Process for reducing oxygen content of oxidic mineral ore

Claim 2

A process according to claim 2 in which the second body of particles is disposed on top of a horizontal gas pervious bed of heat transfer media and transported along a horizontal path, the gases are passed downwardly through the body of particles and bed of media in the first zone, and such gases after having passed through the body of particles and bed of media in the first zone and such gases after having passed through the body of particles and bed of media in the first zone are then passed upwardly through the media and the body of oxygen reduced particles in the second zone to raise the temperature of such gases by recovering heat that had been temporarily stored in the media and from the reduced particles, and thereafter such heated gases from the second zone are utilized to form the combined gas stream of such gases recycled with the fresh supply of the rich gases.

Claim 3

A process according to claim 3 in which the heat transfer media in the bed is of a predetermined size larger than the particles in the body of particles disposed thereon, the particles and media are screened after passing through the second zone to separate the relatively larger media from the relatively smaller reduced particles, and the media is thereafter recirculated to again provide a gas pervious bed for particles gathered thereon into a second body for transport through the reducing and heat recover zones.

Claim 4

A process according to claim 4 in which the particles are prepared from fines which are agglomerated into particles of substantially uniform size.

Claim 5

A process according to claim 4 in which the particles are prepared from fines which are rolled in balls of substantially uniform diameter.

Claim 6

A process according to claim 1 in which the mineral ore is particles of oxidic iron ore, the particles in the first body are dried and preheated in an oxidizing atmosphere until any magnetite present is oxidized to hematite and adjacent grains of hematite begin to form mineral bridgEs therebetween, the thereafter tumbling particles are so treated until the reduction of iron ore to wustite (FeO) is at least initiated by the first branch of the gas streams which is changed to oxidizing and utilized to preheat and dry the particles in the first body.

Claim 7

A process of heat-treating mineral ore comprising successively drying, preheating, and reducing the state of oxidation of particles of the ores, and then developing a network of metal bridges through the ore particles, characterized by the steps of: a. gathering the ore particles into a first gas permeable body with the particles at rest relative to each other within the body; b. drying and preheating the body of particles until the particles harden sufficiently to withstand tumbling; c. disrupting the body of particles and imparting tumbling movement to the particles while further heating the particles with heated reducing gases to initiate at least preliminary reduction of the particles to a lower state of oxidation; d. regathering the particles into a second gas permeable body with the particles at rest relative to each other within the body; e. reforming a fuel containing components from a group containing hydrogen and carbonacious components into a stream of reducing gases rich in gases from a group comprising hydrogen and carbon monoxide; f. passing the rich gases through the second body of particles to further reduce the particles; g. dividing the gases that have passed through the second body of particles to reduce the oxygen content thereof into two branch streams with a first of the branch streams being delivered directly to and directed through the particles being tumbled to effect a preliminary reduction thereof prior to regathering the particles into said second body for a final reduction thereof; and h. recyling the other branch stream of gases that have passed through the second body of particles by first mixing therewith a fresh supply of the said stream of gases rich in hydrogen and/or carbon monoxide by reforming a fuel to form a combined gas stream and thereafter passing the combined gas stream through the second body of particles to reduce the state of oxidation of the particles.

Claim 8

A process according to claim 8 in which the gases that have passed through the second body of particles to reduce the oxygen content thereof are thereafter reheated by heat from the fuel reforming step before rich gases of reformed fuel from the reforming step are admixed therewith for forming the combined gas stream for subsequent passing through the second body of particles.