Specifications for Ceramic Foundry Sand
Regarding foundry sand, people all wish to choose those with high refractoriness, small thermal expansion, and perfect round shape. Artificial sand,
rather than natural sand, could better meet these requirements.
Main Chemical Composition
pH
7.6-7.8
Shape
Sphere, Angle Factor ≤ 1.1
Refractoriness
1825℃
Thermal Expansion Rate
0.13% (10 minutes under 1000℃)
Mineral Phase
Mineral Phase: Mullite Phase≥85%, Corundum phase + Glass phase ≤15%
Bulk Specific Weight
1.95~2.05(g/cm³)
Mohs hardness
7.5-7.8
Production Process of Ceramic Sand
01
Raw aluminum cores contains lots of free water, crystal water, and low melting point components. Using raw aluminum cores to produce consumes large amount of electric energy and it is difficult to eliminate low melting point components, causing the instability of the product and affecting product quality. So it is important and essential to calcine the raw aluminum cores and use wrought aluminum cores (so called bauxite) as main material.
The percentage of Al2O3 in wrought aluminum is different from time to time. To keep the stability of Al2O3 and other minor elements and to insure the mineral phase to be Mullite phase, we need to homogenize bauxite.
The size of the bauxite varies a lot. For easy fusion and easy transportation, the bauxite needs to be atomized into pieces ranging from 30mm to 100mm and process another round of homogenization.
04
The bauxite, as a kind of refractory, could stand for over 2000oC, so we must use electric arc melting to fuse it, by applying low voltage and strong current. The fusing voltage should range from 85V to 130V and the temperature should be over 2200oC. Then the melt mineral liquid forms spherical particles, through the blow of high-pressure air. The pressure of air should be 0.4MPa – 0.5MPa. In the cooling process of forming spherical particles, to avoid cooling pressure, we use slowing cooling and change the structure of the nozzle, so we could get expected size distribution.
05
The traditional screening method for foundry sand is called three-screening method, which means that the concentration of three consecutive sieves is more than 75%. But this could not satisfy the need of the ceramic Sand, which is concentration of single sieve is more than 85%, and residual of two consecutive sieves is less than 15%. Because of the negative effect from the aluminum carbonate fiber and iron, the result of the screening is as follows:14Mesh: 0.141mm，70Mesh: 0.212mm，20Mesh: 0.85mm，100Mesh: 0.153mm，30Mesh: 0.6mm，140Mesh: 0.105mm，36Mesh: 0.425mm，200Mesh: 0.073mm，50Mesh: 0.3mm，Over 200Mesh.
Because of the grain shape of the spherical sand, the combination of the ceramic Sand follows normal distribution. Based on the requirements of AFS, different size of the ceramic Sand is mixed and stirred.
07
Testing in the screening process: Spot check every mesh number of the ceramic Sand, to make sure that the single sieve mesh number concentration meets the requirement. Also test the running situation of the equipment.Testing of the mixed sand: Apply scientific sampling method to test whether the residual in each mesh number meets the requirements.Currently, we mainly provide the following size of the ceramic Sand: AFS20, AFS25, AFS30, AFS40, AFS65, AFS75, AFS90, AFS100, AFS125, AFS180, or other customized sand based on customers’ request.
Product Features
Regarding product quality as the life of the enterprise, paying close attention to product quality, we do the best we can for the customers. All meshes of products produced by the company can fully meet the needs and requirements of customers for products.
High refractoriness
≥1825℃, same level with magnesite and chromite sand, and higher than silica sand, with less sand burning.
Low breakage rate
Moh's hardness of ceramic foundry sand being 7.8, and the spherical shape, make it hard to break ceramic sand
Good spherical shape
The shape of ceramic foundry sand is spherical and the angle factor is less than or equal to 1.1. With smooth surface and perfect shape, Ceramic foundry sand has smallest superficial area, making the volume added to adhesive and curing agent much less (average 40% - 50% less). So application of Ceramic foundry sand could lower the production cost, reduce exhaust emission, and improve casting environment. The spherical shape is also beneficial to the gas emission of pouring process and also reduce the porosity in castings. With the reduction of adhesive could also help to lower the strength of the casting model and the recycle of the sand.
Low expansion rate
Better than magnesite, chromite sand and silica sand, could meet higher accuracy requirement.
pH: 7.6 – 7.8
As a neutral material, Ceramic Sand is suitable for different kinds of alkalinity or acidity adhesive. For example: water glass, clay, resin curing agent.
Proportion
As a kind of special artificial sand, the bulk specific weight of ceramic foundry sand is smaller than magnesite and chromite sand. The reduction of the casting model and increased ratio of the iron sand will help to lower the production cost.
Pollution-free
Compared to the radioactivity of zircon sand and the pollution of chromite sand (some countries have forbidden the use of chromite sand), ceramic foundry sand is a more environmental friendly material, with higher re-use ratio and lower discharge.
Application Area
Application in production of steel castings
The scab phenomenon is quite common and serious in large scale steel castings, which affects the surface quality of the castings and bring lots of trouble in cleaning.
Application in the production of engine castings
In the core of engineer casting oil passage and water passage,the use of ceramic foundry sand could reduce the gas emission and porosity,
Hydraulic Pressure Casting
Similar with engine casting.
Stainless Steel Casting
The features of ceramic foundry sand is especially significant in the casting of resin sand. Many renowned companies, such as Japan Mucun Casting, Shou Casting,
Application in smelting industry
In iron and steel smelting industry, ceramic foundry sand is also used more and more commonly as the stuffing sand in molten steel refining.
Application in other industries
ceramic foundry sand could also be used in abrasive blasting in steel rust removal, surface cleaning for nonferrous castings and furniture.
Recycle and Re-use of Ceramic Foundry Sand
The recycled use of ceramic foundry sand is as follows
Recycle of used sand.
Magnetic Separation and Roasting for Used Sand
Screening and Matching for Used Sand
Luoyang Ruiyu Ceramic Sand Co.,Ltd.
Tel: 86-379-65110927 +86-16462178325
Fax: 86-379-65110921
Email: lyry@lyruiyu.cn
Website: www.foundry-sand.cn www.lyruiyu.cn
Address: Gaolong Town, Yanshi county, Luoyang, Henan, China
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