CN101045633A

CN101045633A - Method for preparing Ca-alpha-SiAlON material using iron selection tailings

Info

Publication number: CN101045633A
Application number: CN 200710098825
Authority: CN
Inventors: 徐利华; 毕松梅; 张菡; 毕玉保
Original assignee: University of Science and Technology Beijing USTB
Current assignee: University of Science and Technology Beijing USTB
Priority date: 2007-04-27
Filing date: 2007-04-27
Publication date: 2007-10-03
Anticipated expiration: 2027-04-27
Also published as: CN100418924C

Abstract

A process for preparing Ca-alpha-SiAlON material from the ore tailings generated by iron dressing includes such steps as acid washing, proportionally mixing raw materials, ball grinding, drying, shaping, sintering and removing residual carbon to obtain the ceramic powder whose primary crystal phase is Ca-alpha-SiAlON and whose secondary crystal phase is SiC.

Description

A kind of method for preparing Ca-α-SiAlON material with iron selection tailings

Technical field

The invention belongs to technical field of ceramic material, proposed a kind ofly to prepare the method for Ca-α-SiAlON material, have stronger feasibility with Baogang's iron selection tailings.

Background technology

Owing to reasons such as the fund of China, technology, management cause the unreasonable development and utilization of resource, make the energy and efficiency of resource low.The utilization ratio of the present symbiosis of China, associated minerals has only about 20%, and the mineral products total yield has only 30%, and external advanced level is all more than 50%.Therefore China must greatly develop recycling economy, according to " minimizing, utilize again, resource utilization " principle, takes various effective measure, with the least possible resource consumption and circlet border cost as far as possible, obtains the economic output of maximum and minimum waste discharge.

Ca-α-SiAlON compares Si ₃N ₄The material easy-sintering, it has kept Si ₃N ₄Advantageous property, as intensity, hardness, thermotolerance etc., and toughness, chemical stability and oxidation-resistance all are better than Si ₃N ₄Ca-α-SiAlON material is considered to one of most promising high-temperature structural ceramics with its superior mechanical property, thermal property and chemical stability.Ca-α-SiAlON material is now at blast furnace lining, casting house, hot metal mixer (car) liner, and be widely used on the equipment such as hot metal ladle, steel teeming ladle and slide gate nozzle and heat exchanger member.

Styloid Ca-α-SiAlON preparation methods mainly contains growth in situ method and two-step approach.The growth in situ method is by nucleation process is controlled, and the relatively large nucleus of minority is formed and growth, limits new nucleus simultaneously and forms, and for the nucleus that has formed provides enough growing spaces, the result just can obtain long column shape α-SiAlON crystal grain.Utilize two-step approach preparation from toughness reinforcing α-SiAlON pottery, need earlier synthetic long column shape α-SiAlON powder, and then this powder added to carry out sintering in the batching, finally obtain column Ca-α-SiAlON material preferably.These two kinds of methods all are directly to use ready-made Si, Al, SiO ₂, CaO, AlN and Si ₃N ₄Prepare as raw material, therefore to the mineral composition complexity, it is improper to sample lower raw material.The technology that the present invention is designed has stronger feasibility to the utilization of mine tailing and other low grade materials.

The principle of the invention is mainly finished according to SiAlON pottery liquid phase sintering mechanism.The amount of liquid phase that in sintering process, forms more after a little while, therefore the speed of dissolving-diffusion is slower, is easy to cause around α-SiAlON crystal grain the degree of supersaturation of liquid phase inhomogeneous, existing rounded grain has elongated particle again.And when amount of liquid phase strengthens, dissolving one diffusion is easier to relatively, and the ability of α-SiAlON crystal grain adjustment self pattern will be strengthened, and the liquid phase saturation ratio reduced around the increase of liquid phase simultaneously also may make crystal grain, so crystal grain grows up to germination easily, it is big that grain-size also becomes.Therefore, when the amount of liquid phase that forms in sintering process is many more, the existence of a large amount of liquid phases reduces α-SiAlON suffered growth resistant in growth course, and the structural development according to desirable crystal grain becomes long grain easily.

Though the at present domestic existing patent application of method that in technical field, prepares Ca-α-SiAlON material, but to select the iron rare-earth tailing is that the method that object prepares Ca-α-SiAlON material does not also have patent, therefore, the present invention is a new technology in the preparation of Ca-α-SiAlON stupalith.

Summary of the invention

The object of the present invention is to provide a kind of method that from iron selection tailings, prepares Ca-α-SiAlON material, the one, realized the comprehensive utilization of mine tailing; The 2nd, designed a kind of preparation Ca-α-SiAlON material inexpensive process, reduced cost.

(1) pickling: the concentrated hydrochloric acid that iron selection tailings is adopted 10～12mol/L pickling 6～8 hours under 65～80 ℃ temperature, purpose is to remove most iron and a spot of calcium.The mine tailing composition is: CaO:30-35%, and Fe2O3:32-36%, SiO2:20-25%, Al2O3:4-10%, CeO2:1-3%, MgO:1-1.5%, TiO2:1-2%, other: surplus.

