Central composite design application in oil agglomeration of talc

Talc has many applications in various branches of industry. This material is an inert one with a naturally hydrophobic surface. Talc agglomeration is within the wide interest of pharmaceutical industry. Oil agglomeration experiments of talc were carried out to find out and assess the significance of experimental factors. Central composite design (CCD) was used to estimate the importance and interrelation of the agglomeration process parameters. Four experimental factors have been evaluated, i.e. concentration of cationic surfactant and oil, agitation intensity as well as time of the process. The median size of agglomerates (D50) and the polydispersity span (PDI) were used as the process responses. Logarithmic transformations of the responses provide better description of the model, than untransformed responses, with the reduced cubic model for D50 and quadratic model for PDI. This was supported by the Box-Cox plots. It was shown that there were many statistically important factors, including the concentration of cationic surfactant and stirring rate for D50, concentration of oil and stirring rate for PDI, as well as various interactions, up to third order for D50. Optimal conditions for minimum values of reagent amounts as well as mixing time and intensity for the maximum size of agglomerates but of rather narrow size distribution were found

Transport of colloidal particles with arsenic ions adsorbed on the colloidal surfaces through mineral porous bed

Obecność odpadów przemysłowych w środowisku naturalnym staje się coraz bardziej zauważalnym problemem w ochronie środowiska. Za główne źródło ich powstawania, uważa się przemysł wydobywczy i przetwórstwa kopalin. W wyniku prowadzenia procesów wzbogacania, bądź procesów hutniczych, powstają odpady deponowane na hałdach, które w znaczący sposób przyczyniają się do zanieczyszczeń wód gruntowych. Dzieje się tak w wyniku transportu trudno rozpuszczalnych zanieczyszczeń przez naturalny polimineralny ośrodek porowaty. Zjawisko to zostało zaliczone do głównych procesów mających istotny wpływ na zanieczyszczanie wód gruntowych.The storage of insecure industrial waste, descended from mining and metallurgical industry, has an influence on the pollution of a ground and groundwater. It is a result of migration of toxic substances into the bed of soli. The weathering processes and hydrodynamic changes in soil causes the colloidal particles formation, which are effective contaminations carriers through mineral porous media. In this paper transport of colloidal particles: synthetic hematite and natural kaolin has been investigated. The porous medias were waste from both Szklary and Złoty Stok heaps. The aim of this work is to inspect the influence of arsenate ions on the behaviour of colloidal particles in porous bed. The investigations were conducted in two ionic strengths: 5ź10-3 M KCl and 5ź10-4 M KCl, at pH 9.2-11.6. Results showed that transport of colloidal hematite was facilitated, when arsenic ions were adsorbed onto the colloid particles. Additionally, the increase of mobility of hematite was caused by a decrease of ionic strength. In the case of kaolin transport, the results showed an increase of kaolin particles migration without arsenic ions. These behaviour of colloidal kaolin particles into mineral bed isexplained by different surface property of kaolin particles. Results of examinations on colloidal particles of hematite and kaolin transport through column with mineral bed show, that examined mobility is conditioned with physico-chemical proprieties of colloidal particles and materials of porous bed. Studied colloids, can influence pollution of underground waters in the areas of storing of studied industrial wastes. Results of conducted measurements show, that the process of examined colloidal particles transport is influenced by presence of adsorbed arsenic ions. It is the most perceptible phenomenon in the case of the colloidal hematite, particularly for porous medium built from materials taken from the southern side of heap in Szklary and heap in Złot Stok. Additionally, influence of ion strength on quantity of transported colloidal particles through the layer of porous mineral medium was observed. When ion strength was decreasing, the thickness of the double electric layer increases on colloidal particles. It has impact on decrease of attracting interactions among particles of colloid, and also between colloidal particle and grain of mineral bed. The opposite case was noted during investigations on transportation of colloidal particles of kaolin. Adsorption of arsenic ions by particles of kaolin causes decrease of their mobility. This causes stopping of migration of arsenic ions to underground waters. The similar result is obtained when ion strength is enlarged

The oil agglomeration of magnesite rock with participation of ionic surfactants mixtures

In this study, the adsorption of surfactant onto the magensite rock and the oil agglomeration of this mineral in aqueous suspension were investigated. The various concentration ratios of cationic and anionic surfactant were used. The results were evaluated by the recovery of carbonates in agglomerates. It was found that the process selectivity was highly dependent on the surfactants concentration ratio, pH, and the amount of salt added. The best separation of quartz from magnesite rock was observed at pH 9. The addition of larger quantity of sodium oleate (15.2 mg/gsolid) led to the increase of carbonates content in agglomerates up to 32.4%. However, the largest carbonates recovery was in the presence of 6.0 mg/gsolid of NaOl

