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EN
Dolomite is a common carbonate mineral that can release CO2 gas under acidic conditions. The formation of bubbles on the dolomite surface might play a critical role in the flotation separation of dolomite from apatite. In this study, the CO2 bubbles formation due to CO2 gas releasing from the dolomite surface under acidic condition was observed using an atomic force microscope (AFM). The influence of CO2 bubbles on flotation behavior and surface wettability of dolomite was evaluated through micro-flotation test, contact angle measurement and molecular dynamics simulation. The results indicate that no gas phase points were observed on the dolomite surface in deionized water or sodium oleate (NaOL) solution. CO2 nanobubbles were observed on the dolomite surface treated with NaOL solution at pH 5, with an average size of 44 nm. The presence of CO2 gas layers has a shielding effect on the adsorption of water molecules on the dolomite surface, potentially enhancing the surface hydrophobicity of dolomite. Therefore, CO2 bubbles are beneficial for improving flotation recovery of dolomite. This study inspires the idea of utilizing the released CO2 bubbles in the flotation process of dolomite.
PL
Przedstawiono wyniki badań procesu granulacji mączki dolomitowej z dodatkiem surowców pochodzenia organicznego, w tym biomasy odpadowej. Zbadano wpływ takiego rodzaju dodatku na wytrzymałość powstającego w procesie granulatu. Oceniono jakość wytworzonych produktów oraz przebieg procesu aglomeracji na podstawie wyników analizy sitowej oraz badania wytrzymałości mechanicznej granul na zgniatanie.
EN
The results of the granulation process of dolomite flour with the addition of organic raw materials, including waste biomass, are presented. The influence of this type of additive on the strength of the granulate produced in the process was investigated. The quality of the manufactured products and the course of the agglomeration process were evaluated on the basis of the results of the sieve analysis and the mechanical strength test of the granules.
EN
Rock and gas outburst is a phenomenon in which fragmented rock material is transported deep into a pit. The transport of rock material by gas is a two-phase process. The article deals with the fluidisation of rock material. Considerations on the fluidisation phenomenon were carried out, and experiments were performed to help clarify whether the fluidisation of dolomite is possible. In the last chapter, a discussion was carried out, and the results obtained were analysed regarding the possibility of occurrence in mine conditions.
4
Content available remote Wpływ roztworów lignosulfonianów na granulację mączki dolomitowej
PL
Przedstawiono wyniki badań procesu granulacji mączki dolomitowej z zastosowaniem wody oraz roztworów lignosulfonianów sodu i wapnia jako cieczy zwilżającej. Zbadano wpływ poszczególnych parametrów granulacji na przebieg procesu oraz właściwości fizykochemiczne otrzymanych granulatów. Oceny jakości wytworzonych produktów, jak i przebiegu procesu dokonano na podstawie wyników analizy sitowej oraz badania wytrzymałości mechanicznej na zgniatanie.
EN
Dolomite was moistened with aq. solns. of Na or Ca lignosulfonate (concs. 1−30% by mass) and granulated in a disc granulator for 1−60 min. The sieve anal. and the mech. strength tests for crushing of granules were performed. Higher values of crushing strength were obtained in the case of granulation of dolomite with the use of Na lignosulfonate.
PL
Przedstawiono ocenę zagrożenia bezpieczeństwa procesowego wytwarzania i przechowywania nawozów o wysokiej zawartości dolomitu z dodatkiem azotanu(V) amonu. Do mieszanek nawozowych zastosowano dodatek lignosulfonianu sodu lub wapnia, który miał na celu ułatwienie i usprawnienie procesu granulacji. Obydwa dodatki silnie zwiększały zagrożenie bezpieczeństwa wytwarzania i pozostałych operacji z mieszankami zawierającymi azotan(V) amonu. Wysoka zawartość dolomitu nie niwelowała niekorzystnego działania lignosulfonianu sodu i wapnia. Badania wykonano metodą analizy DTA/TG.
