Thermodynamic properties of hematite — ilmenite
AbstractA solution model is developed for rhombohedral oxide solid solutions having compositions within the ternary system ilmenite [(Fe2+sTi4+1−s)A (Fe2+1−sTi4+s)B O3]-geikielite [(Mg2+tTi4+1−t)A (Mg2+1−tTi4+t)B O3]-hematite [(Fe3+)A (Fe3+)B O3]. The model incorporates an expression for the configurational entropy of solution, which accounts for …
ILMAT: An Excel worksheet for ilmenite-magnetite
Magnetite-ilmenite geothermometer (TIlm-Mag): Some samples of massive ore ( Fig. 3J; sample NW-84) and vein ore ( Fig. 3L; 14NW-73), contain primary magnetite and coexisting ilmenite lamellae that ...
Phase relations in the ilmenite-hematite solid solution.
The R3 to R3c cation ordering phase transition in the ilmenite (FeTiO3)-hematite (Fe2O3) solid solution has been investigated using in-situ time-of-flight neutron powder diffraction.
ILMENITE-HEMATITE-MAGNETITE RELATIONS IN
The great predominance of hematite over ilmenite in the intergrowths indicates that the original solid solution was very much richer in hema- tite than in ilmenite.
The role of hematite–ilmenite solid solution in the …
For example, Kletetschka and Stout (1998) found a region (Fig. 1) where the magnetization contrast was mainly due to RM carried by HISS mineralogy. In most cases, induced magnetization contrasts reflect the relative proportions of magnetite, which has a mass susceptibility three to four orders of magnitude larger than hematite and most of the other …
Nature and origin of lamellar magnetism in the hematite-ilmenite …
Atomic-scale simulations of an R3̅ ilmenite lamella in a CAF hematite host, based on empirical cation-cation and spin-spin pair interaction parameters, show that contacts of the lamella are occupied by "contact layers" with a hybrid composition of Fe ions intermediate between Fe 2+-rich layers in ilmenite and Fe 3+-rich layers in hematite.
Lamellar magnetism in the haematite–ilmenite series as an
Haemo-ilmenite samples without coexisting magnetite have natural remanent magnetization to magnetic saturation ratios of only ∼ 2.5%, showing that the haematite …
Ilmenite | Physical
Intergrowths with hematite or magnetite are common, and ilmenite can be mistaken for these minerals because of its opaque, metallic, gray-black color. Unlike magnetite, however, ilmenite is nonmagnetic or very …
Magnetization of exsolution intergrowths of …
Contact layers at hematite-ilmenite interfaces may help stabilize the magnetism so that a component of it may persist with a large magnetization over long time periods. [75] Ilm 98 shows little or no superparamagnetism and …
Hematite (The Bloodstone Ore)
It is sometimes also labeled as specular hematite or micaceous hematite. Titano-Hematite. Titano-hematite is a titanium-rich variant, mixture of hematite and ilmenite. Based on the strict IMA classification, titanohematite is not a valid mineral. However, hematite-ilmenite solid solutions (HISS) are quite widespread in some rocks.
Fe–Mg and Fe–Mn interdiffusion in ilmenite with …
The Fe–Mg and Fe–Mn interdiffusion coefficients for ilmenite have been determined as a function of temperature and crystallographic orientation. Diffusion annealing experiments were conducted at 1.5 GPa between 800 and 1100 $$^{circ }hbox {C}$$ ∘ C . For Fe–Mg interdiffusion, each diffusion couple consisted of an ilmenite polycrystal and an …
Effects of Ilmenite Ore on Phase Development of Hematite …
The effects of adding 5 to 25 wt pct of ilmenite ore to hematite ore sinter were investigated employing a horizontal tube furnace to clarify the phase development. The temperature was raised nonisothermally at 10 °C/min to 1150 °C in an Ar atmosphere. When the target temperature was reached, 1 L/min of air was injected to allow combustion of the carbon …
Geochemistry of magnetite and hematite from unmineralized …
Petrographic evidence such as 1) undeveloped crystal faces of magnetite and hematite, 2) irregular boundaries of the iron oxides, 3) ilmenite replacement by magnetite, and presence of ilmenite and magnetite inclusions in hematite, and 4) hematite pseudomorphs after magnetite reveal that iron oxides in igneous rocks crystallized under ...
Magnetite-rutile symplectite derived from ilmenite …
hematite and ilmenite belong to the trigonal system, they tend to form a coherent interface in solid transformation (Robinson et al. 2002); in contrast, rutile is tetragonal and magnetite cubic, so
Ilmenite
The crystal structure of is identical to hematite. It is compositionally pretty close to hematite as well. The only difference between them is that one Fe atom (in hematite) is replaced by titanium atom (in ilmenite). The chemical formula is FeTiO 3. This is ideal formula which often is pretty close to the reality, but some of the iron may be ...
