1. Preliminaries
The sand used to prepare mold (core) sand in the casting of titanium tube containers is called foundry sand, or raw sand for short. The quality of raw sand, moisture and mud content will directly affect the performance of casting sand and the quality of castings. Therefore, the relevant performance should be checked in production in order to properly select raw sand.
Raw sand properties are often tested for mud content, particle shape, sintering point, etc. Precise analysis of raw sand, such as chemical composition analysis method and ray method, is only carried out in a few factories.
The portion of the raw sand with a diameter less than 0.022mm is called the mud content of the raw sand.The particle size of the sand and mud suspended in the water is different, and the speed of their sinking in the water is also different. Sand and mud are separated.
The particle composition of raw sand includes particle size, ratio between different particles, particle shape and surface condition.It has a great influence on the strength, gas permeability, fluidity and plasticity of molding sand, and is important for judging the quality of raw sand. One of the indicators.
The particle size of raw sand and the ratio between different particles are usually determined by sieving, that is, the sand sample removed by the mud and dried is sieved with a set of standard sieves (11 sieves and 1 chassis).
2.the purpose of the experiment
(1) Through this experiment, master the method of measuring the mud content in order to select the raw sand correctly.
(2) Master the method of measuring the shape and surface condition of raw sand to control the quality of foundry sand, and choose raw sand reasonably.
3. Experimental principle and content
The experiment uses a continuous mud content measuring instrument for measurement.The principle is that the raw sand to be measured is placed in the flushing bottle, and the bottom of the rinse bottle is passed through a certain pressure of water (the pressure and pressure can be adjusted by the measured pressure relief valve and flow meter). Flow rate), in this way, the light weight mud is separated from the sand powder particles due to the difference in buoyancy and movement speed, and flows out through the upper part of the rinse bottle, continuously passing water until it is washed. The entire flushing process can be automated.
4. Experimental instruments and raw materials
One SLX continuous mud content tester, several beakers, one infrared oven, one balance (accuracy 0.01 g), one electric pan, one sand tray, one bottle of distilled water, one 5% sodium pyrophosphate solution Bottle, solid sodium pyrophosphate, raw sand (after washing and sieving), binocular stereo microscope.