EN
Na or Ca lignosulfonate in an amt. of 3.2 and 3.0% by mass, resp., was added to the dolomite mixts. with NH₄NO₃ and studied by DTA/TG. Both additives significantly increased the safety risk during the production and storage of fertilizers with mixts. contg. NH₄NO₃. The high content of dolomite did not eliminate the adverse effects of Na and Ca lignosulfonate.
EN
The phosphate rock flotatio n test was carried out using Escherichia coli E. coli ) as a depressant of dolomite. The results showed that E. coli had a great selective depression on dolomite during flotation. With E. coli as a depressant of dolomite, a useful beneficiation index of phosphorus concentrate with P2O5 grade of more than 30% and MgO content less than 1.2% can be obtained by closed circuit of one stage roughing and one stage cleaning. Furthermore, the depression mechanism of E. coli was studied by ad sorption experiments, infrared spectrum, and zeta potential. This study shows that the adsorption ability of E. coli onto dolomite is stronger than that of collophanite. When the pH is greater than 6, E. coli are chemically adsorbed on the surface of the c ollophanite and dolomite,which also increases the negative charge on the surface of the two minerals. The selective adsorption of E. coli cells to dolomite was best when the pH value is about 7.8.
EN
Collophanite in south China generally has a high MgO level, which negatively impacts wet-process phosphoric acid production and cannot be utilized directly. A novel mixed fatty acid soap (GSWF01) was employed as a collector for dolomite. A single reverse flotation experiment was performed on a dolomitic collophanite from Guizhou, China under different pH and collector dosages. A phosphate concentrate with P2O5 grade of 33.73%, MgO content of 1.07%, MER value (ω(MgO+Al2O3+Fe2O3)/ω(P2O5)) of 4.86% and phosphorus recovery of 91.06% was obtained. The beneficiation indexes of GSWF01 were better than that of sodium oleate (NaOL). The adsorption behavior and mechanism of GSWF01 on dolomite surface were investigated using quartz crystal microbalance with dissipation (QCM-D), atomic force microscope (AFM), infrared spectrometer (IR), and zeta potentiometer. The results revealed that GSWF01 chemically reacted with metal ions (Ca2+, Mg2+, etc.) on the surface of dolomite to generate fatty acid salt precipitation (chemisorption). The adsorbed layer transitioned from dense to loose in two stages, resulting in a stable double-layer adsorption structure. Moreover, in a weak acidic solution environment, physical adsorption of fatty acid molecules (RCOOH ((aq)) and fatty acid ion-molecular association compounds (RCOOH• RCOO-) generated by hydrolysis can also occur on the dolomite surface. These are the main reasons for the hydrophobic floating of dolomite. This is of great significance to the development of a novel high-efficiency dolomite collector and the enhancement of flotation process for carbonate collophanite.
EN
The reverse anionic flotation is commonly used to upgrade the mid-low grade phosphate ore in China. The mineral characterization of raw ore shows that carbonate and phosphate minerals combined with fine intergrowth, difficulty in upgrading. Flotation using nanobubbles (NBs) can significantly enhance the flotation efficiency of fine particles of minerals. To research the effect of NBs on the flotation process of this phosphate ore, two flotation tests with and without NBs were compared. The results show that the MgO removal had an increment of 10% in the case of NBs flotation versus conventional flotation in the approximate grade and recovery of P2O5. The foam product of NBs flotation had smaller dimensions than the conventional flotation. NBs enhanced the contact angle on dolomite surface from 45.8° to 64.5°, and increases the d50 of dolomite from 20.49 µm to 30.43 µm.
