Effects of embedding direct reduction followed by magnetic separation on recovering titanium and iron of beach titanomagnetite concentrate

Embedding direct reduction followed by magnetic separation was conducted to fully recover iron and titanium separately from beach titanomagnetite(TTM).The influences of reduction conditions,such as molar ratio of C to Fe,reduction time,and reduction temperature,were studied.The results showed that the TTM concentrate was reduced to iron and iron-titanium oxides,depending on the reduction time,and the reduction sequence at 1 200°C was suggested as follows:Fe_(2.75)Ti_(0.25)O_4→Fe_2TiO_4→FeTiO_3→FeTi_2O_5.The reduction temperature played a considerable role in the reduction of TTM concentrates.Increasing temperature from 1 100 to 1 200°C was beneficial to recovering titanium and iron,whereas the results deteriorated as temperature increased further.The results of X-ray diffraction and scanning electron microscopy analyses showed that low temperature(≤1 100°C)was unfavorable for the gasification of reductant,resulting in insufficient reducing atmosphere in the reduction process.The molten phase was formed at high temperatures of 1 250-1 300°C,which accelerated the migration rate of metallic particles and suppressed the diffusion of reduction gas,resulting in poor reduction.The optimum conditions for reducing TTM concentrate are as follows:molar ratio of C to Fe of 1.68,reduction time of 150 min,and reduction temperature of 1 200°C.Under these conditions,direct reduction iron powder,assaying 90.28 mass%TFe and 1.73 mass% TiO_2 with iron recovery of 90.85%,and titanium concentrate,assaying 46.24mass% TiO_2 with TiO_2 recovery of 91.15%,were obtained.     

Functional properties of sonicated and non-sonicated extracted leaf protein concentrate from Diplazium esculentum

Leaf protein concentrate of edible fern Diplazium esculentum was extracted using sonication and non-sonication methods and its functional properties were evaluated. The leaf protein concentrate contained 34.28 and 9.89% protein for sonicated and non-sonicated extractions, respectively. Sonication yielded (36.36%) better emulsion activity over non-sonication (31.10%). Foaming capacity was also found better in sonication (7.27%) over non-sonication (6.99%), and oil absorption capacity also improved in sonication (7.55 g of oil/g) over its counterpart (7.41 g of oil/g). Contact angle experiments with the leaf protein concentrate evidenced the enhancement of more hydrophilicity of the sonicated sample. Thermal properties of the leaf protein concentrate with sonication evidenced more stability (55.58 and 95.95°C) over the non-sonicated (46.75 and 75.60°C). Fourier transform infrared spectral analysis with the leaf protein concentrate of Diplazium esculentum was used to assess the secondary structural data such as α-helix and β-sheets. The various percentages of secondary structures of protein in sonicated and non-sonicated samples were 49.06 and 69.16% for α-helix, 33.59% and 17.02% for β-sheet and 42.02 and 35.68% for turn, respectively. The results of the present investigation showed credible evidence to support that sonication method of extraction of leaf protein concentrate was better in terms of protein yield and functional properties as compared to the non-sonication. The sonicated extracted leaf protein concentrate has the potential for developing value added products.     

活性炭吸附原子吸收光度法测定铅锑精矿中金的含量

通过在铅锑精矿焙烧时加入一定量的氧化锌或氧化钙，使铅锑精矿在灼烧过程中的单质硫、有机质、硫化物、碳充分焙烧，然后采用王水分解矿样，活性炭动态吸附富集金，灰化除碳，王水溶解，原子吸收光度法测定铅锑精矿中金含量，方法快速、准确，同时适用于含碳、硫较高焙烧时易结块的精矿样品。     

Chitosan coatings enriched with active shrimp waste for shrimp preservation

An active coating solution composed of chitosan (Ch) and a shrimp protein-lipid concentrate (PCc), both obtained from Litopenaeus vannamei processing wastes, was applied to preserve shrimp during chilled storage. The addition of PCc increased the antioxidant capacity of the Ch coating, yielding a lower-viscosity mixture which, however, was viscous enough to adhere to the shrimp while maintaining its activity. The shrimp storage trial showed that the Ch coatings, especially when enriched with PCc (Ch-PCc), delayed microbial growth, mainly by extending the lag phase. Pseudomonas spp. appeared to be the predominant bacteria in the microbiota. H₂S-producing organisms and luminescent colonies were especially sensitive to this active coating, with inhibition greater than 4 and 2 log cycle respectively, while the growth of lactic acid bacteria was not favored. The Ch-PCc coating delayed the onset of melanosis and did not confer any sensorially detectable color, taste or odor. It therefore shows promise as a means to improve the quality of shrimp during cold storage.     

