translated from Ogneupory, No. 8, pp. 47–50, August, 1984.     

Scrap cast iron and copper‐modified cast iron for reductive degradation of 2,4‐dinitrotoluene

BACKGROUND: Little attention has been paid to the use of large‐sized scrap cast iron for reduction of refractory organic pollutants at neutral pH and in the presence of dissolved oxygen (DO). RESULTS: Scrap cast iron and copper‐modified cast iron with fresh surfaces have a high reactivity towards the reduction of 2,4‐dinitrotoluene (2,4‐DNT). The extent of conversion reached around 80% and 97% respectively, though it gradually decreased with repeated reactions to relatively stable values of 63% and 72%, and recovered once the reacted filings were cleaned by dilute acid. After 50 days reaction, no dissolved copper appeared in the copper‐modified cast iron process. The mass loss of copper due to physical detachment reached 1.1% of the total coated copper within the initial 20 reaction days, and only 0.3% appeared in the next 30 days. 2,4‐DNT oxidizes scrap cast iron to generate mainly FeFe₂O₄ with DO, however, it oxidizes scrap copper‐modified cast iron to generate mainly γ‐FeO(OH) and α‐FeO(OH). CONCLUSION: Both samples of cast iron were successfully applied in the treatment of neutral wastewater containing 2,4‐DNT with high reactivity and good repeatable efficiency. Electrode reaction rate was enhanced by the deposited copper, which has strong chemical and physical stability. Copyright © 2011 Society of Chemical Industry     

Boride-based coatings for protection of cast iron against wear

The components made of cast irons require protection against wear in severe service conditions. Surface engineering can be used to prevent mechanical failures of cast iron components due to excessive friction-related wear. The iron boride-based coatings can be applied on the entire working surfaces of large-size complex shape cast iron components through the thermal diffusion process. Tribological properties of these coatings obtained have been studied using the pin-on-disc test configuration in simulating application conditions. The obtained iron boride coatings demonstrated significantly lower wear losses compared to bare cast iron, stable behaviour of coefficient of friction during time and no structural degradation and spalling. The superior wear resistance of boride-based coatings on cast iron is dealt with the combination of their high hardness, specific ‘sawtooth’ double-layer morphology obtained through the thermal diffusion process, diffusion-related bonding to the substrate, self-lubricating thin ‘tribo-film’ formed during friction and high thermal and chemical stability.     

Auto-analysis system for graphite morphology of grey cast iron

The current method to classify graphite morphology types of grey cast iron is based on traditional subjective observation, and it cannot be used for quantitative analysis. Since microstructures have a great effect on the mechanical properties of grey cast iron and different types have totally different characters, six types of grey cast iron are discussed and an image-processing software subsystem that performs the classification and quantitative analysis automatically based on a kind of composed feature vector and artificial neural network (ANN) is described. There are three kinds of texture features: fractal dimension, roughness and two-dimension autoregression, which are used as an extracted feature input vector of ANN classifier. Compared with using only one, the checkout correct precision increased greatly. On the other hand, to achieve the quantitative analysis and show the different types clearly, the region segmentation idea was applied to the system. The percentages of the regions with different type are reported correctly. Furthermore, this paper tentatively introduces a new empirical method to decide the number of ANN hidden nodes, which are usually considered as a difficulty in ANN structure decision. It was found that the optimum hidden node number of the experimental data was the same as that obtained using the new method.     

Simulation of liquid physical blowing agents for forming rigid urethane foams

A computer‐based simulation for rigid polyurethane foam‐forming reactions was compared with experimental data for six blowing agents including methyl formate and C5‐C6 hydrocarbons. Evaporation of blowing agent was modeled as an overall mass transfer coefficient times the difference in activity of the blowing agent in the gas foam cells versus the resin walls of the cells. Successful modeling hinged upon use of a mass transfer coefficient that decreased to near zero as the foam resin approached its gel point. Modeling on density agreed with experimental measurements. The fitted parameters allowed for interpretations of the final disposition of the blowing agent, especially, if the blowing agent successfully led to larger foam cells versus being entrapped in the resin. The only component‐specific fitted parameters used in the modeling was the activity coefficient that was lower for methyl formate than the value used for hydrocarbons. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42454.     

