RU2000172C1 - Method for powdering of rejected sintered articles from manganous-zinc ferrites - Google Patents

Description

powder exceeds their activity during subsequent sintering.

Example 1. The proposed and known methods for preparing powder from defective sintered products of Mn-Zn ferrite grade 25000НМС2 were tested. W12x20 products were heat-sealed by quenching in running water from a temperature of 1000 ° С followed by wet grinding in ball mills СМ6007А. Polyacrylic acid (PAA) TU 6-01-1260-81 was introduced into the suspension during wet grinding. The specific surface of the powders obtained by drying the suspension samples was measured on an ADP-4 instrument. The data are given in table 1.

As can be seen from the data given in the table, the introduction of PAA in an amount of 0.05 mass% or more into the mixture during wet grinding accelerates the grinding intensity. However, when introduced in excess of 0.2 wt.%, Saturation is achieved in the grinding rate,

Example 2. The proposed and known methods for preparing powder from defective sintered products of Mn-Zn ferrite grade 200 NM were tested. SHYuHYu products were heat-resistant by quenching in running water with a temperature of 1000 ° С followed by wet milling in ball mills СМ6007А. 0.1 wt.% PAA was added to the suspension during wet grinding by the proposed method. By spraying the suspension on a Buran granulation dryer, powders were obtained which were subsequently oxidized in air by calcination in a Granule rotary kiln.

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a pipe. Of the oxidized powders and the powder according to the prototype, NI Ox 10 products were pressed and burned in furnaces with Hyperbol gas at 1300 ° C. The activity of the powders was evaluated by the value of the coefficient of shrinkage and density of the products after firing. The data on the effect of the temperature of powder oxidation on the shrinkage coefficient and density of products ШУх 10 are given in Table 2.

As can be seen from the table, at an oxidation temperature of less than 600 ° C, the required activity of the powder is not achieved, which is associated with insufficient oxidation, and at temperatures above 700 ° C, partial sintering of particles begins, which also reduces the activity of the powder during subsequent sintering.

Therefore, the maximum activity of the powder is ensured under the conditions of the proposed method, which allows to achieve a satisfactory density of the products after sintering.

Claims (1)

The claims A method of manufacturing a powder from defective sintered articles of manganese-zinc ferrites, including thermal hardening, subsequent wet grinding and drying the resulting suspension in a drying-granulation plant, characterized in that, in order to increase the specific surface area and activity of the obtained powder, wet grinding is carried out with by adding 0.05-0.2 wt.% polyacrylic acid based on the weight of the powder, and after drying, the powder is oxidized in air at 600-700 ° C. Table 1 table 2