SU1509169A1 - Sand for manufacturing mould cores and moulds - Google Patents

Abstract

The invention relates to a foundry, in particular, to mixture compositions for the manufacture of foundry cores and heat-curable molds. The purpose of the invention is to improve the quality of the mixture by increasing its vitality while maintaining a high level of strength in the cured state, as well as improving sanitary and hygienic working conditions. The composition of the mixture, wt.%: Urea-formaldehyde binder 0.55 ... 3.95

natural bischofite 0,65 ... 2,05

quartz sand - the rest. The implementation of the invention makes it possible to increase the survivability of the mixture by an average of 3 times while maintaining high strength values in the cured state, as well as to improve the sanitary and hygienic working conditions by eliminating toxic phenol alcohol from its composition.

Description

The invention relates to a foundry, in particular, to mixture compositions for the manufacture of cores and heat curing forms.

The purpose of the invention is to improve the quality of the mixture by increasing its vitality while maintaining a high level of strength in the cured state, as well as improving sanitary and hygienic working conditions.

The essence of the invention is as follows.

The bischofite - magnesium sulphide magnesium chloride (MgCl2-6H2O) used in the proposed mixture is well soluble in water, is extracted from a field in the Volgograd and Saratov regions and has the following chemical composition, wt%;

MgCb84,032-86,658

MgBr21,504-1,551

CAC0,816-0,842

KS1 CasOZ SANSOz CaSO4 BaO Water

0.320-0.330 0.080-0.083 0.048-0.050 0.112-0.116 0.096-0.099 Else

The aqueous solution of natural bischofite introduced into the mixture in the specified amounts not only plays the role of a catalyst, but is also a mineral component of the complex binder and, while maintaining its physicomechanical and technological properties at a high level, replaces toxic phenol alcohol. The combination of a bischofite with a urea-formaldehyde resin contributes to a deep bonding polycondensation process and allows to obtain a high reactivity of the mixture during heat curing, high strength characteristics of the rods and shapes, increase the survivability of the mixture and improve sanitary and hygienic conditions.

01

about with

05

with

labor due to the absence of harmful secretions during thermal exposure to bishophyth.

example. The mixture is prepared as follows. A KF-MT resin is loaded into a paddle type mixer, bischofite is added, stirred for 3-5 minutes at 60-300 rpm, and held for 18-20 hours until a homogeneous solution of the complex bond is obtained. Then into the mixer

Claims (1)

Invention Formula A mixture for making casting cores and heat-curing forms, containing quartz sand, carbamide-formaldehyde binder, and natural bischofite, characterized in that, to improve the quality of the mixture by increasing its vitality while maintaining a high level of strength, the refractory filler is loaded in the cured state , interruptions, as well as improvements in hygiene and hygiene, mix for 30 seconds, add complex working conditions, the mixture contains the urea-formaldehyde resin and bischofite binder is mixed for 3-4 minutes, after which the mixture is ready for use. The compositions of the proposed mixtures are given in Table 5. one. The curing temperature of the rods and molds of the proposed mixture is 200-240 ° C. Properties of mixtures No. 1-3 (table. 1) are shown in table. 2.20 In tab. Table 3 shows the tensile strength values of the cured samples prepared from mixtures with different shelf life, which allows us to judge the viability of the proposed mixture. 25 From the data table. 3 it follows that the survivability of the proposed mixture averages 26 hours. The implementation of the invention will increase the survivability of the mixture by an average of 3 times while maintaining high levels of strength in the cured state, as well as improving the sanitary and hygienic working conditions by eliminating toxic phenol alcohol from its composition. the mentioned ingredients in the following ratio, wt.%: Urea formaldehyde binder 0,55-3,95 Natural bischofite0,65-2,05 Quartz sandEverything else Table 1 Invention Formula the mentioned ingredients in the following ratio, wt.%: Urea formaldehyde binder 0,55-3,95 Natural bischofite0,65-2,05 Quartz sandEverything else Table 1 Vitality, h Humidity,% Compressive strength in wet condition, MI a Tensile strength (limit) in the cured state, MPa Gas content, cm- / g. 23 25 25 1.2-1.6 2.0-2.5 2.5-3.0 0.004 0.004 0.004 3.7 10.5 3.8 13.0 Right after cooked no mixture four eight 12 14 18 22 26 thirty b l and c a 3 3.0 3.3 3.3 3.2 3.2 3.2 3.0 2.8 1.9