The study on the effect of flotation purification on the performance of α-hemihydrate gypsum prepared from phosphogypsum

Phosphogypsum (PG) is a massive industrial solid waste. In this paper, PG was purified by flotation method, and α-hemihydrate gypsum (α-HH) was prepared by the autoclaving method. The morphology of α-HH was adjusted by adding different doses of Maleic acid and Aluminium sulfate. The results showed that after flotation purification, the impurity content in PG was significantly reduced, the soluble phosphorus content decreased from 0.48 to 0.07%, the PG purity increased from 73.12 to 94.37%, and the PG whiteness risen from 19.4 to 40.5. Then the performance of α-HH prepared from PG before and after purification was compared. Fixing the amount of aluminium sulfate at 0.2 wt%, the reaction temperature at 140 °C, and the reaction time at 120 min, the average length/diameter ratio of α-HH crystals decreased from 7.2 to 0.6 as the amount of Maleic acid increased from 0 to 0.17 wt%. When the amount of Maleic acid was 0.13 wt%, the α-hemihydrate gypsum reached the best mechanical properties. The mechanical strength of high strength gypsum prepared from PG concentrate was significantly better than that of raw PG, indicating that flotation purification can effectively improve the performance of PG. In this study, a new method of PG purification and resource utilization was proposed.

Soil contamination by Ancylostoma spp. and Toxocara spp. eggs in elementary school playgrounds in the extreme south of Brazil

Millions of people worldwide, and especially schoolchildren, may be infected by geohelminths due to their exposure to a contaminated environment. The aim of this study was to evaluate soil contamination by Ancylostoma spp. and Toxocara spp. eggs in recreation areas at elementary schools in Pelotas, state of Rio Grande do Sul, Brazil. Sand samples were collected from 22 schools and were processed using the centrifugal flotation method. Helminth eggs with zoonotic potential were found in 12 out of the 22 schools (54.5%). Contamination by Ancylostoma spp. and Toxocara spp. was observed in 36.4% (8/22) and 27.3% (6/22) of the soil samples collected at these schools, respectively. These findings of eggs show that the school communities are exposed to risks of zoonotic transmission.

Identifikasi Telur Soil Transmitted Helminths Pada Caisim (Brassica chinensis) di Pasar Patikraja Kabupaten Banyumas

Caisim (Brassica chinensis) is one of the vegetables that has many benefits such as protein, carbohydrates, fat and plays an important role in meeting food needs, and is good for health. Caisim is well adapted to high temperatures and the price is relatively stable and easy to cultivate. The purpose of this study was to determine the presence of Soil-Transmitted Helminths eggs in caisim (B. chinensis). The research was conducted in a descriptive observational. The research was conducted in July-August 2020 at Parasitology and Microbiology Laboratory, Faculty of Medicine, Universitas Muhammadiyah Purwokerto. Identification of Soil-Transmitted Helminths eggs from 20 caisim as the samples used NaCl flotation method and were analyzed by using a univariate test with tabulated frequency distribution. The results showed that no Soil-Transmitted Helminths eggs were found in caisim (B. chinensis). Caisim (Brassica chinensis) merupakan sayuran yang mempunyai banyak kandungan manfaat seperti protein,karbohidrat, lemak dan berperan penting untuk memenuhi kebutuhan pangan serta baik untuk kesehatan. Caisimmampu beradaptasi dengan baik terhadap suhu tinggi serta harga relatif stabil dan mudah diusahakan. Tujuanpenelitian ini untuk mengetahui adanya telur Soil Transmitted Helminths terdapat pada caisim (B. chinensis).Penelitian dilakukan secara observasional deskriptif. Penelitian dilakukan pada bulan Juli-Agustus 2020 diLaboratorium Parasitologi Fakultas Kedokteran Universitas Muhammadiyah Purwokwerto. Identifikasi telur SoilTransmitted Helminthsdari 20 sampel caisim dengan metode Flotasi NaCl. dianalisis dengan uji univariat dengandistribusi tabulasi frekuensi. Hasil penelitian menunjukan tidak ditemukan telur Soil Transmitted Helminths padacaisim (B. chinensis)

Tachinobia sp. (Hymenoptera: Eulophidae) as parasitoid of Peckia Sarcodexia) lambens (Wiedemann, 1830) (Diptera: Sarcophagidae)

Insect parasitoids have an immature life stage that develops on or within a single insect host, ultimately killing the host, hence the value of parasitoids as natural enemies. This work reports the first occurrence of parasitoid Tachinobia sp. (Hymenoptera: Eulophidae) as parasitoid Peckia (Sarcodexia) lambens (Wiedemann, 1830) (Diptera: Sarcophagidae). The pupae were obtained by the flotation method. They were individually placed in gelatin capsules until the emergence of flies or their parasitoids. In November 2013, six pupae were obtained from P. (S) lambens, of which two pupae twelve specimens emerged Tachinobia sp. The percentage of parasitism was 33.3%. Most insect parasitoids only attack a particular life stage of one or several related species. The immature parasitoid develops on or within a pest, feeding on body fluids and organs, eventually leaving the host to pupate or emerging as an adult.