Highly mesoporous carbonaceous material of activated carbon beads for electric double layer capacitor

The activated carbon beads (ACB) are prepared by a new preparation method, which is proposed by mixing the coal tar pitch and fumed silica powder at a certain weight ratio and activation by KOH at different weight ratios and different temperatures. The BET surface area, pore volume and average pore size are obtained based on the nitrogen adsorption isotherms at 77 K by using ASAP 2010 apparatus. The results show that our samples have much high specific surface area (SSA) of 3537 m² g⁻¹and high pore volume value of 3.05 cm³ g⁻¹. The percentage of mesopore volume increases with the weight ratio of KOH/ACB ranging from 4% to 72%. The electrochemical double layer capacitors (EDLCs) are assembled with resultant carbon electrode and electrolyte of 1 mol L⁻¹ Et₄NBF₄/PC. The specific capacitance of the ACB sample could be as high as 191.7 F g⁻¹ by constant current charge/discharge technique, indicating that the ACB presents good characteristics prepared by the method proposed in this work. The investigation of influence of carbon porosity structure on capacitance indicates that the SSA plays an important role on the capacitance and all the pore sizes of less than 1 nm, from 1 to 2 nm and larger than 2 nm contribute to the capacitance. Mesopore structure is beneficial for the performance at high current density.     

The detailed microstructure of an alumina-zirconia-silica (AZS) fused cast refractory material from the cast skin into the bulk analyzed using EBSD

The interface of an industrially-produced block of an alumina-zirconia-silica (AZS) refractory material with the mold is extracted and prepared for analysis. The first 24 mm of crystal growth including the cast skin are analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM) including energy-dispersive X-ray spectrometry (EDXS) and electron backscatter diffraction (EBSD).Apart from the bulk, two chemically different zones of crystallization occur near the interface to the mold. The growth model for this material begins with the primary crystallization of dendritic ZrO₂ followed by secondary crystallization procedures in the respective crystallization zones. The layer adjacent to the mold crystallizes to form alumina, secondary ZrO₂ and mullite. An 001-oriented layer of mullite with the c-axis oriented perpendicular to the mold material is formed in the second layer of crystallization while only alumina, zirconia and residual glass occur further in the bulk.     

Production of carbonaceous material from avocado peel for its application as alternative adsorbent for dyes removal

Adsorption processes have received special attention for contaminants removal thanks to their capability to generate effluents with high quality as well as their simple design. In the current work, the agro-waste residue avocado peel is proposed to be used as alternative to conventional activated carbons whose use is sometimes restricted to high costs, upgraded by their exhausting after long term operations. The carbonization procedure was optimized and analyzed through factorial design and response surface methodology by evaluating temperature(400–900 °C) and time(30–90 min) effects: optimal conditions were found at 900 °C and 65 min, generating an adsorbent with 87.52 m2·g-1of BET surface area, a mesopore volume of 74% and a zero point charge at 8.6. The feasibility of the carbonaceous material was proved for the removal of a variety of dyes by investigating substrate(10–50 mg·L-1) and solid(0.5–20 g·L-1) concentration effects and statistical significance: complete removal of Naphthol Blue Black and Reactive Black 5 was reached under optimal conditions(10 mg·L-1and20 g·L-1of dye and solid, respectively), while Basic Blue 41 was eliminated by using 13.4 g·L-1of the adsorbent.Overall, dyes removal by adsorption on carbonized avocado peel is presented as a promising technology due to the low cost and easy availability of the precursor, as well as the straightforward generation, the satisfactory characteristics and the proved adsorption capacity of the adsorbent.     

The wear of magnesia refractories in electric furnaces for melting cast iron

Conclusions The wear of magnesia refractories, i. e., magnesite, perictase — spinel, and magnesite — chromite bricks and magnesite — phosphate mortar, in the walls of electric furnaces for melting cast iron is the result of the solution predominantly of the periclase crystals and to a lesser extent of the spinel in the lowbasicity ferrosilicate slag melt. Brick of the PShS type proved to be the most durable refractory. The use of high-alumina brick in the roof of the furnaces accelerates the wear of the magnesia bricks in the walls.To increase the durability of the lining of these furnaces trials should be carried out with an all-basic wall lining constructed of high-density PShSP-type brick on MF-1-type magnesite — phosphate mortar and a roof lining constructed of MKhS brick and the same mortar.Translated from Ogneupory, No. 4, pp. 44–49, April, 1976.     

造气炉炉底铸铁灰仓焊补工艺

通过对造气炉炉底灰仓的多次焊补,总结了比较成熟的焊前准备、焊接方法和工艺操作要领及对焊接设备、焊工资格、焊接环境等方面的要求,实践证明,该工艺是成功的.     

Potassium-doped sodalite: A tectoaluminosilicate for the catalytic material towards continuous combustion of carbonaceous matters

A novel approach has been proposed for stabilization of potassium in combustion of carbonaceous soot matters emitted from diesel engine vehicles. Sodalite, a clathrate aluminosilicate zeolite, is employed as a support for holding catalytically active potassium species. This approach resulted in a high-catalytic activity and the activity is further enhanced after hydrothermal treatment at 800 °C. Such kinds of tectoaluminosilicate hold potassium strongly and possess high stability against high temperatures and alkaline conditions induced by hydrated potassium ions under practical driving conditions.