Silicon saturation coefficient changes in hydrogarnets during the Bayer process with lime addition

The relationship between the silicon saturation coefficient of hydrogarnets and Bayer reaction parameters was studied. The peak position, crystal plane spacing, and cell edge length of typical hydrogarnet patterns were calculated to find the key factors influencing the relationship. The results showed that the crystal face(420) is the optimal garnet growth direction during hydration and crystal growth along the faces(521) and(611) were not affected significantly by the varying experimental conditions. The reaction temperature significantly influenced the silicon saturation coefficient of hydrogarnets. The silicon saturation coefficient of hydrogarnets increased from 0.2 to about 1.0 in the temperature range of 30–270 °C and a rapid expansion process was observed in the temperature range of 120–150 °C. Moreover, the reaction time, alumina concentration, and C/S were shown to be less important factors. Averaging the results obtained by the 3 methods was shown suitable for calculating the SiO2 saturation coefficient of hydrogarnets. The calculated results of the Al2O3 and SiO2 contents matched the actual ones. However, the actual SiO2 content was about10 % less than the calculated one for SiO2 saturation coefficients higher than 1.

Analysis and Study on Quality Control of Yao Medicine Damnacanthus macrophyllus Based on Methods in Chinese Pharmacopoeia

[Objectives]To establish a quality analysis method for Yao medicine Damnacanthus macrophyllus Sieb.ex Miq.var.giganteus(Makino)Koidz..[D.indicus Gaertn.f.var.giganteus Makino].[Methods]The moisture,total ash and alcohol extracts of D.macrophyllus medicinal materials were determined according to the experimental methods in the Chinese Pharmacopoeia(2020).[Results]All the 10 batches of D.macrophyllus medicinal materials from different collection times and different regions in Guangxi had the same plant morphological characteristics.The experimental results indicate that the moisture was 9.81%-11.52%,the total ash content was 7.37%-9.53%,the acid-insoluble ash content was 1.10%-1.97%,and the extract was 8.25%-10.22%.[Conclusions]This study provides a scientific basis for establishing a quality standard for Yao medicine D.macrophyllus medicinal materials,and it is expected to better utilize and develop D.macrophyllus.

Analysis on Quality Control of Argyreia acuta Lour

[Objectives]To establish a method for caffeic acid content determination and thin-layer chromatography identification of the Zhuang medicine Argyreia acuta Lour.[Methods]Silica gel GF254(thin-layer plate),toluene-formic acid-ethyl acetate(V∶V∶V=5∶1.2∶3)(developing agent)and 365 nm ultraviolet light were used for thin-layer chromatography identification.Under the chromatographic conditions of column of Thermo SCIENTIFIC Hypersil C18(5μm,4.60 mm×250 mm),mobile phase of methanol-0.1%phosphoric acid(23∶77),detection wavelength of 320 nm,column temperature of 30℃,sample size of 10μL and flow rate of 1.0 mL/min,the content of caffeic acid in A.acuta Lour was determined.[Results]Caffeic acid can be detected in thin layer chromatography,with strong specificity and clear spots.When the sample size of caffeic acid is within the range of 0.0151-0.4530μg(R^(2)=0.9999),the content of caffeic acid showed a relatively good linear relationship with the peak area.The average recovery rate of A.acuta Lour was 99.94%(RSD=2.68%),97.56%(RSD=1.57%)and 99.79%(RSD=2.05%),respectively.[Conclusions]This method can effectively identify A.acuta Lour,and can accurately determine the content of caffeic acid in A.acuta Lour.It has characteristics of high accuracy,high precision,good color rendering stability,good reproducibility and fast analysis speed.