EN
For a low grade dolomite type fluorite ore in the Hebei province, it was observed that the depressant CK102, a mixture of sulfuric acid, sodium silicate and aluminum sulfate, can effectively inhibit the gangue mineral dolomite in the flotation of fluorite. However, the inhibition mechanism of the depressant is still unclear. In this paper, the flotation separation performance and underlying mechanism of CK102 inhibiting dolomite were investigated through mineral flotation tests, adsorption measurements, infrared spectroscopy, and X-ray photoelectron spectroscopy (XPS). The flotation results showed that the inhibition effect of CK102 on dolomite flotation was much more remarkable than that of fluorite flotation under optimum conditions. Adsorption measurements revealed that there was competitive adsorption between the depressant and collector and that the adsorption of the depressant CK102 prevented the collector modified sodium oleate from adsorbing onto the surface of minerals. The FT-IR and XPS results showed that the co-oxygen cross-linked component of the depressant CK102 chemisorbed on the surface of dolomite; the CaSiO3 precipitation was generated from the reaction of CK102 with Ca2+ groups on the surface of the dolomite; Al2MgO8Si2 precipitation was also generated from Mg2+ reacting with the sodium silicate and aluminum sulfate of CK102. The above adsorptions and reactions enhanced the hydrophilicity of the dolomite surface and the dolomite was effectively depressed.
EN
The presence of Fe and Al atoms in large quantities in phosphate ores can significantly affect the surface properties of the minerals during flotation. In this study, the effects of Fe/Al impurities on the adsorption of H2O molecules on dolomite, including the density of states (DOS), Mulliken bond group values, and charge groups, were investigated and the adsorption energy was analyzed using density functional theory. The results show that the adsorption of H2O molecules on perfect and Fe/Al-substituted dolomites is weak chemisorption, and the Fe and Al impurities weaken and enhance the adsorption capacity of H2O molecules, respectively. Therefore, the hydrophilicity of the dolomite surface increases in the following order: Fe-substituted dolomite < perfect dolomite < Al-substituted dolomite. The Mulliken charge and bond group analysis shows that the adsorption of H2O molecules on dolomite is primarily through the interaction between Ow and Ca atoms, where the d orbitals of Ca atoms provide charges for Ow atoms to form ionic bonds, which related to the poor electronegativity of Ca atoms and their weak valence electron binding ability. The DOS analysis shows that, during the adsorption of H2O molecules on dolomite, Mg and Al atoms have less influence on the dolomite surface, whereas Fe and Ca atoms undergo competitive adsorption, which inhibits the interaction between Ca atoms and H2O molecules on the dolomite surface.
EN
Geopolymer is widely studied nowadays in various scope of studies. Some of the ongoing studies are the study of the various materials towards the geopolymer strength produced. Meanwhile, some of the studies focus on the mixing of the geopolymer itself. This paper discussed the phase analysis of metakaolin/dolomite geopolymer for different solid to the liquid ratio which was, 0.4, 0.6, 0.8, and 1.0, and the properties that affected the geopolymer based on the phases. The constant parameters in this study were the percentage of metakaolin and dolomite used. The metakaolin used was 80% meanwhile dolomite usage was 20%. Besides that, the molarity of NaOH used is 10M and the alkaline activator ratio used is 2.0. All the samples were tested at 28 days of curing. The results show that the 0.8 solid to the liquid ratio used gave better properties compare to other solid to liquid ratio. The phases analyzed were quartz, sillimanite, mullite, and faujasite. The 0.8 S/L ratio shows the better properties compared to others by the test of phase analysis, compressive strength morphology analysis, and functional group analysis.
EN
In September2009, gas and rock were ejected from the roof of the excavation at the Rudna copper mine of KGHM Polska Miedź S.A. The ejection occurred as a result of an unsealing of a small gas trap locateda few metres above the roof of the excavation within the dolomites of the first Zechstein cyclothem (PZ1). In order to identify the nature of the reservoir rock for natural gas, microscopic observations and X-ray microtomography were performed and compared with the results of the acoustic anisotropy tests. The obtained results indicate that, based on well-recognized petrological rocks, the results of acoustic anisotropy can be successfully applied as diagnostic for the recognition of rocks of various structures, textures and porosities.
