Скачать или смотреть Comin in Heavy! The Arthur M Anderson Arriving Duluth with a cargo of limestone April 16, 2021

Trip # 4 for the Anderson to Duluth ! The more the better in my opinion 😁.
This is their 1st trip arriving with cargo, the stone yards are back open! Bringing in limestone for the mines to use in their taconite process.
They arrived 4/16/2021 9:45:00 AM, sailed way up the river the to C Reiss dock to discharge the limestone. After discharging, heading down river to the CN dock to load iron ore. They will spend a total of 30.4 hours in port. Of those hours, they spent 9.3 hours discharging the stone at C. Reiss, 15 hours loading at CN.

Limestone and Dolomite and their Use in Iron and Steel Plant

Limestone is a naturally occurring mineral. The term limestone is applied to any calcareous sedimentary rock consisting essentially of calcium carbonate (CaCO3) in the form of the mineral calcite. It forms predominantly on the sea floor where material rich in calcium carbonate (‘calcareous’ material) accumulates. This calcareous material can be organic, chemical or detrital in origin.

Types of limestone include (i) bituminous limestone, (ii) carboniferous limestone, (iii) coquina which is a sedimentary rock composed mostly of fragments of shells, (iv) coral rag, (v) chalk which is a soft, white, porous sedimentary rock made of calcium carbonate, (vi) fossiliferous limestone, (vii) lithographic limestone, (viii) oolite which is a sedimentary rock formed from ooids, (viii) rag-stone which represents work done with stones that are quarried in thin pieces, (ix) shelly limestone, (x) travertine which is a form of limestone deposited by mineral springs, (xi) marl, and (xii) tufa which is a porous limestone rock formed when carbonate minerals precipitate out of ambient temperature water. Limestones altered by dynamic or contact metamorphism become coarsely crystalline and are referred to as ‘marbles’ and ‘crystalline limestones’. The limestone which is used by iron and steel industry in bulk quantity is a bedded type sedimentary limestone.

The two most important constituents are calcite and dolomite. Limestone frequently contains magnesium carbonate, either as dolomite CaCO3.Mg CO3 or magnesite (MgCO3) mixed with calcite. Such rocks are termed as ‘dolomitic’ or ‘magnesian’ limestone. The mineral calcite is normally white or gray but impurities either within or between the calcite particles can make a limestone brown, yellow, bluish gray, pink, red, green, gray, or even black. Calcite has a specific gravity of 2.710 and hardness of 3 on the Mohs scale. It breaks readily into small blocks. The texture of limestone is clastic or non-clastic. If it is clastic or bioclastic then grains and / or broken or whole shell fragments are visible. If it is non-clastic / chemical then it is crystalline and no clasts are visible. The grain size is variable and can consist of clasts of all sizes. Limestones contain at least a few percent other materials. These can be small particles of quartz, feldspar, clay minerals, pyrite, siderite, and other minerals. It can also contain large nodules of chert, pyrite, or siderite. The calcium carbonate content of limestone gives it a property which is frequently used in rock identification. It effervesces in contact with a cold solution of 5 % hydrochloric (HCl) acid.

Limestone chemical purity has a direct effect on the chemical purity of lime which is produced by the calcining of limestone. There are some possibilities for removing the impurities when they are principally located around the stone, but otherwise further processing steps keep the impurities embedded with the finished product. The main impurities in limestone are in the form of clay, silt, or sand, or sometime organic matter. The calcium (Ca) and carbon dioxide (CO2) constitute the calcium carbonate (CaCO3), with impurities including magnesium (Mg), silicon (Si), aluminum (Al), sulphur (S), phosphorus (P), potassium (K), and sodium (Na). A metallurgical grade of limestone needs a minimum of 95 % carbonates (Ca and Mg).

Limestone is normally extracted from open-air quarries rather than underground mines, because of an outcrop of quality products (Fig 1) in most of the deposits. Nevertheless, it is common that good chemical quality occurs only in certain layers, raising the need to select and separate aggregate types from the chemical stone. Limestone extraction is done by blasting, followed by crushing and screening. Depending on the chemical characteristics, limestone can be washed to remove the surrounding impurities such as clays. Calibrated stones size (Fig 1) of the lime stone depends on its further use. Finer-sized limestone can be used partially as raw material for self-fluxing sinters.

If you are interested in the complete article: https://www.ispatguru.com/limestone-a...