CN105014090A - Method for preparing TiFe alloy by reducing ferrotitanium oxide under microwave field - Google Patents

Abstract

The invention relates to a method for preparing a TiFe alloy by reducing a ferrotitanium oxide under a microwave field; and the method uses microwave heating for quickly heating titanium and iron oxides and an added reducing agent, and uses a reduction action to synthesize the TiFe alloy. The method has the following characteristics: CaH2 is adopted as the reducing agent, and is uniformly mixed with a titanium and iron oxide mixture (TiO2+Fe2O3) or a ferrotitanium ore (FeTiO3) through ball milling; and because of the characteristic of easy generation of interaction between the titanium and iron oxides and the microwave field, raw materials are uniformly heated to a temperature of 1273-1473 DEG C, and the temperature is kept by 40-80 min, so that the raw materials generate the reduction reaction under high temperature. Then, samples are cleaned by acetic acid water solution to obtain TiFe powder with a purity of 70-85%. The method is simple and feasible, overcomes the problems of high energy consumption and high raw material cost in the conventional suspension smelting precision of ferrotitanium alloys, and fully uses the advantages of speediness and high efficiency in microwave heating.

Description

The Fe-Ti oxides that reduces under microwave field prepares the method for TiFe alloy

Technical field

The Fe-Ti oxides that reduces under the present invention relates to a kind of method of TiFe alloy, particularly a kind of microwave field prepares the method for TiFe alloy.

Background technology

Along with being on the rise of environmental pollution and petering out of fossil energy, new forms of energy especially Hydrogen Energy cause the great interest of people as a kind of clean, free of contamination green energy resource, carried out R and D widely to it.The applicable key issue of restriction hydrogen is safe and reliable hydrogen storage technology.Hydrogen storage technology is mainly divided into gaseous state to store up hydrogen, liquid storage hydrogen and solid-state storage hydrogen.Solid-state storage hydrogen because of its security and hydrogen-storage density high and study the most extensive.In solid-state hydrogen storage material, TiFe series hydrogen storage alloy is subject to extensive concern because having the advantages such as hydrogen storage amount is large, low price, suction hydrogen discharging temperature are low, but also has that smelting temperature is high, energy consumption is large and the problem such as activation condition is harsh.In order to solve the problem, current researcher, mainly through approach such as element substitution or interpolation, surface modification, mechanical ball milling and plastic deformations, makes its activity function be improved.But the problems such as its smelting is difficult, energy consumption is large not yet solve.Nearest Tsuchiya etc. devise one and utilize calcium metal as reducing agent, TiO ₂with Fe as raw material, self-propagating combustion is adopted to prepare the method (International Journal of Hydrogen Energy, 38,6681-6686,2013) of ferrotianium hydrogen bearing alloy.The method adopts TiO ₂replace Ti, reduce raw-material cost; Utilize self-propagating combustion to decrease the energy consumption of TiFe reasonable offer, the smelting for TiFe alloy provides new approach.But the method utilizes conventional resistive stove as heating container, in stove, sample relies on the radiant heat transfer of furnace wall to heat up, and most energy ezpenditure is in the heating and insulation of body of heater self, and the heat conductivility of metal oxide powder is poor, and capacity usage ratio is lower; In addition, the reducing agent calcium metal of employing is softer due to physical property own, and can not be made into powder and use, so need the calcium of the chemical reaction equivalent of twice that reaction just can be impelled to carry out more abundant, cost of material is higher.

Heating using microwave is a kind of brand-new heat energy technology of being carried out conducting self-heating by the energy of material absorbing microwave.Compared with conventional heating techniques, heating using microwave has the features such as the efficiency of heating surface is high, firing rate is fast, selective heating, globality heating.1967, Ford and Pei just carried out irradiation with microwave to charcoal and 17 kinds of oxides and sulfide, wherein finds Fe ₂o ₃1273K (The Journal of Microwave Powder, 2 (2), 61-64,1967) just can be heated within a few minutes; Walkiewiez etc. find to utilize heating using microwave to may be used for the carbon thermal reduction (Minerals and Metallurgical Processing, 28 (2), 39-42,1988) of ilmenite, and wherein ilmenite can be heated to 1653K in 3.5min.