Transport jonów metali przez piasek kwarcowy

Migracja jonów metali przez porowatym ośrodku, utworzony z ziaren mineralnych, ma istotne znaczenie w takich procesach jak ługowanie i bioługowanie oraz w szeregu procesach biogeochemicznych. Transport toksycznych metali w stanowi poważny problem w ochronie środowiska naturalnego i powinien być dokładnie zbadany. W pracy przedstawiono wyniki badań migracji jonów Ni(II), Cr(III) i Pb(II) przez porowaty ośrodek utworzony przez piasek kwarcowy. Doświadczenia zostały przeprowadzone z wykorzystaniem poziomo usytuowanej rury, wypełnionej piskiem kwarcowym. Powierzchnia ziaren kwarcu była modyfikowana przez działanie kationowego (CTAB) i anionowego surfaktantu. Efektywność migracji jonów przez porowaty ośrodek mineralny była kontrolowana przez analizę profilu stężeń kationu w złożu. Adsorpcja kationowego surfaktantu sprzyja adsorpcji jonów do ziaren kwarcu. Odwrotnie, obecność anionowego surfaktantu sprzyja migracji jonów. Obecność CTAB w badanym złożu kwarcowym powodowała wzrost adsorpcji adsorpcji jonów metali na powierzchni złoża. Obecność SDS spowodowała wzrost mobilności metali bardziej niż wzrost prędkości przepływu wody i znacząco zmniejszyła adsorpcję jonów na powierzchni piasku. Anionowe surfaktanty są szeroko stosowane do odzysku oleju, przede wszystkim dzięki ich małej tendencji do adsorbowania, stabilności w wysokiej temperaturze i ciśnieniu i niskich kosztach [11]. Badania sugerują, że te surfaktanty mogą być użyteczne w usuwaniu metali. Mobilność badanych metali w piasku kwarcowym wzrasta w kolejności: Ni (II) > Cr (III) > Pb (II) i wpływa na nią obecność anionowych surfaktantów i wzrost przepływu wod

Calcium carbonate mineralization. Part 1, The effect of poly(ethylene glycol) concentration on the formation of precipitate

In this study, the role of polymer in precipitation has been examined by studying the effect of poly(ethylene glycol) (PEG) on the formation of calcium carbonate particles. The CaCO3 particles were characterized by several techniques, such as FTIR, XRD, SEM, and particle size distribution analysis. In the absence of polymer, the mixing of reagents in an aqueous solution led to the formation of calcite crystals. Introduction of poly(ethylene glycol) molecules reduced the rate of crystallization process, and the effect was concentration dependent. In the presence of 0.05, 0.1, and 0.5 % of PEG, after 5 minutes of precipitation initiation, vaterite microspheres appeared in the system and which were transformed into calcite crystals after 24 hours. The calcium carbonate obtained with PEG was characterized by smaller sized particles in comparison with the ones without polymer

Oil agglomeration of metal-bearing shale in the presence of mixed cationic-anionic surfactants

This paper reports oil agglomeration of fine metal-bearing shale particles in the presence of cationic (dodecylamine hydrochloride) and anionic (sodium dodecyl sulfate) surfactants and their mixture. The experimental results demonstrated that there was a strong relationship between zeta potential, hydrophobic coagulation, oil agglomeration and particle hydrophobicity in the presence of cationic surfactant, whereas shale neither coagulated nor agglomerated in the presence of anionic surfactant. Addition of either anionic or cationic surfactant in emulsification of a bridging oil increased the size of agglomerates and reduced the concentration of surfactant used in the suspension. The results pointed to synergism between cationic and anionic surfactants in oil agglomeration. Based on the results obtained from this study, the mechanism of oil agglomeration of shale in the presence of ionic surfactants and their mixture was elucidated

Extraction of organic impurities using 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF 6

Extraction of several chloro compounds from water has been examined. As the extracting liquid the 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF6], which is common hydrophobic ionic liquid, was used. Additionally, extraction of selected chlorinated compounds from tert-butylmethylether (MTBE) was investigated. The obtained results show the usefulness of [BMIM][PF6] to remove the organic impurities from water, particularly at the concentration range inappropriate for biological purification plants

Use of fly ash and fly ash agglomerates for As(III) adsorption from aqueous solution

The objective of the present study is to assess the efficiency of fly ash and fly ash agglomerates to remove arsenic(III) from aqueous solution. The maximum static uptakes were achieved to be 13.5 and 5.7 mgAs(III)/adsorbent for nonagglomerated material and agglomerated one, respectively. Isotherm studies showed good fit with the Langmuir (fly ash) and the Freundlich (fly ash agglomerates) isotherm models. Kinetic studies indicated that the sorption of arsenic on fly ash and its agglomerates follows the pseudo-second-order (PSO) chemisorption model (R2 = 0.999). Thermodynamic parameters revealed an endothermic nature of As(III) adsorption on such adsorbents. The adsorption results confirmed that fly ash and its agglomerates can be used for As(III) removal from aqueous solutions. Fly ash can adsorb more arsenic(III) than agglomerates, which are easier to use, because this material is less dusty and easier to separate from solution

Calcium carbonate mineralization. Part II: effect of poly(ethylene glycol) and block copolymers molecular weight on formation of precipitate

In this study the role of PEG and PEO-PPO-PEO block copolymers molecular weight in precipitation of calcium carbonate was examined. The CaCO3 particles were characterized by FTIR spectroscopy, X-ray, SEM and particle size distribution analysis. In absence and presence of modifiers, mixing of the reagents led to the formation of calcite crystals. The calcium carbonate obtained with poly(ethylene glycol) and block copolymers was characterized by smaller diameter in comparison with the one without modifiers. It was observed that using compounds with different molecular weights has no obvious effect on the form and properties of precipitated calcium carbonate particles

Use of fly ash and fly ash agglomerates for As(III) adsorption from aqueous solution

The objective of the present study is to assess the efficiency of fly ash and fly ash agglomerates to remove arsenic(III) from aqueous solution. The maximum static uptakes were achieved to be 13.5 and 5.7 mgAs(III)/adsorbent for nonagglomerated material and agglomerated one, respectively. Isotherm studies showed good fit with the Langmuir (fly ash) and the Freundlich (fly ash agglomerates) isotherm models. Kinetic studies indicated that the sorption of arsenic on fly ash and its agglomerates follows the pseudo-second-order (PSO) chemisorption model (R2 = 0.999). Thermodynamic parameters revealed an endothermic nature of As(III) adsorption on such adsorbents. The adsorption results confirmed that fly ash and its agglomerates can be used for As(III) removal from aqueous solutions. Fly ash can adsorb more arsenic(III) than agglomerates, which are easier to use, because this material is less dusty and easier to separate from solution