Development of Flotation Device for Removing Unburnt Carbon in Fly Ash for Use in Hardened Cementitious Materials

The unburned carbon in fly ash inhibits the performance of concrete. A device using the flotation method to remove unburned carbon in fly ash was developed, and the operating condition of the device was experimentally examined. According to the results, the device was able to remove unburnt carbon from fly ash by using the installed micro bubble nozzles and a whirl-type pump. The removal efficiency of unburnt carbon improved when prior forced stirring was carried out by a concrete mixer for 3 min, and a scavenger was added into the fly ash slurry at a density of about 60 wt%. It has also been confirmed that the method of circulating water is more effective than the method of not circulating water. The elements of the modified fly ash slurry (MFAS) have also been experimentally confirmed as not being too different from untreated fly ash, except for the fact that the content of unburned carbon is reduced. The compressive strength and drying shrinkage characteristics of concrete made with MFAS were investigated. The use of MFAS will reduce the performance of concrete compared to that of ordinary concrete. This shows that in a certain range (15–30%), the influence of MFAS on drying shrinkage is constant. The static elastic modulus and dynamic elastic modulus were also investigated. The above results show that the application of MFAS prepared by the flotation method to concrete is feasible.

Removal of chromium (VI) ions from aqueous solutions

The object of the research is the flotoextraction of chromium (VI) ions from model and real waste waters. Hexavalent chromium compounds pose a serious hazard to surface and ground waters and can have mutagenic and carcinogenic effects on living organisms. The study of the process of flotoextraction as a method of purifying waste water from heavy metals using the example of chromium (VI) ions is an important task. The paper considers flotoextraction of chromium (VI) ions using a cationic surfactant – hexadecylpyridinium chloride and butyl alcohol as the organic phase. The dependences of the process efficiency on the presence of a cationic surfactant, the flotoextraction time, the type of organic extractant, the nature of the collector and the surfactant: Cr molar ratio, the initial concentration of pollutants, and the pH of the initial solution were obtained. Certain rational conditions for flotation allow removing 98–99.6 % of pollutants. The method was tested on real wastewater. The importance of this study is emphasized by the fact that flotoextraction has a number of features and advantages. In particular, the possibility of multiple concentration of pollutant ions in small volumes of an organic solvent and the possibility of its further regeneration. In this case, a much smaller amount of an organic solvent is used and the process is not limited by the distribution constant (compared to the extraction method). Flotoextraction is also characterized by the absence of foam (compared to the flotation method) and the absence of large amounts of wet sludge (compared to the reagent method). The proposed method provides a sufficient level of chromium ions removal from wastewater, and can also be used in systems for local wastewater treatment with the subsequent return of water to the technological process. This will ensure a reduction in costs for the consumption of water resources, discharge of wastewater into water bodies, and also limit the ingress of harmful substances into the environment.

Beneficiation of Faya Clay for Drilling Mud Production Using Froth Floatation and Jig Gravity Concentration Techniques

The comparative study for upgrading Faya clay, in Faya Town of Plateau State, Nigeria to oil and Gas drilling mud grade was carried out. The clay was sourced from three veins A, B, and C. The samples were homogenized, crushed and ground. 5 kg of the homogenized sample was used for the experiment and laboratory work. Chemical and mineralogical characterization of the clay sample was carried out using; X-ray fluorescence (XRF) and X-ray diffractorneter (XRD). The clay sample was beneficiated using two methods: froth flotation and gravity concentration method (Jigging). The chemical composition of the crude clay revealed that it contains 16.6% Al2O3, 35.6% SiO2, 0.559% K2O, 0.084% CaO, 6.133% Fe2O3, 0.91 % TiO2 and 38.7 % BaO. The result of XRD analysis shows that quartz is predominant in the sample with 61.7% wt quartz (SiO2). Other minerals found in the sample include 28.59% wt of dickite (Al2 Si205 (0H)), 8.89% wt goethite (Fe0 (0H 4) and 0.83% wt muscovite (KO.92 NaO.08) (Al.86 FeO.07 TiO.02) (Si.3 O.3 AlO.97) O10 (OH)2 at 2 . Froth flotation method is more efficient for the beneficiation of Faya clay as it improves the BaO composition of the clay from 38.7% to 52.2%, with a recovery of 97.2%, an enrichment and ratio of concentration of 1.4 compared with the jigging method, which improved BaO composition from 38.7% in the crude clay to 47.5%, with a recovery of 90.96% and an enrichment ratio of 0.7; and ratio of concentration of 0.7. Froth floatation improved the specific gravity of the clay from 3.3 to 4.31; while jigging improved the specific gravity from 3.3 to 4. 05. Therefore, froth flotation method is more appropriate for the concentration of Faya clay ahead of jigging method of processing.Keywords: Upgrading, Characterization, Faya - clay, Drilling, Production

Comparative Study of α-Hemihydrate Preparation from Phosphogypsum Before and After Flotation Purification

Phosphogypsum (PG) is a massive industrial solid waste. In this paper, PG was purified by flotation method, and α-hemihydrate gypsum (α-HH) was prepared by the autoclaving method. The morphology of α-HH was adjusted by adding different doses of Maleic acid and Aluminium sulfate. The results showed that after flotation purification, the impurity content in PG was significantly reduced, the soluble phosphorus content decreased from 0.48% to 0.07%, the PG purity increased from 73.12% to 94.37%, and the PG whiteness risen from 19.4 to 40.5. Then the performance of α-HH prepared from PG before and after purification was compared. Fixing the amount of Aluminium sulfate at 0.2wt%, the reaction temperature at 140°C, and the reaction time at 120min, the average length/diameter ratio of α-HH crystals decreased from 7.2 to 0.6 as the amount of Maleic acid increased from 0 to 0.17wt%. When the amount of Maleic acid was 0.13wt%, the α-hemihydrate gypsum reached the best mechanical properties. The mechanical strength of high strength gypsum prepared from PG concentrate was significantly better than that of raw PG, indicating that flotation purification can effectively improve the performance of PG. In this study, a new method of PG purification and resource utilization was proposed.