Process for synthesizing calcium zirconate by liquid-phase and solid-phase mixed calcination method

Abstract

The invention relates to a process for synthesizing calcium zirconate by a liquid-phase and solid-phase mixed calcination method. The process comprises the following steps of: 1, mixing zirconium carbonate or zirconium hydroxide and CaCO3 or Ca (OH) 2 in a metallic oxide molar ratio of 1:1.0-1.2 by using refined water; 2, performing centrifugal separation and dehydration on the slurry; 3, loading the dehydrated mixture into a quartz crucible, feeding the quartz crucible into a tunnel kiln of which the central highest temperature is between 850 and 1,200 DEG C, and slowly warming up; and 4, discharging, cooling, crushing, and packing to obtain finished products. The moisture content of the dehydrated materials is between 40 and 50 percent. By the process, the defects of nonuniform mixing, incomplete reaction, nonuniform particles and super high energy consumption by a dry method are overcome, and the process problems of difficulty in cleaning impurities, a large amount of wastewater, drying and the like by a wet method are solved. The whole production process has short flow and simple equipment, is easy to operate and control, is suitable for large-scale production, and has high product quality and lower cost.

Description

technical field [0001] The invention relates to a synthesis process of calcium zirconate, in particular to a process for synthesizing calcium zirconate by a liquid-phase mixed solid-phase calcination method. Background technique [0002] At present, the preparation methods of calcium zirconate mainly include solid-phase high-temperature synthesis. [3-4] ,Hydrothermal [5] and co-precipitation [6-7] . The solid-phase high-temperature synthesis method generally uses zirconia and calcium oxide as raw materials with a molar ratio of 1:1 for mechanical mixing, and then calcines the materials at a high temperature of 1400°C-1700°C; this method not only has high energy consumption, but also has a particle size distribution Broad, weak activity. The hydrothermal method is to mix calcium salt or calcium hydroxide with zirconium oxychloride (molar ratio 2:1), adjust the pH>12 with KOH, put it into the reactor for a certain period of time, filter and wash, dry and calcinate (900°...

AI Technical Summary

Problems solved by technology

The solid-phase high-temperature synthesis method generally uses zirconia and calcium oxide as raw materials with a molar ratio of 1:1 for mechanical mixing, and then calcines the materials at a high temperature of 1400°C-1700°C; this method not only has high energy consumption, but also has a particle size distribution Wide, weak activity

The hydrothermal method is to mix calcium salt or calcium hydroxide with zirconium oxychloride (molar ratio 2:1), adjust the pH>12 with KOH, put it into the reactor for a certain period of time, filter and wash, dry and calcinate (900°C- 1200℃) the quality of the calcium zirconate prepared is very good, but the requirements for the equipment are too high, the material waste is large, the cost is too high, and the scale production is unrealistic

Co-precipitation method is based on (NH 4 ) 2 C 2 o 4 Precipitated calcium, with NH 3 ·H 2 O precipitates zirconium to obtain mixed materials, which are also washed, dried and calcined, which is cumbersome and expensive.

From the current overall preparation method of calcium zirconate, it can be attributed to: high energy consumption, complicated operation, large amount of waste water, uneven particles, etc.