The present disclosure concerns expandable silica particles having a coating comprising talc powder and kaolin powder provided on the outer surface of the expandable silica particle and expandable and expanded silica particles comprising silica fume and/or ultrafine quartz silica sand beneath the surface of the particles. Methods for producing expandable and expanded silica particles are disclosed, including a method using a vibration plate and a furnace having a vibration plate for carrying out that method. The expanded silica particles have high compressive strength, substantially uniform cell size and distribution, low water absorption, and low porosity on the outer surface. They are useful as a filler in matrix materials, like concrete or epoxy, as insulation material with various binder materials, and as water filtration medium.

The present disclosure concerns expandable silica particles having a coating comprising talc powder and kaolin powder provided on the outer surface of the expandable silica particle and expandable and expanded silica particles comprising silica fume and/or ultrafine quartz silica sand beneath the surface of the particles. Methods for producing expandable and expanded silica particles are disclosed, including a method using a vibration plate and a furnace having a vibration plate for carrying out that method. The expanded silica particles have high compressive strength, substantially uniform cell size and distribution, low water absorption, and low porosity on the outer surface. They are useful as a filler in matrix materials, like concrete or epoxy, as insulation material with various binder materials, and as water filtration medium.

A device for producing expanded granulated material from mineral material in the form of grains of sand with an expanding agent includes a furnace with a furnace shaft, having an upper end and a lower end. A conveying section extends between the two ends and passes through a number of heating zones arranged separately from one another in a conveying direction. The device also includes at least one feeder in order to charge at least the unexpanded material into the furnace shaft at one of the two ends in the direction of the other of the two ends. At least one directing element is at least partly arranged in the furnace shaft and forms a gap with an inner wall of the furnace shaft, at least in the region of one of the two ends. The at least one feeder is designed for charging the material into the gap.

A device for producing expanded granulated material from mineral material in the form of grains of sand with an expanding agent includes a furnace with a furnace shaft, having an upper end and a lower end. A conveying section extends between the two ends and passes through a number of heating zones arranged separately from one another in a conveying direction. The device also includes at least one feeder in order to charge at least the unexpanded material into the furnace shaft at one of the two ends in the direction of the other of the two ends. At least one directing element is at least partly arranged in the furnace shaft and forms a gap with an inner wall of the furnace shaft, at least in the region of one of the two ends. The at least one feeder is designed for charging the material into the gap.

A bitumen product including bitumen and a mineral filler. In order to reduce the specific weight of the bitumen product while allowing sufficient scaling effect, the mineral filler contains expanded perlite grains, the expanded perlite grains having a closed-cell surface, and the expanded perlite grains having a closed-cell surface are not ground.

A bitumen product including bitumen and a mineral filler. In order to reduce the specific weight of the bitumen product while allowing sufficient scaling effect, the mineral filler contains expanded perlite grains, the expanded perlite grains having a closed-cell surface, and the expanded perlite grains having a closed-cell surface are not ground.

The invention relates to a method for producing an expanded granulate from sand grain-shaped mineral material (1) with a propellant, wherein the material (1) is fed into a vertically upright furnace (2) from above and said material (1) falls along a drop section (4) through multiple heating zones (5) in a furnace shaft (3) of the furnace (2), wherein each heating zone (5) is heatable using at least one independently controllable heating element (6), and the material (1) is heated to a critical temperature at which the surfaces (7) of the sand grains (15) plasticize and the sand grains (15) are expanded by the propellant. In order to enable setting a closed surface of the expanded granulate in a purposeful fashion, it is provided in accordance with the invention that upon detection of a first reduction in the temperature of the material (1) between two successive positions (9) along the drop section (4) the heating elements (6) are controlled along the remaining drop section (4) depending on the critical temperature.

The invention relates to a method for producing an expanded granulate from sand grain-shaped mineral material (1) with a propellant, wherein the material (1) is fed into a vertically upright furnace (2) from above and said material (1) falls along a drop section (4) through multiple heating zones (5) in a furnace shaft (3) of the furnace (2), wherein each heating zone (5) is heatable using at least one independently controllable heating element (6), and the material (1) is heated to a critical temperature at which the surfaces (7) of the sand grains (15) plasticize and the sand grains (15) are expanded by the propellant. In order to enable setting a closed surface of the expanded granulate in a purposeful fashion, it is provided in accordance with the invention that upon detection of a first reduction in the temperature of the material (1) between two successive positions (9) along the drop section (4) the heating elements (6) are controlled along the remaining drop section (4) depending on the critical temperature.

An apparatus for producing a bloated mineral granulate with a heated processing channel (1) for the mineral granulate fed to a conveying flow (13), wherein an inflow opening (4) is provided in the processing channel (1) for forming a granulate-free laminar flow (5) running along the inner wall of the processing channel, is described.

In order to design a device of the type described above in such a way that a continuous, qualitatively controllable production process is achieved, it is proposed in that the processing channel (1) comprises two channel sections (16), (17) with differing cross-sections, wherein the channel section (16) with a smaller cross-section projects into the channel section (17) with a larger cross-section, forming the inflow opening (4), and wherein the channel section (16) with a smaller cross-section is enclosed by the channel section (17) with a larger cross-section in such a way that an inflow opening (4) is formed completely around the projecting region of the channel section (16) with a smaller cross-section.

A device for producing expanded granulated material from grains of sand with an expanding agent includes a furnace with a furnace shaft, which has upper and lower ends. A conveying section extends between the ends and passes through separately-arranged heating zones in a conveying direction. At least one feeder charges at least the unexpanded material into the furnace shaft at one end toward the other end. At least one rotatable shaft insert is arranged at least in sections in the furnace shaft and has at least one scraper blade forming with an inner wall of the furnace shaft at least one gap having a gap width and being designed, during rotation of the at least one shaft insert in an operating state of the device, to remove caking on the inner wall at least in sections if a thickness of the caking is greater than the respective gap width.