EN
Reverse flotation of collophanite at natural pH could significantly decrease the cost of pH regulators. In this study, isooctyl polyoxyethylene ether phosphate (AEP) was tested as a new surfactant in the reverse flotation of collophanite. Micro-flotation tests were conducted, and the adsorption mechanism of the new collector was analysed using X-ray photoelectron spectroscopy (XPS) and zeta potential analyses. The results of the flotation tests demonstrated that AEP could enable dolomite to float under natural pH (pH=7.2) and showed profound selectivity towards dolomite as opposed to fluorapatite. Based on the zeta potential and XPS results, the adsorption phenomena are mainly attributed to calcium active sites on both mineral surfaces. Dolomite possesses more magnesium active sites than fluorapatite, which tend to reinforce the interaction effect between AEP and dolomite. Furthermore, when compared to CO32- ions on the dolomite surface, PO43- ions on the fluorapatite surface tend to exhibit a stronger hindrance to the adsorption of AEP on the fluorapatite surface. This is attributed to their larger volumes and more charges on their surfaces, thereby causing a floatability difference between the two minerals.
EN
In this paper, polyaspartic acid (PASP) was exploited as a novel dolomite depressant for flotation separation of apatite and dolomite. A series of tests with Zeta potential, FTIR and XPS were used to reveal the inhibitory mechanism of PASP on dolomite. The microflotation test illustrated that PASP has a strong inhibitory impact on dolomite, and little effect on the floatability of apatite in the pH range of 9-11. When using 2.7 Mg/L PASP as the depressant under sodium oleate (NaOl) system, the flotation recovery of dolomite dropped dramatically to 9.95%, and the recovery of apatite remained at about 88.27% at pH 10. Both dolomite and apatite have calcium ion on the surface. The calcium ion on the surface of apatite were strongly inhibited and repelled by the localized anions, while the important role on the surface of dolomite was positively charged magnesium ion and localized calcium species. PASP could ionize carboxylate ion under alkaline conditions, which could chemically chelate with the exposed metal ion and be adsorbed on the surface of dolomite. And then prevent the further adsorption of NaOl onto dolomite, which greatly weaken the floatability of dolomite and enhanced the flotation separation of the two minerals.
EN
With high-grade apatite resources exhausted and economic development, enhancing the apatite quality from calcium gangue such as dolomite has a great significance for production. However, it is difficult to separate apatite from dolomite effectively due to the similar surface properties. In this study, the N-carboxybutyl chitosan (CBC) was tested as a potential selective depressant to separate apatite from dolomite in the sodium oleate (NaOL). Flotation results of single mineral and artificially mixed mineral confirmed the selective depression effect of CBC. The depression mechanism of CBC was investigated using wettability analysis, Fourier Transform Infrared (FTIR), and X-ray Photoelectron Spectroscopy (XPS) analyses. The results indicated that the CBC adsorption quantity and intensity on the dolomite surface more than that on the apatite surface, which was due to CBC absorbed on apatite surface by hydrogen bonding, while absorbed on dolomite surface mainly through chemical chelating between Ca on the mineral surface and -COO- on the depressant. These adsorption differences led to the flotation separation of the two minerals.
PL
W artykule przedstawiono wyniki badań porowatości skał, pochodzących z Legnicko-Głogowskiego Okręgu Miedziowego, określonych dwiema metodami: densymetryczną oraz punktową analizą mikroskopową. Do określenia porowatości sposobem densymetrycznym wykorzystano metody piknometrii helowej oraz quasicieczowej a także autorski analizator do rozdrobnienia skał. Porowatość metodą punktowej analizy mikroskopowej zbadana została przy pomocy mikroskopu polaryzacyjnego AXIOPLAN ze sterowanym komputerowo stolikiem mechanicznym XYZ. Analizom poddano 20 próbek dolomitu. Dla wszystkich próbek wyznaczona została porowatość całkowita na dwa sposoby. Każda z próbek w metodzie densymetrycznej uzyskała niższy wynik porowatości całkowitej. Średnia porowatość wyznaczona metodą densymetryczną wyniosła niespełna 3%, zaś w punktowej analizie mikroskopowej wynik ten był na poziomie 8,2%.
