Background technology:
There is the huge high-iron gibbsite of reserves in China, and high-iron gibbsite mainly is made up of gibbsite, pyrrhosiderite, rhombohedral iron ore and kaolinite, contains Al in the ore
2O
320~27%, Fe
2O
335~48%, be characterized in salic and two kinds of useful components of ferric oxide of while in the ore, and iron oxide content ratio aluminum oxide content height.
If consider by the standard of bauxite, iron ore, the aluminum oxide and the iron oxide content of this high-iron gibbsite are on the low side, all do not reach the requirement of industrial utilization grade separately, but main valuable mineral gibbsite, pyrrhosiderite and rhombohedral iron ore sum in the ore account for about 70% of mineral total amount.Therefore, this ore deposit has comprehensive development and utilization value preferably.From economically, the grade of aluminum oxide and iron is lower, if aluminum oxide or iron only in the single extraction ore all are uneconomic, must consider aluminum oxide and iron are reclaimed simultaneously on technical scheme, can obtain favorable economic benefit.Aluminium industry does not both at home and abroad at present also utilize the processing method of this high-iron gibbsite.
Red mud reclaims can obtain high-grade sponge iron, sponge iron is metallurgical industry starting material in short supply, can be used to produce high-grade alloy steel, in special steel and seamless steel tube production, all need certain sponge iron proportioning, just can produce quality products, also alternative steel scrap is used for steel-making, and China's sponge iron production at present still is in the starting stage, is badly in need of greatly developing.
Summary of the invention:
The objective of the invention is to: (iron level reaches 35~40%, is equivalent to Fe to the red mud of high-iron gibbsite after bayer process extracts aluminum oxide
2O
351~59%), adopt reducing roasting, magnetic separation process to produce high-grade sponge iron, aluminum oxide and iron in the ore are comprehensively reclaimed.
The present invention is achieved in that the red mud of high-iron gibbsite after bayer's process extracts aluminum oxide, being deposited in the red mud storehouse earlier dries moisture content to 10~20%, send into batch bin, by weight red mud: coal: the mixed of chats=76: 18: 6, transport soil kneader extrusion molding under 300 ℃ of temperature again to, dry, then industrial coal is together added rotary kiln by the amount and the dried agglomerate of 650~750kg/t-sponge iron, under 1100~1200 ℃ of conditions, carry out reducing roasting, material was turning round kiln residence time 4~6 hours, 1000 ℃ of kiln discharge temperature, cool then to below 70 ℃, send the magnetic separation operation again, the residual coal in the grog is removed in a magnetic separation, flyash, agglomerate carries out fragmentation with crusher, be milled down to 200 orders 75~85% with ball mill again, levigate back slip carries out the secondary magnetic separation with magnetic separator, the iron sponge powder that obtains after filtering, by weight the magnetic thing: binding agent: the mixed of unslaked lime=100: 6: 1, mixture carries out extrusion molding with nodulizer, under 100 ℃ of conditions dry 2~3 hours again, obtain ball piece product.
The intensity control of a magnetic separation is at 1000~1500 oersteds, and the secondary magnetic separation strength is controlled at 300~500 oersteds.
Agglomerate after the magnetic separation is L/S=0.8~1.0 in the ore grinding liquid-solid ratio of ball milling operation, and secondary magnetic separation liquid-solid ratio is L/S=9~11.
Mixture pressure during extrusion molding in nodulizer is 40.0Mpa.
Used nodulizer is the high pressure roller nodulizer.
Described binding agent is syrup waste liquid (natural adhesive) or other synthetic macromolecule binding agent.
Described chats is the intermediate product of secondary magnetic separation operation, i.e. iron sponge powder.
In addition, part provinces and regions, China south have a large amount of high ferro diaspore ores, and iron oxide content 14~22% in the ore, adopt bayer's process to extract the tailings red mud that obtains behind the aluminum oxide, its iron oxide content also can adopt the present invention to obtain high-grade sponge iron 30~38% as calculated.
The sponge iron quality product that the present invention obtains (unit: %) as follows:
(1) reducing roasting is after the iron sponge powder that magnetic separation obtains, and its chemical constitution is as follows:
TFe | MFe | CaO | MgO | SiO
2 | Al
2O
3 | Na
2O
| S | P | C |
≥92 | ≥85 | ~0.2 | ~0.1 | ~1.6 | ~1.3 | ~0.04 | ~0.10 | ~0.12 | ~0.32 |
(2) chemical constitution of finished product sponge iron blocks is as follows:
TFe | MFe | CaO | MgO | SiO
2 | Al
2O
3 | Na
2O
| S | P | C |
≥87 | ≥80 | ~1.1 | ~0.1 | ~1.5 | ~1.3 | ~0.03 | ~0.10 | ~0.11 | ~0.30 |
The finished product sponge iron blocks be shaped as the egg sphere, volume is approximately 6.0cm
3, balling ratio 〉=90%.
Adopt method provided by the invention, can reclaim aluminum oxide and iron in the high-iron gibbsite simultaneously, reached the purpose of comprehensive utilization Mineral resources, can obtain favorable economic benefit.
Red mud reclaims can obtain high-grade sponge iron, and sponge iron can be used to produce high-grade alloy steel, all needs certain sponge iron proportioning in special steel and seamless steel tube production, just can produce quality products.The also alternative steel scrap of sponge iron is used for steel-making.
Embodiment:
Embodiments of the invention 1: the red mud water ratio of sending here from alumina producer is 20~30%, be deposited in the red mud storehouse of iron work earlier, moisture content is dried to about 10%, send into batch bin, by weight red mud: coal: after the mixed of chats (intermediate product of secondary magnetic separation operation)=76: 18: 6, transport soil kneader extrusion molding, drying to, the shaping and drying temperature is 300 ℃.Then industrial coal is together added rotary kiln by the amount and the dried agglomerate of 700kg/t-sponge iron, carry out reducing roasting under 1150 ℃ of conditions, material was turning round kiln residence time 5 hours, 1000 ℃ of kiln discharge temperature.Entering cooling water flow in pond then cools to below 70 ℃, grog agglomerate after the cooling send the magnetic separation operation, a magnetic separation strength is 1300 oersteds, remove residual coal, flyash in the grog, agglomerate carries out fragmentation with crusher, be milled down to 200 orders 80% with ball mill again, the ore grinding liquid-solid ratio is L/S=0.8~1.0.Levigate back slip carries out the secondary magnetic separation with magnetic separator, and magnetic separation strength is 400 oersteds, and the magnetic separation liquid-solid ratio is L/S=9~11.The iron sponge powder that magnetic separation obtains after filtering, make binding agent with the syrup waste liquid, by weight the magnetic thing: binding agent: the mixed of unslaked lime=100: 6: 1, mixture carries out extrusion molding with the high pressure roller nodulizer, forming pressure is 40.0Mpa, send drying shed again under 100 ℃ of conditions dry 2 hours, promptly obtain ball piece product.
Embodiments of the invention 2: alumina producer is sent the red mud of iron work, Fe here
2O
3Content usually 〉=30%, moisture content is usually between 20~30%.Also can use red mud dump to deposit the dried red mud in many years, moisture content is in 10~20% scopes.The grog that reducing roasting obtains can adopt one section ball milling in the ball milling operation, also can adopt two sections ball millings.