A bowl mill for producing coarse ground particles has a substantially closed body, a bowl assembly, a plurality of grinding rolls, and a coarse particle transport enabling area. The substantially closed body has an interior area. The bowl assembly includes a rotatable grinding table mounted for rotation in a direction of rotation in the interior area. The grinding table has a grinding surface thereon. The plurality of grinding rolls are positioned proximate the grinding surface. The grinding rolls and the grinding surface define a grinding area therebetween. The coarse particle transport enabling area is located radially outward from the grinding area. The coarse particle transport enabling area is configured to allow the coarse particles to freely exit the grinding area and to mitigate the coarse particles from being circulated back into the grinding area.

The invention relates to a method for preparing and activating a raw material, wherein the raw material is comminuted by means of grinding rollers in a mill-classifier combination, and wherein the mill-classifier combination is set and operated to produce a ground product with a fineness of between D50=3 m and D50=12 m. Here, a part of the grinding product is comminuted by means of the mill-classifier combination to a diameter of <5 m. Subsequently the ground product is subjected to a further classification in an ultrafine grain classifier unit which has a separation threshold in order to separate ultrafine grain with a fineness of <D50=6 m. The invention further relates to an installation configuration for carrying out the method according to the invention.

A vertical roller mill has grinding rollers which roll over a grinding path of a rotatable grinding table, and a surrounding nozzle ring separation area for conveying and separating gas. A coarse fraction of ground material is entrained in gas upwards in ducts from a location that is below, at, or above the nozzle ring separation area and is transported into an entry to a material separator located above the grinding table.

A vertical roller mill has grinding rollers which roll over a grinding path of a rotatable grinding table, and a surrounding nozzle ring separation area for conveying and separating gas. A coarse fraction of ground material is entrained in gas upwards in ducts from a location that is below, at, or above the nozzle ring separation area and is transported into an entry to a material separator located above the grinding table.

A classifier for separating particles is provided. The classifier includes a rotor having a direction of rotation defined by a rotational axis of the rotor, and a plurality of blades disposed on the rotor around the rotational axis. At least one blade of the plurality has a swept orientation in the direction of rotation. The at least one blade is arranged to contact and direct the particles away from the classifier and thereby restrict the particles from concentrating in areas adjacent to the classifier.

A vertical roll mill may include a grinding plate, a grinding roll, a nozzle ring that horizontally surrounds the grinding plate, an air feed apparatus disposed under the nozzle ring, a discharge element disposed below or in a region of the air feed apparatus, and a bypass apparatus disposed in the nozzle ring. The bypass apparatus may form a connection between the nozzle ring and the discharge element. Further, the bypass apparatus can discharge particles that are difficult to grind, for example, ductile particles such as iron particles, from the grinding process. In some examples, the bypass apparatus includes a gas-impermeable outer skin in the region of the air feed apparatus.

A grinding roller is configured so that the fatigue strength of a roller housing can be ensured, and product life can thus be ensured. The grinding roller includes: a roller housing; a roller main body; a pressing plate; a tab hole; and a tab. A line at which fastening stress caused by the pressing plate is concentrated on a base portion of a fixing stopper part of the roller housing and a line at which stress caused by a grinding load received by the roller main body is concentrated on a base portion of the tab hole of the roller housing are disposed in an offset manner so as not to intersect each other.

A method and system for coal ash reclamation from a land fill, the system comprising: a harvester; a screen for screening non-ash material from ash collected by the harvester; a dryer for drying raw ash thereby creating dried coal ash and fine particulate ash; an exhaust pipe to direct the ash to a dust collector; a crusher for crushing the dried ash; a classifier for classifying the crushed dried ash; and a storage container for storage. The method comprising: harvesting raw coal ash from a land fill; screening the raw coal ash to remove oversize materials; drying the screened ash to remove water; crushing the stream of dried ash; classifying the crushed ash into fine particulate ash and large particulate ash, the second stream being directed for further crushing; streams of fine particulate ash being cooled; and storing the fine particulate ash.

An enhanced retractable flow discharge extension is configured for use in a coal pulverizer having a classifier system including a feedpipe to deliver from above raw coal to a pulverizing structure and a classifier cone positioned around the feedpipe to collect oversized coal for the pulverizing structure. The enhanced retractable flow discharge extension is configured to deliver oversized coal to the pulverizing structure and has a conical extension portion having an inlet end configured to be contiguous with the classifier cone outlet, a fixed cylindrical portion having an upper end contiguous with an outlet end of the conical extension portion, a movable cylindrical portion having a circumference larger than a circumference of the fixed cylindrical portion, the movable cylindrical portion being movably attached to the fixed cylindrical portion, and a distal portion movably attached to the movable cylindrical portion, the distal portion having a straight portion and a tapered portion.

The invention relates to a classifier arrangement for a vertical roller mill having at least two classifiers. Each classifier has an active rotor which is rotatable about an axis of rotation. The axis of rotation is aligned at least at an angle of 50 to the vertical. The invention is characterized in that around each classifier a guide vane arrangement is provided at least partially surrounding the said classifier and having at least one guide vane. The guide vane has an open profile towards the axis of rotation. Furthermore, the invention relates to a vertical roller mill having a classifier arrangement according to the invention.