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Ankerite

About: Ankerite is a research topic. Over the lifetime, 859 publications have been published within this topic receiving 23960 citations.


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Journal ArticleDOI
TL;DR: In this paper , the mineralogical and geochemical characteristics of the Late Triassic coals from the Coc Sau open-pit mine, Cam Pha Coalfield (Quang Ninh Province, Northeastern Vietnam) using powder X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), inductively coupled plasma atomic-emission spectrometry (ICP-AES), and inductive coupled plasma mass spectrometric (ICP-MS) were investigated.

4 citations

Proceedings ArticleDOI
21 Feb 2022
TL;DR: In this article , a 1M solution of diammonium phosphate (DAP) for 3 days at room temperature conditions was used to strengthen carbonate rocks via the transformation of calcite into the harder hydroxyapatite mineral.
Abstract: Hydraulic fracturing operations involve generating conductive pathways in low permeability formations to maximize hydrocarbons production. One of the main challenges is maintaining fracture conductivity under high closure stresses, especially in soft formations. However, long–term fracture conductivity can be sustained through fracture surface hardness improvement. This research targets the strengthening of carbonate rocks via the transformation of calcite into the harder hydroxyapatite mineral. In this study, limestone, chalk, and dolomite rock specimens were treated with 1M solution of diammonium phosphate (DAP) for 3 days at room temperature conditions. Rock samples’ hardness was measured by indentation (Brinell hardness) technique before/after the treatment to assess the strengthening effect of DAP. The changes in the mineralogy in treated samples were studied by SEM-EDS technique. The formation of phosphate minerals was achieved in treated samples, and they were clearly seen in the SEM images. The results have shown that both limestone and chalk samples reacted strongly with DAP solution, which was expressed in terms of rich abundance in newly formed minerals inside rock specimens. The reaction between dolomite and DAP solution was observed to be weak which resulted in generation of isolated phosphate minerals. The formed minerals were identified as hydroxyapatite (5 hardness in the Mohs scale) after comparing their morphology with other phosphate minerals reported in the literature. Treatment of the rocks by DAP solution resulted in improvement of their strength. The Brinell hardness of the chalk specimen was increased by 30% after the treatment, whereas in the case of the limestone sample, a 13% increment in hardness was achieved. The proposed carbonate rock strengthening technique can be applied in hydraulic fracturing It is intended to solve common soft formations problems (e.g., asperities failure, proppant embedment) causing acid/propped fractures’ conductivity reduction.

4 citations

Journal ArticleDOI
K. C. Dunham1
01 Dec 1984
TL;DR: In the case of the West Cumbria Hematite ores as discussed by the authors, the ores have been wrongly classified as of Bilbao type by United Nations investigators (United Nations 1970); this type is derived from siderite/ankerite protores by oxidation.
Abstract: (Resume of an evening lecture given during the field meeting on the West Cumberland Hematite ore field, 15th – 17th July, 1983) West Cumbria and Furness have provided about 250 million tons of high-grade iron ore since mining began in earnest about the middle of last century. Iron contents in the range 50–60 per cent, with P2O5 less than 0.02 and S less than 0.06 have been normal as a result of the very simple mineralogy of the deposits, composed of massive and botryoidal hematite with dolomite and quartz as the only gangue minerals of quantitative importance. In a few places, a little chalcopyrite occurred as an early phase, while in others, small amounts of blue fluorite and of baryte were associated with specularite in late cavities. As J. D. Kendall (1881–82) first conclusively demonstrated, most orebodies were emplaced by metasomatism of limestone, in the course of which fossils were replaced molecule by molecule by hematite or quartz, and layers of chert nodules were preserved in situ in the orebodies, particularly those, like the example seen at Florence Mine, having the form of flats. The ores have been wrongly classified as of Bilbao type by United Nations investigators (United Nations 1970); this type is derived from siderite/ankerite protores by oxidation; careful determination of large numbers of carbonates has failed to show any evidence for such protores in West and South Cumbria. The hematite is unquestionably a primary mineral; in this respect the origin of the ores is radically different …

4 citations

Journal ArticleDOI
TL;DR: The shell substance of the non-marine lamellibranchs from a band in the lower similis-pulchra zone of Lancashire is shown to be ankerite.
Abstract: "The shell substance of the non-marine lamellibranchs from a band in the lower similis-pulchra zone of Lancashire is shown to be ankerite. The same mineral also forms pockets inside certain of the shells, the pockets being developed most frequently in the stratigraphically uppermost part of the spaces between the valves. It is considered that the ankerite in the pockets has occupied spaces left by shrinkage of the original mud-filling of the shells. Chemical analyses, specific gravity, and optical properties of the ankerite are given; its composition closely approximates to (Mg 2 Fe) Ca 3 (CO 3 ) 6 ."

4 citations

Journal Article
TL;DR: In this article, the process of mineral corrosion, dissolution and precipitiation and the permeability variation of reservoir rocks after CO2 injection was studied in detail through core flooding laboratory experiment carried out under simulated reservoir conditions (100℃ and 24 MPa).
Abstract: In order to explore the short-term changes in reservoir lithology and physical properties,the process of mineral corrosion,dissolution and precipitiation and the permeability variation of reservoir rocks after CO2 injection,the interation process between CO2-saturated rocks and formation water was studied in detail through core flooding laboratory experiment carried out under simulated reservoir conditions(100℃ and 24 MPa).Changes in ion compositions of the reaction solution in pre-and post-CO2-flooding experiments as well as core scanning electron microscopic and whole-rock X-ray diffraction(XRD) analyses showed that dissolution and corrosion phenomena of carbonate minerals can be observed after the experiment,among which calcite dissolution is the strongest,followed by dawsonite,while ankerite the weakest.The concentration of K+ in the reaction solution varies mainly due to the dissolution of detrital K-feldspar grains.A small amount of kaolinite and intermediate products were generated after the experiment.The composition of intermediate products is mainly composed of C,O,Na,Cl,Al and Si,which have a trend to change into carbonate minerals.New minerals(Kaolinite and intermediate products) and the particles released by the dissolution of the carbonate cement were moved to pore throats and blocked the path of pore,which was the main reason that caused the core permeability reduction.The experiment results have reproduced the short-term process of corrosion of feldspar and dissolution of carbonate minerals as well as precipitation of new minerals after CO2 injection,revealed reasons of permeability variation,and provided geochemical evidence for CO2 trapping mechanisms underground.

4 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202332
202270
202140
202027
201946
201842