CN103641158A - Method for preparing Ca2PbO4 powder by using solid phase synthetic method - Google Patents

Abstract

The invention belongs to the technical field of powder preparation, and relates to a method for preparing Ca2PbO4 powder. The method comprises the steps of (1) mixing a calcium salt with a lead salt according to a certain proportion, fully grinding powder unit the components are uniformly mixed; (2) compacting the mixture in a corundum crucible, and then performing a high-temperature reaction in a muffle furnace; (3) grinding, screening, fully washing and purifying by using a cleaning solution, filtering to separate a product, washing the product with deionized water, and filtering and drying to obtain high-purity Ca2PbO4 powder. According to the method, synthetic raw materials are available and are low in price, the process is simple, the operation is convenient, the prepared Ca2PbO4 is uniform in crystal morphology, cube-shaped in appearance and complete in crystal form, and the purity of the Ca2PbO4 can reach more than 99%.

Description

A kind ofly with solid-phase synthesis, prepare Ca 2pbO 4the method of powder

 

Technical field

The invention belongs to powdered material field, relate to a kind of Ca ₂pbO ₄the preparation method of powder.

 

Background technology

According to superconducting material technology, be new and high technology 21st century with strategic importance, bismuth series superconducting material has produced profound influence as at present unique superconducting material of obtaining mass-producing application to the science and technology of contemporary society.Ca ₂pbO ₄to be present in a kind of important component in bismuth series superconducting material, it is formed at bismuth is the superconducting precursor powder heat treatment process initial stage, be considered to indispensable phase composition in bismuth series superconducting material, in the one-tenth phase process of superconducting material, play an important role (Yang little Peng etc. amorphous phase TEM research [J] in the BSCCO band at thermal treatment initial stage. Rare Metals Materials and engineering .2013,37 (4): 142-145).Therefore, prepare highly purified Ca ₂pbO ₄for its concrete effect in bismuth series superconducting material preparation process of research and significant on the impact of bismuth series superconducting material performance.

At present, the chemical process of preparing powder is a lot, comprising: gas phase synthesis method, liquid phase reaction method, solid-phase synthesis etc.Gas phase synthesis method mainly comprises gas-phase decomposition method and gas phase synthesis method, is mainly applicable to prepare metal, nitride, carbide, boride etc.Liquid phase reaction method has the precipitator method, sol-gel method, microemulsion method and hydrothermal method etc.While using the precipitator method, prepared material need obtain by the various chemical reactions in solution, and is precipitated as jelly, and washing, filtration difficulty and precipitation agent are easily sneaked into product and be difficult for removing.Sol-gel method needs with an organic solvent, easily from solvent, introduces carbon impurity, difficult removal, and crystal easy-sintering.Microemulsion method is in two parts of identical microemulsions, to add respectively two kinds of reactants to make it to occur chemical reaction, and then isolates product.Hydrothermal method is under high pressure, reactant and water to be heated, and powder generates by nucleating growth.In above method, what have needs specific equipment, and some technique is more complicated, and raw materials cost is high, and environment protecting is poor, is difficult for promoting.

Solid synthesis method comprises that thermal decomposition method, composite oxides solid reaction process, reducing are legal etc., solid state powder synthesis method preparation technology is simple, without solvent, capacity usage ratio is high, cost is low, productive rate is high, is applicable to scale production.

Summary of the invention

The present invention has realized with the synthetic Ca of solid state powder synthesis method ₂pbO ₄, the Ca after purified ₂pbO ₄crystalline phase is complete, and crystal morphology is single, is regular cubic structure, and purity is higher than 99%.Present method is not introduced any impurity metallic elements in building-up process, and purification process is simple and less demanding to plant and instrument, and in purge process, Pb Elements Leaching is few, environmentally friendly, is applicable to batch production.

Reaction raw materials of the present invention is mixed by calcic and leaded powder, controls the stoichiometric ratio of calcium lead element between 2:1 ~ 3:1.Detailed technology scheme of the present invention is:

A kind ofly with solid-phase synthesis, prepare Ca ₂pbO ₄the method of powder, comprises the following steps:

(1), take calcium salt and lead salt pressed powder, in agate mortar, fully grind, make two kinds of materials to mix completely, wherein, described calcium salt is calcium oxide or nitrocalcite, described lead salt is lead nitrate or plumbous oxide, and calcium and lead element stoichiometric ratio are between 2:1 ~ 3:1;

(2), mixed powder that step 1 is obtained is placed in compacting in corundum crucible, then crucible is placed in to high-temperature roasting in retort furnace, reaction generates Ca ₂pbO ₄, wherein, temperature is controlled at 600 ~ 800 ℃, time 24h;

(3) Ca, step 2 being obtained ₂pbO ₄grind, sieve, with washings ultrasonic cleaning 3 ~ 8 times, each 2 ~ 10min also filters to isolate product, then uses deionized water wash 3 ~ 8 times, and filtration under diminished pressure carries out solid-liquid separation, the dry high-purity C a that obtains ₂pbO ₄powder, wherein, is ground to Ca ₂pbO ₄granularity is 60 ~ 120 microns, and described washings is a kind of in 0.5% ~ 3% ammonium chloride solution, pH=4 ~ 5 hydrochloric acid soln, pH=4 ~ 5 sulphuric acid soln, pH=4 ~ 5 acetum.