Magnetization of exsolution intergrowths of …
Magnetite, rutile needles, discrete pyrite and pyrrhotite are also present in AL20c. A late stage alteration with magnetite replacing hematite is commonly associated with sulfides. Magnetite is present also as elongate …
Ilmenite: An ore of titanium | Uses and Properties
With just a glance it can easily be confused with hematite and magnetite. The differentiation is easy. Hematite has a red streak, while ilmenite has a black streak. Magnetite is strongly …
Magnetite-rutile symplectite derived from ilmenite-hematite …
A unique symplectitic intergrowth of magnetite + rutile is hosted by ilmenite in the gabbro of the Xinjie Fe-Ti oxide-bearing, mafic-ultramafic layered intrusion. The crystallization of rutile in the symplectite is probably formed by oxidation of ilmenite-hematite solid solution (Ilm-Hem ss ). Segregation of Fe 3+ in the Ilm-Hem ss at the rutile-host interfaces triggered the …
Spin orientation in solid solution hematite-ilmenite
The spin orientation in synthetic hematite-ilmenite samples and in a sample of natural hematite was studied from room temperature to above the antiferromagnetic-paramagnetic phase transition (the Néel temperature; T N ≈ 600–950 K) by neutron powder diffraction and at room temperature by Möss spectroscopy. The usually assumed …
Ilmenite | Titanium Ore, Iron Ore & Magnetite | Britannica
Ilmenite, iron-black, heavy, metallic oxide mineral, composed of iron and titanium oxide (FeTiO3), that is used as the major source of titanium. It forms solid-solution series with geikielite and pyrophanite in which magnesium and manganese, respectively, replace iron in the crystal structure. ... hematite hematite group (Show more)
Magnetization of exsolution intergrowths of hematite and …
To understand the magnetism and evolution of the exsolution lamellae, the microstructures and nanostructures were studied using scanning electron microscopy and …
Magnetite-rutile symplectite in ilmenite records magma …
The magnetite-rutile symplectite may be used as a unique texture indicator of magma hydration in the evolution history of terrestrial, martian, and lunar magmas. Keywords: Magnetite-rutile …
The Magnetite-series and Ilmenite-series Granitic Rocks
Opaque minerals of common granitic rocks were studied microscopically. The granitoids were divided into (i) a magnetite-bearing magnetite-series and (ii) a magnetite-free ilmenite-series. Each series has the following characteristic assemblages of accessary minerals: Magnetite-series: Magnetite (0.1-2 vol.%), ilmenite, hematite, pyrite, sphene, epidote, high ferric/ferrous …
Magnetite-rutile symplectite in ilmenite records magma …
Here we investigated ilmenitehematite solid solution (Ilm ss) relationships evident in preserved intergrowths of magnetite-rutile and ilmenite-hematite in the gabbro of the Xinjie layered intrusion.
A method of tracing the temperature and oxygen …
HISTORY OF MAGNETITE-ILMENITE GRAINS 1o5 It must also be noted that the ilmenite-hematite contours of the Buddington and Lindsley geothermometer do not diverge very much from the buffer lines. Several authors (e.g. Anderson, Buddington, Dasgupta, and Czamanske--see note by Czamanske and Mih~ilak, 1972, p. 5o7),
Ferromagnetism and exchange bias in compressed …
Therefore, we consider that the compressed ilmenite-hematite solid solution is an additional candidate source of other planetary magnetic anomalies including those in the Moon and Earth. INTRODUCTION Earth's magnetic anomalies are commonly attributed to the presence of magnetite, hematite, titanomagnetite, and pyrrhotite minerals. Magnetite ...
Ilmenite, magnetite, hematite, and copper in lavas of the …
The opaque minerals in ten lava flows of the Keweenawan series of Michigan were studied microscopically by the writer. The basaltic lavas, which range in thickness from 100 to 1,400 feet, contain ilmenite, magnetite, hematite, intergrowths of magnetite-ilmenite and ilmenite-hematite, copper sulfides, native copper, and pyrite.
Ilmenite Fe2+TiO3
Ilmenite Fe2+TiO3 c 2001-2005 Mineral Data Publishing, version 1 Crystal Data: Hexagonal. Point Group: 3. As thick tabular crystals, with dominant base, to rhombohedral, to 25 cm. Skeletal, granular, massive; as lamellar exsolutions in hematite or magnetite. Twinning: Simple on {0001}; lamellar on {1011}.
Ilmenite – Virtual Museum of Molecules and Minerals
Ilmenite may contain significant isomorphic substitutions of Mg2+ and Mn2+ for both Fe2+, and probably forms solid solutions with both geikielite (Mg,Ti)2O3 and pyrophanite (Mn,Ti)2O3 end-members. Ilmenite commonly shows intergrowth with hematite and magnetite. The crystals are totally opaque and appear as thick tabular crystals or anhedral ...
Magnetization of exsolution intergrowths of hematite and ilmenite …
Combined electron microprobe, TEM, and X-ray diffraction (XRD) results indicate that hematite hosts reached a composition approximately ilmenite (Ilm) 14.4, and ilmenite hosts ∼Ilm 98. The bulk of the very stable NRM, which shows thermal unblocking ∼595–620°C, was acquired during final exsolution in the two-phase region canted ...