CN102910923A

CN102910923A - Method for synthesizing corundum-mullite composite phase material by using bauxite tailings

Info

Publication number: CN102910923A
Application number: CN2012104611039A
Authority: CN
Inventors: 张梅; 郭敏; 马冬阳; 王振东; 苑德志; 彭犇; 岳昌盛
Original assignee: University of Science and Technology Beijing USTB
Current assignee: University of Science and Technology Beijing USTB
Priority date: 2012-11-15
Filing date: 2012-11-15
Publication date: 2013-02-06
Anticipated expiration: 2032-11-15
Also published as: CN102910923B

Abstract

A method for synthesizing a corundum-mullite composite phase material by using bauxite tailings, and belongs to the field of refractory materials. A raw material for synthesizing corundum-mullite is the bauxite tailings. The method comprises the steps of grinding by a ball mill and homogenizing the isabelline granulated bauxite tailings with original particle size being about 100 mu m as the raw material to obtain the mineral powder with the average particle size being smaller than 10mu m; activating and roasting the grinded mineral powder for 2-4hours at the temperature of 630-820DEG C; performing acid leaching on the roasted mineral powder with the liquid-solid ration of about 1:10 in 2.5mol/L-4.3mol/L hydrochloric acid for 1-3hours at the temperature higher than 90 DEG C; performing temperature preservation on the finished concentrate subjected to the acid leaching for 3-6 hours at the temperature of 1450-1650 DEG C; and synthesizing under air atmosphere. According to the invention, the raw material is rich, the price is low, the synthesized corundum-mullite composite phase material is very pure, various performances of the material are remarkably improved, high added value is realized, and the method is a new path for preparing high temperature refractory materials.

Description

A kind of method with bauxite gangue synthetic corundum-mullite complex phase material

Technical field

The invention belongs to fire resisting material field, particularly a kind of corundum-mullite composites.

Background technology

Because mullite has good high-temperature mechanics, high temperature thermal property, makes the mullite synthesizing goods have higher density and purity, lower heat-conduction coefficient and thermal expansivity, thermal structure intensity is high, high temperature creep rate is low, and heat-shock resistance and chemical corrosion are strong, the fusing point advantages of higher; And the corundum good springiness, fusing point is high, at high temperature has good wear-resisting, chemical resistance of concrete and volume stability, and hardness is large, and refractoriness is high; Mullite crystal is generally column or prism-shaped in addition, the corundum body is generally granular, so the preparation corundum-mullite composites will compile the two-fold advantage of corundum crystal and mullite crystal, thereby make this material all be better than in every respect single-phase mullite material or corundum material.At present the general alumine that adopts is with sintering process or electric smelting legal person worker mullite synthesizing, if but synthesize with pure raw material then seriously improved the production cost of material, especially as refractory materials.Therefore, adopt the production cost that natural matter undoubtedly can the decrease material.

China's bauxite characteristics are low alumina-silica ratios, can only adopt ore dressing-alumina producing Bayer process, the main solid waste that produces after the ore dressing is bauxite gangue, bauxite raw ore per ton will produce the bauxite gangue of about 20% ~ 30% quality, mine tailing is not large-scale developed and utilized at present, generally just stacks in tailing dam.The accumulation of mine tailing can cause the problems such as alkalization of soils, environmental pollution.Aluminium industry is at development, and the mine tailing amount will be increasing, and therefore, the development and utilization of bauxite gangue has become the task of top priority.The main chemical compositions of bauxite gangue is Al ₂O ₃And SiO ₂, generally about 70%, other has a small amount of Fe to the two content sum ₂O ₃, TiO ₂, K ₂O etc.Al ₂O ₃With SiO ₂Be the main component of industrial production aluminosilicate series refractory material, can consider with bauxite gangue as the raw material of producing the aluminosilicate series refractory material.

Summary of the invention:

The object of the invention is the existing resource in conjunction with China, take full advantage of and promote solid waste resource recovery recycling, selected the solid waste bauxite gangue to come synthetic fire resistive material, make corundum-mullite composites, not only take full advantage of existing resource, simultaneously also reduced the pollution that solid waste is brought, greatly reduced production costs.

A kind of method with bauxite gangue synthetic corundum-mullite complex phase material, mainly take bauxite gangue as raw material, Al in the bauxite gangue ₂O ₃The content weight percent is about 45% ~ 65%, SiO ₂Content is about 20% ~ 25%, contains simultaneously 10 ~ 15% Fe ₂O ₃And 2% ~ 4% K ₂O, all the other materials are mainly crystal water.

Its synthetic method is:

(1) the bauxite gangue raw material is isabelline particulate state, initial size is of a size of about 100 μ m, for reducing the particle diameter of mineral powder granular, increase its specific surface area, increase its chemical reactivity, and its chemical ingredients is evenly distributed, with breeze levigate and homogenizing in ball mill, the median size of the breeze that obtains is less than 10 μ m.

(2) to 4 hours, met and progressively decompose, and obtains Al after the decomposition by the diaspore in the calcination for activation process in the bauxite gangue, kaolinite, Erie's stone ore at 630 ℃ ~ 820 ℃ calcination for activation 2 for the bauxite gangue after levigate ₂O ₃, SiO ₂, K ₂O and Fe ₂O ₃Deng, the chemically reactive of these compositions improves a lot before comparing roasting, hydrochloric acid removal of impurities flow process and sintering synthesis flow after being conducive to.

