SU621442A1 - Solution for processing refractory filler - Google Patents

Description

one

The invention relates to the field of foundry and can be applied to the surface treatment of refractory fillers of foundry mixtures, such as silica sand, in the manufacture of shell cores and molds, providing an increase in their strength properties in the cured state.

Various solutions are known for treating refractory fillers. casting mixtures that provide an increase in heat resistance, for example, a weak solution of an organic base and / or 1CRT.

However, when working with such solutions, care must be taken, and intensive gas release when using them worsens the sanitary and hygienic working conditions.

Chemical treatment of the surface of quartz sands with an aqueous solution of hydrochloric acid is known.

The disadvantages of such a solution are the danger of using in the production of hydrochloric acid, the duration of the process, a slight increase in the strength of the mixture with the filler.

Known processing refractory filler with an aqueous solution of surfactants, including those from the group of phosphates.

However, the molding mixture with a filler treated with this solution does not increase the strength of the mixture on the resin binder while reducing its content in the mixture.

In order to increase the strength properties of the mixtures and shorten the technological cycle of the surface treatment of the filler, the solution for treating the refractory filler containing water and the phosphate compound contains the ammonium salt of phosphoric acid as the latter. As the specified salt, the solution may contain phosphate dibasic ammonium in the following co-bearing ingredients, weight ..:

Water 68-7.5

Ammonium salt

Claims (2)

phosphoric acid 25-32 The solution is prepared as follows. The ammonium salt of phosphoric acid is added to the water and mixed by ordinary stirring. dissolve to obtain a homogeneous transparent liquid. To accelerate the dissolution, the water is preferably heated. Up to 50-60 ° C. The filler is processed in the usual way. Before drying, the top-up filler is filled with 0.8-1.2% by weight of the prepared composition and mixed for 4-5 minutes until evenly distributed. Any bulk material mixer can be used for mixing. Thereafter, the treated filler is usually sent to the kiln on an orderly basis in the kiln for drying and further along the entire technological chain for preparing the mixture. After drying, neutralization of the harmful effect of clay, various oxides, carbonates and other impurities occurs. As a result, the adhesion between the binder and the surface of the filler increases, resulting in an increase in the strength properties of the hardened mixture. Formulations 1 were prepared with the composition of the lower, middle, and vertical limits of the content of the component. Dog; i 23 Water75. 70 68 Phosphate dibasic ammonium 25 30 32 These compositions in an amount of 1 wt.% Were introduced into quartz sand of the brand KO2A, from which a mixture with 4 wt.% Bonding PC-104 was prepared. From the obtained mixtures, eight specimens were made, the tensile strength of which was respectively 24.9; 25.5; 25.0 kgf / cm. The strength of the rods and fzrm of the mixture on pulverololite (4 wt.%) Increases by 30–40%. This increase in strength allows a corresponding reduction in the consumption of the scarce and expensive Binder in the mixture, thereby reducing gas clearance, improving the sanitary and hygienic conditions of the pipe and reduce the cost of the mixture. The proposed solution can be used without special protection. Claim 1, Solution for treating refractory filler used in molding and core mixtures, containing water and phosphate compound, characterized in that the solution contains ammonium salt as a phosphate compound in order to increase the strength of mixtures and reduce the technological cycle of the surface treatment of the filler. phosphoric acid in the following ratio of ingredients, wt.%: 68.0-75.0 Ammonium phosphate salt 25.0-32.0 acid 2. A solution of pop. 1, which differs from the fact that, as the ammonium salt of phosphoric acid, it contains phosphate dibasic ammonium.