Summary of the invention

The Fe-Ti oxides that reduces under the object of the present invention is to provide a kind of microwave field prepares the method for TiFe alloy.

The chemical equation that the method adopts is:

2TiO ₂+Fe ₂O ₃+7CaH ₂=7CaO+2FeTi+7H ₂

FeTiO ₃+3CaH ₂=3CaO+FeTi+3H ₂。

To achieve these goals, the present invention adopts following technical scheme:

Reduce the method for Preparation TiFe alloy of titanium and iron under microwave field, it is characterized in that the concrete steps of the method are:

A. by CaH ₂the oxide mixture of powder, titanium and iron or the mixing of ilmenite powder, wherein titanium ion, iron ion and CaH ₂mol ratio be: 1.0:1.0:3.0 ~ 1.0:1.0:7.0; Then under inert gas shielding, carry out ball milling, wherein ball material weight ratio is 10:1, is milled to and fully mixes;

B. by the uniform sample of step a gained ball milling under inert atmosphere protection, under 1000W microwave power, make sample be warming up to 1273 ~ 1473K, and be incubated 40min ~ 80min;

C. TiFe powder is obtained after being cleaned by step b gained sample acetic acid aqueous solution.

The microwave frequency adopted in above-mentioned steps b is 2.45GHz, and the field pattern of microwave is multimode field pattern.

Feature and the mechanism of the inventive method are as described below:

Heating using microwave is different from traditional heating, and traditional heating mode is that external heat source is from outward appearance to inner essence heated by conductive-convective and radiation, to the non-conductor of heat, there is the problems such as the uneven and efficiency of heating surface of heating is low.And heating using microwave is interacted by microwave and dielectric material and produces, have that homogeneous heating, heating rate are fast, efficiency of heating surface advantages of higher.In addition microwave is by the interaction with atom and molecule, for chemical reaction creates favorable conditions, has catalytic action to chemical reaction.The present invention utilizes the oxide of titanium and iron to be easy to the interactional characteristic with microwave field, adopts CaH ₂as reducing agent, achieve the oxide mixture (TiO of direct-reduction titanium and iron under microwave field ₂+ Fe ₂o ₃) or ilmenite (FeTiO ₃) prepare TiFe hydrogen bearing alloy, the method had both overcome the problem that ferro-titanium high energy consumption and high cost of material are prepared in conventional suspension melting, took full advantage of again heating using microwave advantage rapidly and efficiently.

Based on the absorbing property of the advantage of heating using microwave and the oxide of titanium and iron, the present invention proposes one and utilizes CaH ₂make reducing agent, by the method for the Preparation TiFe alloy of heating using microwave direct-reduction titanium and iron.The process employs 2 kinds of Fe-Ti oxides raw materials, a kind of is the mixture (TiO of titanium oxide and iron oxide ₂+ Fe ₂o ₃), another kind is ilmenite titanium (FeTiO ₃).These 2 kinds of raw materials can be TiFe alloy by direct-reduction, decrease the preparation section of metal simple-substance Ti and Fe needed for traditional smelting method, significantly reduce raw-material energy consumption and cost; Adopt heating using microwave can realize the overall efficient Fast Heating of raw material, reduce the energy consumption of conventional resistive stove radiant heat transfer process; The ferrotianium powder size obtained after being filtered by pickling can reach micron level, improve the activity function of alloy, decrease alloy that conventional method melting obtains activate required for energy and the time, for TiFe alloy provides new preparation technology and performance improvement approach.

The method is simple, has both overcome the problem that ferro-titanium high energy consumption and high cost of material are prepared in conventional suspension melting, takes full advantage of again heating using microwave advantage fast and efficiently.

Advantage of the present invention is as described below:

(1) CaH is adopted ₂powder is as the oxide (TiO of reducing agent direct-reduction titanium and iron ₂+ Fe ₂o ₃feTiO ₃), decrease the preparation section of metal simple-substance Ti and Fe needed for traditional smelting method, significantly reduce raw-material energy consumption and cost.

