Method for treating granulated blast furnace slag
AssigneeBethlehem Steel Corporation
InventorsKenneth H. Gee, John W. Kreiger
Life of this patent
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Abstract
A method for treating a water slurry of granulated blast furnace slag containing particles of granulated slag having a size consist of about 0.635 centimeter .times. 0 (1/4 inch by 0) wherein a size separation of the particles is made at about 100 sieve. The sink fraction i.e. coarse particles larger than 100 mesh are partially dewatered and thermally dried prior to being comminuted with raw materials to make portland blast furnace slag cement. The float fraction i.e. fine particles smaller than 100 mesh can be used as is or partially dried prior to being used as an additive or extender for a cementitious material in the production of concrete products.
Claims19
A method for preparing a water slurry of granulated blast furnace slag containing about 5 to 15 weight percent solids which have a particle size of 0.635 centimeter.times.0, for use in producing portland blast furnace slag cement and as a cementitious extender in producing concrete products comprising:
- (a) screening the water slurry to separate and remove substantially all foreign matter from the water slurry,
- (b) charging the water slurry into a classifier wherein the particles are separated into a coarse fraction and a fine fraction,
- (c) partially dewatering the coarse fraction in a dewatering device and collecting the fine fraction in a tank,
- (d) discharging the coarse fraction from the dewatering device to storage wherein a second portion of water is allowed to drain naturally from the coarse fraction,
- (e) thermally drying the coarse fraction to remove substantially all the remaining moisture therefrom,
- (f) mixing the coarse fraction with raw materials suitable for producing portland blast furnace slag cement,
- (g) comminuting the mixture of step (f) to specified size, and
- (h) adding the fine fraction as an extender to cementitious materials in the manufacture of concrete products.
A method for using granulated blast furnace slag in the preparation of cement and concrete products, comprising:
- (a) preparing a slurry of granulated blast furnace slag particles having a size consist of about 0.635 centimeter.times.0 in water,
- (b) charging the slurry into a classifier wherein a size separation comparable to that made on a screen size within a range of 65 to 200 mesh sieve size is made;
- the coarse particles comprising a sink fraction and the fine particles comprising a float fraction which contain about 5.0 weight percent of the particles in the granulated blast furnace slag slurry,
- (c) partially dewatering the particles in the sink fraction and collecting the particles in the fine fraction as an overflow from the classifier,
- (d) storing the partially dewatered particles of the sink fraction for a time to allow a second portion of water to drain naturally separate from the particles,
- (e) thermally drying the particles,
- (f) combining the particles with raw materials suitable to make a cement composition,
- (g) comminuting said dried particles, and
- (h) adding the particles in the fine fraction to cementitious materials to produce concrete products.
A method for preparaing granulated blast furnace slag for use in producing portland blast furnace cement and cement products comprising:
- (a) preparing a slurry of granulated blast furnace slag particles having a size consist of 0.635 centimeter.times.0 with water,
- (b) screening the slurry to remove foreign matter therefrom,
- (c) charging the slurry into a classifier wherein a size separation comparable to that made on a sieve within a range of 65 to 200 mesh size is made, the coarse size particles reporting as a sink fraction and the fine size particles reporting as a float fraction,
- (d) partially dewatering the coarse sink fraction,
- (e) thermally drying the coarse sink fraction,
- (f) mixing the coarse sink fraction particles with a material suitable to produce portland blast furnace slag cement,
- (g) grinding the coarse sink fraction particles and material to a size useful for cement, and
- (h) mixing the fine sink fraction particles as an extender with cementitious material to manufacture concrete products.
Dependencies are inferred from the claim text.