Method for preparing lanthanum cuprate (La2CuO4) powder by means of microwave-hydrothermal method

A technology of microwave hydrothermal method and lanthanum cuprate, applied in chemical instruments and methods, copper compounds, inorganic chemistry, etc., can solve problems such as easy sintering of products, poor safety performance, and time-consuming, so as to overcome uneven heating and improve Work efficiency and the effect of shortening the reaction time

Active Publication Date: 2013-10-09
山东格新精工有限公司
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  • Abstract
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Problems solved by technology

[0005] However, these methods have their own shortcomings. For example, in order to obtain a high-purity target product in the solid-state reaction method, the reactant powder should be fine enough, and it needs to be roasted at high temperature for a long time and several times. , and there are more impurity phases in the product; for the self-propagating combustion method, the combustion reaction is very violent, the combustion temperature is high, the reaction process is fast, it is not easy to control, the product is easy to sinter, and there is a high possibility of non-equilibrium phase in the product or metastable phase; for the hydrothermal method, the safety performance is poor, the equipment requirements are high, the reaction cycle is long, and the energy consumption is large

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  • Method for preparing lanthanum cuprate (La2CuO4) powder by means of microwave-hydrothermal method
  • Method for preparing lanthanum cuprate (La2CuO4) powder by means of microwave-hydrothermal method

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Effect test

Embodiment 1

[0019] 1) Get 50ml distilled water and add in the beaker, then add analytically pure lanthanum nitrate (La(NO) in the beaker 3 ) 3 ·6H 2 O) magnetic stirring makes concentration be the solution A of 0.6mol / L;

[0020] 2) Add analytically pure copper nitrate (Cu(NO 3 ) 3 ·3H 2 O) stirring and making copper nitrate concentration is solution B of 0.3mol / L;

[0021] 3) press citric acid (C 6 h 8 o 7 ·H 2 O) and metal cation sum are 3: 1, add analytically pure citric acid (C) in solution B in the mol ratio 6 h 8 o 7 ·H 2 O) stirring at normal temperature to obtain solution C;

[0022] 4) Add ammonia water with a mass percentage of 4% to solution C dropwise, adjust the pH to 3, and stir for 30 minutes to obtain solution D;

[0023] 5) Add solution D into the microwave hydrothermal reaction tank, and control the filling degree to 70%; after sealing the reaction tank, place it in a microwave hydrothermal instrument; control the hydrothermal temperature at 200°C, react fo...

Embodiment 2

[0027] 1) Get 45ml distilled water and add in the beaker, then add analytically pure lanthanum nitrate (La(NO) in the beaker 3 ) 3 ·6H 2 O) magnetic stirring makes concentration be the solution A of 0.5mol / L;

[0028] 2) Add analytically pure copper nitrate (Cu(NO3 ) 3 ·3H 2 O) stirring and making copper nitrate concentration is solution B of 0.5mol / L;

[0029] 3) press citric acid (C 6 h 8 o 7 ·H 2 O) and metal cation sum are 2.8: 1, and in solution B, add analytically pure citric acid (C 6 h 8 o 7 ·H 2 O) stirring at normal temperature to obtain solution C;

[0030] 4) Add ammonia water with a mass percentage of 3% to solution C dropwise, adjust the pH to 1.5, and stir for 10 minutes to obtain solution D;

[0031] 5) Add solution D into the microwave hydrothermal reaction tank, and control the filling degree to 80%; after sealing the reaction tank, place it in a microwave hydrothermal instrument; control the hydrothermal temperature at 160 ° C, react for 60 minu...

Embodiment 3

[0034] 1) Get 60ml distilled water and add in the beaker, then add analytically pure lanthanum nitrate (La(NO) in the beaker 3 ) 3 ·6H 2 O) magnetic stirring makes concentration be the solution A of 0.7mol / L;

[0035] 2) Add analytically pure copper nitrate (Cu(NO 3 ) 3 ·3H 2 O) stirring and making copper nitrate concentration is solution B of 0.4mol / L;

[0036] 3) press citric acid (C 6 h 8 o 7 ·H 2 O) and metal cation sum are 3.8: 1, the mol ratio adds analytically pure citric acid (C in solution B) 6 h 8 o 7 ·H 2 O) stirring at normal temperature to obtain solution C;

[0037] 4) Add ammonia water with a mass percentage of 5% to solution C dropwise, adjust the pH to 5, and stir for 120 minutes to obtain solution D;

[0038] 5) Add solution D into the microwave hydrothermal reaction tank, and control the filling degree to 60%; after sealing the reaction tank, place it in the microwave hydrothermal instrument; control the hydrothermal temperature at 220 ° C, rea...

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Abstract

A method for preparing lanthanum cuprate (La2CuO4) powder by means of the microwave-hydrothermal method includes the following steps: lanthanum nitrate is added into distilled water, so that solution A is obtained; copper nitrate is added into the solution A, so that solution B is obtained; citric acid is added into the solution B, so that solution C is obtained; the pH of the solution C is regulated to 1.5 to 7, so that solution D is obtained; the solution D is added into a microwave-hydrothermal reactor, the reactor is sealed and then put into a microwave-hydrothermal instrument to carry out hydrothermal reaction, and after reaction is finished, the reactor is naturally cooled to the room temperature; sample is collected by centrifugal separation and then repetitively washed by distilled water and acetone, and after drying, the La2CuO4 powder is obtained. Since the method adopts the microwave-hydrothermal method to prepare the La2CuO4 powder, the electric field and the magnetic field can be changed in the space, so that molecular motion can be intensified, as a result, heat energy can be obtained, and thereby the synthesis of the La2CuO4 powder becomes highly efficient, simple and highly repetitive. Moreover, the heating speed is high, heating is uniform and does not have the temperature gradient and the hysteresis effect, consequently, the defect of ununiform heating of a hydrothermal container is overcome, the reaction time is shortened, energy consumption is reduced, and the working efficiency is increased.

Description

technical field [0001] The invention belongs to the technical field of high-temperature superconducting materials, in particular to a microwave hydrothermal method for preparing lanthanum cuprate (La 2 CuO 4 ) powder method. Background technique [0002] In superconducting materials, one expects to obtain the transition temperature T C High new materials, in order to achieve the purpose of large-scale application, this kind of research makes the superconducting system consist of elemental superconductors composed of initial metal elements, and expands to compound and alloy superconductors, organic superconductors, heavy fermion superconductors (composed of lanthanides or actinides) It is a compound composed of elements, its superconductivity is related to 4f electrons with large effective mass, and electrons are fermions, so it is called "heavy fermion superconductor") and other superconducting families with a wide variety and a large number. Among so many superconductors...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01G3/00
Inventor 黄剑锋李意峰刘佳曹丽云吴建鹏
Owner 山东格新精工有限公司
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