The invention has the advantages that: invented Ca ₂pbO ₄solid state powder synthesis method and purification process, present method, in building-up process, does not relate to organic solvent, without other element adding except Ca, two kinds of elements of Pb, therefore can not introduce impurity element yet.Purification step is simple, and washing effect well and is not destroyed product structure, and the washings that uses is easily removed, noresidue.Ca prepared by the method ₂pbO ₄crystal morphology homogeneous and rule, purified rear purity is high.Dried product stable chemical nature, convenient preservation so that follow-up study.

Technique of the present invention is simple, and reagent raw material is easy to get, and has realized low cost, the high-purity C a of high benefit ₂pbO ₄the preparation method of powdered material, has the economic feasibility of industrialized production.Products obtained therefrom of the present invention can be used as standard substance for the correlative study of bismuth series superconducting material, and optimizing, the aspects such as bismuth series superconducting material performance are significant.

Accompanying drawing explanation

Fig. 1 is gained Ca of the present invention ₂pbO ₄x-ray powder diffraction figure and the standard diagram of powder,

Fig. 2 is gained Ca of the present invention ₂pbO ₄the scanning electron microscope (SEM) photograph of powder.

 

Embodiment

Embodiment: the present embodiment is basic embodiment.A kind ofly by pressed powder synthesis method, prepare Ca ₂pbO ₄method, comprise the following steps:

Preparation: take 5.0g plumbous oxide or 7.5g lead nitrate pressed powder, 2.5 ~ 4.0g calcium oxide or 7.7 ~ 11.6g nitrocalcite pressed powder fully grind, make two kinds of materials to mix completely in agate mortar.Mixed powder is placed in to compacting in corundum crucible, crucible is placed in to 600 ~ 800 ℃ of high-temperature roastings in retort furnace, soaking time 24h.

Purifying: products obtained therefrom is ground, sieve, with washing soln supersound washing 3 ~ 8 times, each 2 ~ 10min, then use deionized water wash 5 times, and filter, dry.Adopt filtration under diminished pressure to carry out solid-liquid separation, after oven dry, obtain pure Ca ₂pbO ₄powder.

Table 1 experimental result

thisthe Ca that invention prepares ₂pbO ₄for off-white powder, the result of X-ray powder diffraction (Fig. 1) can obtain, and is Ca in the product preparing ₂pbO ₄phase, scanning electron microscope (SEM) photograph (Fig. 2) shows gained Ca ₂pbO ₄for regular cubes.By chemical method, detect Ca in product ₂pbO ₄percentage composition reach as high as more than 99%, purity is higher.Stable in products obtained therefrom air, kept dry.

The above is only the preferred embodiment for the present invention; it should be pointed out that the member of ordinary skill for the art, do not departing under the prerequisite of the technology of the present invention principle; can also make some improvement and modification, these improve and modification also should be considered as protection scope of the present invention.

Claims (1)

1. with solid-phase synthesis, prepare Ca for one kind ₂pbO ₄the method of powder, is characterized in that, the method comprises the following steps:

(1), take calcium salt and lead salt pressed powder, in agate mortar, fully grind, make two kinds of materials to mix completely, wherein, described calcium salt is calcium oxide or nitrocalcite, described lead salt is lead nitrate or plumbous oxide, and calcium and lead element stoichiometric ratio are between 2:1 ~ 3:1;

(2), mixed powder that step 1 is obtained is placed in compacting in corundum crucible, then crucible is placed in to high-temperature roasting in retort furnace, reaction generates Ca ₂pbO ₄, wherein, temperature is controlled at 600 ~ 800 ℃, time 24h;

(3) Ca, step 2 being obtained ₂pbO ₄grind, sieve, with washings ultrasonic cleaning 3 ~ 8 times, each 2 ~ 10min also filters to isolate product, then uses deionized water wash 3 ~ 8 times, and filtration under diminished pressure carries out solid-liquid separation, the dry high-purity C a that obtains ₂pbO ₄powder, wherein, is ground to Ca ₂pbO ₄granularity is 60 ~ 120 microns, and described washings is a kind of in 0.5% ~ 3% ammonium chloride solution, pH=4 ~ 5 hydrochloric acid soln, pH=4 ~ 5 sulphuric acid soln, pH=4 ~ 5 acetum.

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