(3) breeze after the bauxite gangue roasting behind the calcination for activation with liquid-solid ratio 1:10 about in the hydrochloric acid of concentration 2.5mol/L to 4.3mol/L in acidleach 1.5 more than 90 ℃ to 3.5 hours, most Fe ₂O ₃With K ₂O can be dissolved among the hydrochloric acid, most Al ₂O ₃With SiO ₂Can be retained among the solid phase, through the solid-liquid separation process, obtain pure concentrate substantially free from foreign meter.

(4) carried out sintering in 3～6 hours 1450 ℃～1650 ℃ insulations after the concentrate moulding that obtains after the acidleach and synthesize, synthetic atmosphere is air, the Al in the concentrate ₂O ₃With SiO ₂Composition reacts and generates the mullite-corundum complex phase.

Through test, and the composition of composite diphase material that utilized XRD analysis, test-results shows: synthetic is corundum-mullite composites, can find out that from the analysis of SEM fracture apperance crystal morphology is typical long column shape crystal and bulk crystals growth interlaced with each other, compact structure.

The foreign matter content of bauxite gangue is higher, particularly Fe ₂O ₃With K ₂O impurity, it will have a strong impact on the building-up process of mullite complex phase material, can't come the mullite synthesizing composite diphase material with bauxite gangue with ordinary process.This seminar is through for many years research, discovery is carried out first 2 to 4 hours calcination for activation at 630 ℃ ~ 820 ℃ to bauxite gangue, the concentrate that obtains again with about liquid-solid ratio 1:10 in the hydrochloric acid of concentration 2.5mol/L to 4.3mol/L in acidleach 1 more than 90 ℃ to 3 hours, can significantly reduce the Fe in the mine tailing ₂O ₃With K ₂O impurity, the Al after the acidleach in the mine tailing ₂O ₃With SiO ₂Chemically reactive also significantly improve, it can obtain corundum-mullite composites in 3～6 hours at 1450 ℃～1650 ℃ sintering.

The invention has the advantages that: because the main raw material of synthetic corundum-mullite is bauxite gangue, it is a kind of discarded resource, synthetic corundum-mullite composites has very high added value, so be another new way of preparation high-performance refractory material, and meet the industry policy of " recycling economy " that country advocates.

Description of drawings:

Fig. 1: with the process flow sheet of bauxite gangue synthetic corundum-mullite complex phase material

Fig. 2: with the XRD figure spectrum of the synthetic corundum-mullite complex phase of bauxite gangue

Fig. 3: the corundum-mullite composites SEM synthetic take bauxite gangue as raw material schemes

Embodiment:

1. raw material is chosen

Raw material is bauxite gangue in the Henan, and the chemical analysis results of bauxite gangue is as shown in table 1:

Table 1: the chemical ingredients of bauxite gangue

?	Al ₂O ₃	SiO ₂	Fe ₂O ₃	TiO ₂	K ₂O	Crystal water
							Bauxite gangue	49.87	22.45	13.1	2.61	2.25	9.72

2. synthesis step: see Fig. 1

From XRD figure, see very clearly in the mark and under this test conditions, synthesized very pure corundum-mullite composites.

Can find out that from the analysis of SEM fracture apperance crystal morphology is typical column crystal, the intensive growth of mutually staggered.

Claims

1. method with bauxite gangue synthetic corundum-mullite complex phase material is characterized in that:

Take bauxite gangue as raw material, Al in the bauxite gangue ₂O ₃The content weight percent is 45% ~ 65%, SiO ₂Content is 20% ~ 25%, contains simultaneously 10 ~ 15% Fe ₂O ₃, 2% ~ 4% K ₂O, 2% ~ 4% TiO ₂, all the other are crystal water;

The step of synthetic corundum-mullite is:

(1) the bauxite gangue raw material is isabelline particulate state, initial size is of a size of 100 μ m, for reducing the particle diameter of mineral powder granular, increase its specific surface area, increase its chemical reactivity, and its chemical ingredients is evenly distributed, with breeze levigate and homogenizing in ball mill, the median size of the breeze that obtains is less than 10 μ m;

To 4 hours, met and progressively decompose, and obtains Al after the decomposition by the diaspore in the calcination for activation process in the bauxite gangue, kaolinite, Erie's stone ore at 630 ℃ ~ 820 ℃ calcination for activation 2 for bauxite gangue after levigate ₂O ₃, SiO ₂, K ₂O and Fe ₂O ₃, the chemically reactive of these compositions improves a lot before comparing roasting, hydrochloric acid removal of impurities flow process and sintering synthesis flow after being conducive to;

(3) breeze after the bauxite gangue roasting behind the calcination for activation with the ratio of liquid-solid ratio 1:10 in the hydrochloric acid of concentration 2.5mol/L to 4.3mol/L in acidleach 1.5 more than 90 ℃ to 3.5 hours, most Fe ₂O ₃With K ₂O can be dissolved among the hydrochloric acid, most Al ₂O ₃With SiO ₂Can be retained among the solid phase, through the solid-liquid separation process, obtain pure concentrate free from foreign meter;

Carried out sintering in 3～6 hours 1450 ℃～1650 ℃ insulations after the concentrate moulding that obtains after the acidleach and synthesize, synthetic atmosphere is air, the Al in the concentrate ₂O ₃With SiO ₂Composition reacts and generates the mullite-corundum complex phase.