(2) batching: the mine tailing after the pickling is made raw material, with α-Al ₂O ₃Powder, calcium oxide are adjusted composition, as reductive agent, are mixed with compound with carbon black.

(3) ball milling mixes: prepared mixture is put into the urethane ball grinder, and as medium, wet mixing ball milling 20～30 hours is to reach the purpose that mixes with the refinement powder with dehydrated alcohol.

(4) dry sample preparation: the slip behind the above-mentioned ball milling is put into baking oven under 45～60 ℃ temperature, dry, and then the batching that drying is good carried out dry mixed 25～40 minutes, even with the material that realizes batch mixing; With hydropress batch mixing is pressed into cylindric sample again.

(5) sintering: the sample that suppresses is put into tube type resistance furnace, and at 1450～1500 ℃ temperature lower calcination, the feeding nitrogen flow is 0.6～0.8L/min, is incubated 5～7 hours, to realize the abundant sintering of sample.

(6) remove residue carbon elements: the sample behind the sintering is incubated 4.5～5.5 hours under 600～700 ℃ condition,, obtains the Ca-α-SiAlON material of carbon free from foreign meter to remove uncombined carbon component remaining in the sample.

The invention has the advantages that: obtain the having higher degree Ca-α-SiAlON ceramic powder of (mass percent is 65-90%).Can be widely used in industrial circles such as metallurgy, chemical industry, electric power, the energy.By the Technology of lower cost, prepared the Ca-α-SiAlON ceramic powder of excellent property, make mine tailing obtain rationally utilizing fully.

Description of drawings

Fig. 1 is the XRD figure spectrum of gained powder in the embodiment of the invention 1.

Fig. 2 is the XRD figure spectrum of gained powder in the embodiment of the invention 2.

Embodiment

Below introduce the specific embodiment of the present invention by description to embodiment

Embodiment 1:

Use the concentrated hydrochloric acid of 12mol/L 80 ℃ of pickling 7 hours, with pickling slag, α-Al Baogang's mine tailing ₂O ₃Ball milling was 25 hours after powder, calcium oxide and carbon black were prepared burden, compound behind the ball milling was dried 30 minutes down at 50 ℃, press sample, the sample that suppresses was 1450 ℃ of calcinings 6 hours, and the control nitrogen flow is 0.6L/min, and then the calcining after sample under 600 ℃ condition, be incubated 5 hours, principal crystalline phase is Ca-a-SiAlON in the end article that obtains, and contains 35%SiC and trace impurity phase.

Embodiment 2:

Use the concentrated hydrochloric acid of 12mol/L 80 ℃ of pickling 7 hours, with pickling slag, α-Al Baogang's mine tailing ₂O ₃Ball milling was 30 hours after powder, calcium oxide and carbon black were prepared burden, compound behind the ball milling was dried 30 minutes down at 50 ℃, press sample, the sample that suppresses was 1500 ℃ of calcinings 6 hours, and the control nitrogen flow is 0.8L/min, and then the calcining after sample under 600 ℃ condition, be incubated 6 hours, principal crystalline phase is Ca-α-SiAlON in the end article that obtains, and contains 12%SiC and trace impurity phase.

Claims

1, a kind of method of utilizing iron selection tailings to prepare Ca-α-SiAlON material, it is characterized in that: processing step is:

A, pickling: the concentrated hydrochloric acid that iron selection tailings is adopted 10～12mol/L pickling 6～8 hours under 65～80 ℃ temperature, purpose is to remove most iron and a spot of calcium;

B, batching: the mine tailing after the pickling is made raw material, with α-Al ₂O ₃Powder, calcium oxide are adjusted composition, as reductive agent, are mixed with compound with carbon black;

C, ball milling mix: prepared mixture is put into the urethane ball grinder, and as medium, wet mixing ball milling 20～30 hours reaches and mixes and the refinement powder with dehydrated alcohol;

D, dry sample preparation: the slip behind the above-mentioned ball milling is put into baking oven under 45～60 ℃ temperature, dry, and then the batching that drying is good carried out dry mixed 25～40 minutes, even with the material that realizes batch mixing; With hydropress batch mixing is pressed into cylindric sample again;

E, sintering: the sample that suppresses is put into tube type resistance furnace, and at 1450～1500 ℃ temperature lower calcination, the feeding nitrogen flow is 0.6～0.8L/min, is incubated 5～7 hours;

F, removal residue carbon elements: the sample behind the sintering is incubated 4.5～5.5 hours under 600～700 ℃ condition, removes uncombined carbon component remaining in the sample, obtain the Ca-α-SiAlON material of carbon free from foreign meter.

According to the described method of claim l, it is characterized in that 2, the mine tailing composition is: CaO:30-35%, Fe2O3:32-36%, SiO2:20-25%, Al2O3:4-10%, CeO2:1-3%, MgO:1-1.5%, TiO2:1-2%, other: surplus.