(2) adopt heating using microwave to realize raw-material uniform high-efficiency Fast Heating, reduce the energy consumption of conventional resistive stove radiant heat transfer process, avoid the problem of metal oxide powder heat conductivility difference, promote the carrying out of reduction reaction.

(3) CaH is adopted ₂powder is reducing agent, can mix with the oxide ball milling of titanium and iron, fully contacts, be beneficial to reaction and carry out completely when ensureing to react between each reactant.

(4) the ferrotianium powder size obtained after being filtered by pickling can reach micron level, improves the activity function of alloy.

Accompanying drawing explanation

Fig. 1 is the temperature-time curve of sample under microwave field in the embodiment of the present invention 1, and other sample heating curve is similar, repeats no more.Heat up under as shown being 1000W initial microwave power rapidly to 1423K, adjustment microwave power, within the scope of 100 ~ 600W, is incubated 65min.

Fig. 2 is the XRD collection of illustrative plates that in the embodiment of the present invention 1, sample obtains product after pickling.

Detailed description of the invention

After now specific embodiments of the invention being described in.Describe in detail for embodiment 1, other embodiment situations refer to table 1, repeat no more.Following examples do not form limitation of the invention.

embodiment 1

By titanium ion, iron ion and CaH ₂mol ratio be: the proportioning of 1.0:1.0:5.2 takes TiO ₂(purity 99.8%), Fe ₂o ₃(purity 99%) and CaH ₂(purity 98.5%) powder, is jointly placed in ball mill and fully mixes by above-mentioned raw materials.Ball material weight ratio in ball mill is 10:1, and the powder that namely every 1 g is heavy needs the abrading-ball that 10 g are heavy, and the speed of mainshaft of ball mill is 300 revs/min, and countershaft rotating speed is-450 revs/min ("-" representative turns to contrary), and Ball-milling Time is 4h, and mill 30min stops 30min; For preventing Powder Oxidation, carry out in the canned sample of sample weighing, ball milling and the glove box of sampling all under Ar atmosphere protection.Uniform for above-mentioned ball milling sample is placed in microwave tube type oven, vacuumize and pass into high-purity argon gas (>=99.999%) protection, opening microwave power supply, make sample be warming up to 1423K in 5 minutes with 1000W microwave, then reduce microwave power to regulate continuously between 200 ~ 600W, insulation 60min; Close microwave, sample cools with stove.Cleaned by the acetic acid aqueous solution of the sample 10wt.% after above-mentioned microwave heating thermal-insulation, filter and obtain the powder that particle size is 10 microns, its XRD diffracting spectrum as shown in Figure 2.As can be seen from Figure 2, the sample before Microwave synthesize is TiO ₂, Fe ₂o ₃and CaH ₂the mixture of phase, the product after Microwave synthesize+pickling is mainly TiFe phase and a small amount of Fe ₂ti phase.This product does not need high-temperature activation to inhale hydrogen, 25 DEG C, hydrogen-sucking amount is 1.3wt.% under 2MPa hydrogen pressure, therefore obtained TiFe alloy purity is 72%.

Claims (2)

1. reduce the method for Preparation TiFe alloy of titanium and iron under microwave field, it is characterized in that the concrete steps of the method are:

A. by CaH ₂the oxide mixture of powder, titanium and iron or the mixing of ilmenite powder, wherein titanium ion, iron ion and CaH ₂mol ratio be: 1.0:1.0:3.0 ~ 1.0:1.0:7.0; Then under inert gas shielding, carry out ball milling, wherein ball material weight ratio is 10:1, is milled to and fully mixes;

B. by the uniform sample of step a gained ball milling under inert atmosphere protection, under 1000W microwave power, make sample be warming up to 1273 ~ 1473K, and be incubated 40min ~ 80min;

C. TiFe powder is obtained after being cleaned by step b gained sample acetic acid aqueous solution.

2. under microwave field according to claim 1, direct-reduction Tai ferriferous oxide prepares the method for TiFe alloy, and it is characterized in that, the microwave frequency adopted in step b is 2.45GHz, and the field pattern of microwave is multimode field pattern.