XX
The article presents the results of research of porosity of rocks from the Legnica-Głogów Copper District, determined by two methods: densimetric and point microscopic analysis. The helium and quasi-liquid pycnometry methods were used to determine the porosity using the densimetric method, as well as the author’s analyser for rock fragmentation. The porosity was determined by point microscopic analysis using an AXIOPLAN polarizing microscope with a computer-controlled XYZ mechanical table. 20 samples of dolomite were analyzed. For all samples, the total porosity were determined in two ways. Each of the samples in the densimetric method obtained a lower total porosity result. The average porosity determined by the densimetric method was less than 3.0%, while in the point microscopic analysis, this result was at the level of 8.2%.
EN
Dolomite is the main impurity mineral in magnesite ore, affecting the quality of magnesite products. This study proposed a selective leaching process to reduce the calcium content from the magnesite flotation concentrate using hydrochloride acid (HCl). Laboratory scale tests were conducted to explore the influence of operation factors including HCl concentration, leaching temperature and time, stirring speed on the leaching recovery. The results showed that leaching recovery of CaO and MgO increased with increasing HCl concentration, temperature and time. The CaO leaching recovery is always significantly higher than that of MgO, indicating a good selectivity of HCl to leach dolomite from magnesite. The leaching kinetics of both dolomite and magnesite follow the Avrami model and are diffusion controlled, with an activation energy of 43±}1 kJ×mol-1 and 25±}4 kJ×mol-1, respectively.
EN
In this study, the neural model for modeling of oil agglomeration of dolomite in the presence of anionic and cationic surfactants (sodium oleate and dodecylammonium hydrochloride) was implemented. The effect of surfactants concentration, oil dosage, time of mixing, pH, and mixing speed of the impeller in the process recovery were investigated using Radial Basis Function Neural Network (RBFNN). A significant problem in this modeling, was the selection of the structure of the neural network. In algorithms based on the RBFNN, the issue mentioned relates to the number of nodes in the determination of the hidden layer. Also, the distribution of functions in data space is significant. In the proposed solution, at this stage of the neural model design, the Growing Neural Gas Network (GNGN) was implemented. Such a procedure introduced automation of the calculation process. The centers were obtained from the GNGN and the structure (number of radial neurons) can be approximated based on a simple searching algorithm. The idea of the data calculations was implemented as an original algorithm that can be easily transferred to Matlab, Python, or Octave software. The values predicted from the neural networks model were in good agreement with the experimental data. Thus, the RBFNN-GNGN model used in this study, can be employed as a reliable and accurate method to predict, and in the future to optimize the performance of oil agglomeration process.
EN
Sulfuric acid (H2SO4) is a specific depressor for apatite rather than for dolomite. The H2SO4treated dolomite can still be floated effectively by oleate. However, the role of H2SO4 in the adsorption of oleate onto dolomite surface remains unclear. In this work, density functional theory calculations were conducted to probe the interactions among sulfate anion (SO42−), oleate anion and the dolomite surface. The adsorption behaviors of SO42− anion onto the perfect and CO3-defect dolomite surfaces were compared. Such results show that SO42−anion could only adsorb onto the defective dolomite surface, where it bonded with a Ca atom. The remaining Ca and Mg atoms at the defect site could further react with the oleate anion, generating new Ca/Mg–O ionic bond. In this regard, oleate and SO42−anions may both present on the dolomite surface. This phenomenon accounts for the flotation of H2SO4-treated dolomite.
PL
Województwo świętokrzyskie znane jest ze swoich złóż kruszyw. Jednym z wyróżniających się zakładów górniczych jest ten działający od wielu lat w Budach. Tym razem po kopalni oprowadzi nas jej kierownik Marek Zając, który opowie nie tylko o prehistorycznej przeszłości tych terenów, ale także o tym, jakie są plany firmy na przyszłość.
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