SU1335366A1 - Method of preparing binder for making casting ceramic moulds by investment patterns - Google Patents

Abstract

The invention relates to foundry, in particular, to methods for preparing liquid glass binders used in the manufacture of ceramic molds for produced models. The purpose of the invention is to intensify the process of making ceramic molds by reducing the binder preparation time. According to the invention, a calculated amount of water required to dilute liquid glass (LF) with an initial density of p to 40 ± 0.02 g / cm is previously introduced into orthophosphoric acid, and is neutralized with the indicated LL acid by stirring them for 1- 3 minutes followed by the transfer of the resulting body to a soluble state by continuing stirring for 10-20 minutes. Due to the described method, the process of preparing the liquid glass binder is reduced by 9-12 times. This makes it possible to combine the preparation of a liquid-glass binder and the preparation of a binding suspension on its basis in a single mixing unit. 1 tab. i 9 (L SAE OO SL OO O5 O5

Description

The invention relates to a foundry, in particular, to methods for preparing liquid glass binders for producing castings by the method of precise casting.

The aim of the invention is to intensify the process of making ceramic forms by reducing the duration of binder preparation.

The preparation of the binder according to the proposed method is carried out as follows.

The choice of the initial concentration of orthophosphoric acid is made by calculating it using the formula

/ C 1.5-1.4 (M-2.4),

where K is the required concentration of H3DD, mol / l;

M is the modulus of the original iron glass.

Next, the amount of water required to dilute the liquid glass of the initial density (1.45-1.48 g / cm) to a working density of 1.40 ± 0.02 g / cm is determined by calculation. With this calculated amount of water, orthophosphoric acid is diluted with a concentration of K-obtained acid solution and the initial (undiluted) water glass is neutralized by stirring them for 1–3 minutes. In this case, a gel is formed in the liquid glass, which dissolves in it when it is moved.

Example. Liquid glass in the amount of 1 kg has an initial density of 1.48 r / CNj and M 2.8. The concentration is determined by calculation from 1.5-1.4 (M.-2.4) 0.94 mol / l, which corresponds to 9 May. %

By using the proposed method, the process of preparing a liquid-glass binder is reduced by a factor of 9-12. This allows the treatment of liquid grade.

It is also calculated by calculation the amount of water that must be added to 1 kg of liquid glass with a density of 1.48 g / cm to obtain a liquid glass with a density of 1.40 + 0.02 g / cm. This amount of water is 0.2 kg.

The amount of 9% orthophosphoric acid is determined from the ratio

3 (yVi +) 10

where n

five

the amount of the original liquid glass (1 kg);

NI is the calculated amount of water needed to dilute the source liquid glass to a density of 1.40 ± 0.02 g / cm (0.2 kg). Substituting the corresponding values in the formula, we find that the amount of 9% HzPO is 0.36 kg. 0.26 kg of () water is added to 0.36 kg of 9% PWD4; 0.56 kg of HZPO solution with a concentration of 0.6 mol / l or 5.8 may be obtained. %

A prepared 5.8% acid solution, taken in an amount of 0.56 kg, is treated with 1 kg of initial liquid glass with a density of 1.48 g / cm. The treatment is performed by introducing the acid solution into the liquid glass for 2.5 minutes, with continuous stirring. A gel is formed, the time for which it can be reversed when transferred is 20 minutes. Prepared by the proposed method, liquid glass has, 6 and a density of 1.3 g / cm.

The table shows examples of the preparation of a liquid glass binder by the proposed method.

five

0

directly in the mixer to prepare the binder suspension due to the possibility of combining the treatment process (dilution and neutralization) of the liquid

glass and preparation of a binding suspension based on it.

Claims (1)

Invention Formula A method of preparing a binder for the manufacture of casting ceramic molds according to the models produced, including diluting with water and neutralizing liquid glass with orthophosphoric acid, characterized in that, in order to intensify the process of making ceramic forms by reducing the duration of preparation of the binder, water is first introduced into orthophosphoric acid in an amount necessary to dilute liquid glass to a density of 1.40 ± 0.02 g / cm and neutralization of liquid glass is carried out by transferring it within 1-3 minutes with the resulting solution, orthophosphoric acid and then converting the resulting gel into soluble state while continuing to move for 10-20 minutes.