Magnesium oxide particle aggregate

A particle aggregation, magnesia technology, applied in magnesia, furnace type, furnace, etc., can solve problems such as insufficient reaction

Inactive Publication Date: 2003-07-02
TATEHO CHEM IND CO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

That is, even if magnesium oxide particles have an active surface, if the number of contacts ...

Method used

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  • Magnesium oxide particle aggregate
  • Magnesium oxide particle aggregate
  • Magnesium oxide particle aggregate

Examples

Experimental program
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Effect test

Embodiment 1

[0063] The magnesite is roasted at 850°C for 1 hour in a rotary kiln, and crushed into magnesium oxide with a cage crusher. In order to control the particle structure, magnesium oxide is added to water so that the concentration of magnesium hydroxide after the reaction is 3mol / kg, stirred at 400rpm, and reacted at 85-95°C for 2 hours to generate the precursor magnesium hydroxide. After the generated magnesium hydroxide is filtered with a filter press, washed with water and dried, the obtained magnesium hydroxide is roasted in a rotary kiln at 900°C at 22°C with a final reaction rate of 40% citric acid activity in the range of 120-140 For 1 hour, it is baked to form magnesium oxide particle aggregates. Then, it was pulverized with a hammer mill at a hammer rotation speed of 3500 rpm and a classifier rotation speed of 3000 rpm to produce magnesium oxide particle aggregates having a predetermined particle aggregation structure.

Embodiment 2

[0065] The calcium hydroxide slurry was added into the brine so that the concentration of the reacted magnesium hydroxide was 2 mol / kg, stirred at 600 rpm, and reacted at 80° C. for 2 hours. Then, filter, wash, and dry the magnesium hydroxide with a filter press, use a rotary kiln at 890°C for 1 hour at 22°C and a citric acid activity of 40% at a final reaction rate of 120 to 140 for 1 hour. It is an aggregate of magnesium oxide particles. Then, the powder was pulverized by a pulverizer at a hammer rotation speed of 3500 rpm and a classifier rotation speed of 4000 rpm to produce a magnesium oxide particle aggregate having a predetermined particle aggregation structure.

Embodiment 3

[0067] Calcium hydroxide slurry was added to magnesium chloride, so that the concentration of magnesium hydroxide after the reaction was 1mol / kg, and then 10ppm coagulant polyaluminum chloride was added, stirred at 400rpm, and reacted at 60°C for 20 hours. Then, filter, wash, and dry the magnesium hydroxide with a filter press, use a rotary kiln at 900°C for 1 hour at 22°C and a citric acid activity of 40% at a final reaction rate of 120 to 140 for 1 hour. It is an aggregate of magnesium oxide particles. Then, the powder was pulverized with a pulverizer at a hammer rotation speed of 3200 rpm and a classifier rotation speed of 4000 rpm to produce a magnesium oxide particle aggregate having a predetermined particle aggregation structure. Comparative example 1

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Abstract

An object of the present invention is to provide a magnesium oxide particle aggregate having a controlled particle aggregation structure so that the solid phase-solid phase reaction between magnesium oxide and the SiO2 film on the surface can be appropriately controlled. The object can be achieved by a magnesium oxide particle aggregate characterized in that a first inflection point diameter is 0.30 x 10<-6> m or less, an interparticle void volume is 1.40 x 10<-3> to 2.20 x 10<-3> m<3>/kg and a particle void volume is 0.55 x 10<-3> to 0.80 x 10<-3> m<3>/kg in a cumulative intrusion volume curve of the particle aggregate.

Description

technical field [0001] The present invention relates to an aggregate of magnesium oxide particles for controlling particle aggregation structure, and in particular, relates to an aggregate of magnesium oxide particles for an annealing separator that forms a forsterite thin film that imparts excellent insulating properties and magnetic properties to a grain-oriented electrical steel sheet. Background technique [0002] The grain-oriented electrical steel sheets used in transformers and generators are generally processed by hot-rolling silicon steel containing about 3% Si, then cold-rolling to the final plate thickness, and then decarburization annealing (primary recrystallization annealing), finishing annealing and other processes made. At this time, in order to impart insulation to the electrical steel sheet, a slurry containing magnesia is applied to the surface of the steel sheet after decarburization annealing, dried, wound into a coil, and then final finish annealing is ...

Claims

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Application Information

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IPC IPC(8): C23C22/00C01F5/02C21D8/12H01F1/18
CPCC01P2006/14C01P2006/16C21D8/1283H01F1/18C01F5/02C01P2004/50C01P2004/40C23C22/00
Inventor 平津丰清川敏夫东塚淳生
Owner TATEHO CHEM IND CO
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