Anthocyanin profile of red fruits and black carrot juices,purees and concentrates by HPLC‐DAD‐ESI/MS‐QTOF

A fast and reliable method for anthocyanin extraction and identification by HPLC‐DAD‐ESI/MS‐QTOF was used to analyse the anthocyanin composition of commercial red fruit juices (blackberry, redcurrant and pomegranate), purees (strawberry, cherry and raspberry) and concentrates (elderberry, blueberry and red grape). The anthocyanin profile of black carrot juice is also reported. The extraction and analysis method allowed us to detect and quantify a wide range of individual anthocyanins in a simple and rapid way. Pelargonidin‐3‐glucoside was detected in redcurrant for the first time and petunidin‐3‐galactoside quantified for the first time in blueberries. Considering the health benefits that have been associated with anthocyanin consumption, all these fruit and vegetables processed products could appear as a good source of this group of phytochemical compounds for their direct consumption or their use as ingredients for the design of new food product or food supplements.     

Influence of pH on colour and iron content of peptide fractions obtained from bovine Hb concentrate hydrolysates

The effect of pH on colour and iron content (Fe) of peptide fractions obtained from bovine haemoglobin concentrate (BHC) hydrolysates was studied. Four hydrolysates were obtained using three enzymes: Protex‐6‐L (P), Fungal–Protease–Concetrate (FC) and Flavourzyme (F). BHC and its hydrolysates (P, FC, P + F, FC + F) were fractioned at pH 4.5, 7.0 and 9.5. Solubility and Fe from different fractions were measured. Correlations between CIELAB colour parameters and Fe from different fractions were analysed. The colour from different fractions varied from red to yellow (a* and b* positives). Lightness values (L*) ranged from twenty‐four to seventy. FC4.5 and FC + F4.5 fractions were the clearest and yellow (higher L*, b*, h), while BHC9.5 and P + F9.5 fractions had the lowest values of L*, b* and h. There was an inverse linear relationship between b* and L* parameters and Fe from fractions. This relationship could be associated with the pH of extraction. As pH increases Fe significantly increases and lower b* and L* values were obtained.     

Effect of freezing on the viscoelastic behaviour of whey protein concentrate suspensions

The effect of freezing on viscoelastic behaviour of whey protein concentrate (WPC) suspensions was studied. Suspensions with total protein content of 5% and 9% w/v were prepared from a commercial WPC (unheated suspensions). A group of unheated suspensions was treated at two temperatures (72.5 and 77.5 °C) during selected times to obtain 60% of soluble protein aggregates (heat-treated suspensions). Unheated suspensions and heat-treated suspensions were frozen at −25 °C (frozen unheated and frozen heat-treated suspensions). Frequency sweeps (0.01–10 Hz) were performed in the region of linear viscoelasticity at 10, 20, 30, 40, and 50 °C. Mechanical spectra of all studied suspensions at 20 °C were similar to viscoelastic fluids and complex viscosity increased with the frequency (ω). Elastic (G′) and viscous (G″) moduli were modelled using power law equations (G′ = aω^x, G″ = bω^y), using fitted parameters a, x, b, and y for statistical analysis. Exponent y was the most influenced by freezing, indicating the existence of a higher degree of arrangement in frozen unheated suspensions and a lower degree of arrangement in frozen heat-treated suspensions. Only characteristic relaxation times (inverse of the crossover frequency) of suspensions with 5% w/v of total protein content were significantly influenced by freezing. Time–temperature superposition was satisfactory applied in unheated whey protein concentrate suspensions only in the range of high temperatures (30–50 °C). However, this principle failed over the complete temperature range in most of the frozen suspensions. It is possible that freezing produced an increase in the susceptibility to morphological changes with temperature during the rheological measurements.     

己内酰胺浓缩液直接回用的工艺技术

阐述了己内酰胺浓缩液直接聚合理论 ,对 PE公司 ,Aquafil公司 ,Inventa-Fischer公司和岳阳石油化工总厂在锦纶 6切片生产中己内酰胺浓缩液直接回用的工艺技术及其特点进行了介绍 ,讨论了浓缩液直接聚合时 ,水含量 ,聚合时间 ,聚合温度的影响     

某复杂铜铅锌多金属硫化矿选矿试验研究

根据某铜铅锌矿矿石中铜、铅、锌等硫化矿物嵌布关系复杂、嵌布粒度极不均匀的特点,采用"铜铅混合浮选—混合精矿再磨—铜铅分离—混合浮选尾矿选锌"的工艺流程及合理的药剂制度,闭路试验获得良好的铜、铅、锌选矿技术指标,同时,矿石中的伴生银也得到了较好回收,铜、铅、锌及银的回收率分别达到65.98%、88.83%、85.31%、84.98%。     

某含铅锌金矿石全泥氰化—尾渣浮选铅锌试验研究

某含铅锌金矿石中金属硫化物之间存在较复杂的矿物共生关系,以减少金的损失为优先条件,通过选矿试验研究,采用原矿全泥氰化;尾渣浮选铅锌工艺流程,金回收率达到95.69%,同时获得合格铅精矿和锌精矿,铅精矿品位66.41%、回收率79.24%,锌精矿品位51.88%、回收率89.49%。