THE REACTIVITY AND DURABILITY OF ZINC FERRITE HIGH TEMPERATURE DESULFURIZATION SORBENTS

Cylindrical pellets of zinc ferrite high temperature desulfurization sorbent have been prepared using a number of formulation recipes and induration conditions. Physical and structural properties of the resultant sorbents were measured, and reactivity and durability screening tests were carried out using a single pellet electrobalance reactor. The formulation variables studied were ZnO to Fe₂O₃ ratio, Fe₂O₃ source, and the addition of inorganic (bentonite) and organic (methocel) binders to the sorbents. Pellet induration conditions ranged from 0.25 hours at 815^°C to 4.0 hours at 1038°C. Stronger pellets having greater attrition resistance resulted when 5% bentonite was added to the formulation recipe and when the pellets were indurated at high temperature for extended times. In contrast, bentonite content was not a significant factor in determining sorbent reactivity and durability, both of which were improved by mild induration conditions. Sorbent regeneration temperature was found to be an important factor in improving reaction durability, as was the addition of 0.5% methocel to the formulation recipe. Pellets containing catalyst-grade Fe₂O₃ were more reactive than those containing pigment-grade Fe₂O₃. This effect, however, was less important than the effect of induration conditions.     

Storage stability of a high protein food beverage powder prepared from the Nigerian ‘red skin’ groundnut (Arachis hypogaea) protein concentrates

A high protein, groundnut-based powder reconstitutable into a milk-like beverage was packed in polyethylene bags and in lacquered tin cans, and stored at both room temperature (25 ± 2°C) and in a domestic refrigerator (5 ± 2°C) for 60 days. Storage stability was evaluated by analysing periodically for changes in physical characteristics, proximate composition, and development of browning and rancidity, and assessing moisture sorption characteristics. Protein, lipid, total soluble sugars, peroxide value, total carbonyls and extinction values of the ethanolic extract remained practically constant during storage. The isotherm curves exhibited the characteristic sigmoidal shape typical of high protein foods. There was a greater increase in density, hygroscopicity and wettability in polyethylene-packed samples at both temperatures suggesting that the lacquered tin can leads to better keeping quality for this product.     

Emulsifying Capacity and Emulsion Stability of Soy Proteins Compared with Corn Germ Protein Flour

Both emulsifying capacity (EC) and emulsion stability (ES) increased with increasing concentrations from 0.4% to 0.8% of soy flour (SF), soy concentrate (SC), soy isolate (SI) and corn germ protein flour (CGPF) when studied by response surface methodology. EC and ES increased as pH increased from 6 to 8 in all samples. Increasing incubation temperatures of protein solutions from 20–70°C or from 4–20°C did not affect EC or ES, respectively. SF had the highest EC, followd by SI, SC, and CGPF.     

浅析铂钯精矿的提取技术

本文简述湿法工艺提取铂钯金属精矿的工艺技术及主要生产过程     

用气相色谱测定液氧中乙炔及其他碳氢化合物的含量

利用气相色谱浓缩法和气相色谱直接法测定液氧中乙炔及其他碳氢化合物含量。通过比较。用气相色谱直接法测定，方法简便，快捷，准确。     

Corrosion failure of Zn–Al detonator housing

Some batches of detonator housings made up of Chromium plated Zn–Al alloy were found in an extensively cracked condition after few months of storage at room temperature. An analysis of the failure showed that the cracks were due to intergranular corrosion facilitated by segregation of lead at the grain boundaries. Improper chromium plating further aggravated the corrosion problem. This failure case emphasises the need for strict control of chemical composition for components made from Zn–Al alloy and the process of Cr plating of the components.     

Characterisation of inter-particle forces within agglomerated metallurgical powders

The strength of agglomerates of nickel flash furnace concentrate and dust was determined from experimental observations of agglomerates forming under controlled conditions, combined with mathematical equations from the literature. It was found that the agglomerates had a tensile strength ranging from 0.01 Pa to 38.7 Pa, while inter-particle forces ranged from 2.2 × 10^− 12 N to 1.5 × 10^− 10 N. These values were compared to the expected magnitude of van der Waals, electrostatic, magnetic and capillary forces within the agglomerates, and it was found that both electrostatic and van der Waals forces are likely to contribute to the cohesion of agglomerates, although sub-micron particles and the presence of sufficiently large asperities on the surface of particles limit the magnitude of van der Waals forces. Magnetic forces are large enough to contribute to the cohesion of dust agglomerates, which is in keeping with the high magnetite content of the recycle dust. It is postulated that electrostatic forces, acting over a longer range than van der Waals forces, may be responsible for initially bringing particles together. The methodology for determining inter-particle forces can be applied to the computer modelling of flash smelting systems, as well as other gas/particle systems such as fluidized beds.