Bismuth oxide micro-powder and its preparation method

Abstract

The invention discloses a bismuth oxide micro-powder and its preparation method which comprises, charging bismuth nitrate solution containing 100-350g / L of Bi 3+ into ammonium hydrogen carbonate solution with concentration of 10-25 wt%, controlling the weight ratio of charged ammonium and bismuth between 1.5-3.5, producing bismuth carbonate precipitate while agitating at normal temperature, filtering and washing, carrying out thermal treatment for the filter cake at 100-700 deg. C, thus obtaining the bismuth oxide product, dispersing agent 0.1-5 wt% of the ammonium hydrogen carbonate solution can be charged.

Description

technical field [0001] The invention belongs to the field of bismuth oxide used in the electronic industry, in particular to high-purity bismuth oxide doped with materials for electronic components such as varistors, ceramic capacitors, dielectric ceramics, sensitive components, thermistors, lightning arresters, and picture tube glass bulbs Ultrafine micropowder and its preparation method. Background technique [0002] As a doping material for electronic functional ceramics, bismuth oxide powder not only has high requirements for its chemical composition, but also has some special requirements for its physical properties such as crystal structure, morphology, agglomeration state, particle size, particle size distribution, and specific surface area. Require. [0003] The existing bismuth oxide production methods include fire method and wet method. One of the pyrotechnics is to oxidize molten metal bismuth at high temperature in the presence of oxygen to form bismuth oxide a...

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Problems solved by technology

One of the pyrotechnics is to oxidize molten metal bismuth at high temperature in the presence of oxygen to form bismuth oxide and then pulverize it. This process is easy to introduce impurities during the crushing process; the second pyrotechnic is to use plasma heating technology to produce 10μm bismuth oxide. This process must have a microwave regenerator and a vacuum device, the investment and energy consumption are large, the process is complicated, and the production cost is high; the third of the fire process is to dissolve the refined bismuth in nitric acid, heat and concentrate to evaporate into bismuth nitrate crystals, Calcined in the muffle furnace to catch up with the nitrate, it becomes fragmented bismuth oxide, and then crushed and screened to produce bismuth oxide powder. The disadvantages of this process are: 1. During the process of concentration, evaporation and calcination, a large amount of nitrogen is produced Oxide waste gas pollutes the environment and endangers the health of operators. Second, the calcined bismuth oxide fragments generate a large amount of dust during crushing and screening, which pollutes the site and causes the recovery loss of bismuth oxide. Third, during ball milling, some ceramic ball powder enters the In bismuth oxide, it affects the quality of the product

[0014] The above methods either cause serious environmental pollution, or have complex processes, or have high impurity content, or low yields, and there are certain problems in the industrial production process.

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