Introduction of silica sand-Jiangsu Juyang Precision Modeling Material Technology Co., Ltd.

Introduction of silica sand

Source：http://www.jsjuyang.cn/ Release time：2019-12-29 Visits：1

I. Overview Since the day when humans began to master casting technology, the modeling materials used have been based on silica sand. The application of castings in various aspects has promoted the progress and development of civilization and the emergence of the industrial revolution. Since then, with the rapid development of science and technology, various new materials have continuously emerged, and the casting process technology has also changed with each passing day. However, today, in the foundry industry around the world, silica sand is still the most important modeling material. At present, the raw sand consumed by the world's foundry industry each year is 45 billion 50 million tons, of which the proportion of silica sand is more than 95%. The most desirable aspect of silica sand is that it has abundant reserves, is cheap and easy to obtain, which is unmatched by any other ore sand. In addition, silica sand also has some characteristics that can adapt to the casting conditions, such as:

(1) It has a sufficiently high fire resistance and can withstand the effect of the casting temperature of most casting alloys.

(2) The particles are relatively hard, and can withstand the effects of rubbing and compression during molding and the impact and friction during regeneration of old sand.

(3) At high temperatures close to its melting point, there is still enough strength to maintain its shape.

However, silica sand also has many shortcomings, especially when the old sand is recycled, the silica sand is relatively easy to crack, and the dust generated by the cracking is very harmful to human health, which has gradually become the fatal weakness of the silica sand. With the increasing requirements for the quality of castings and the increasingly strict regulations on environmental protection and clean production, "silica sand is not the ideal raw sand" has gradually become a consensus, and seeking alternative materials for silica sand has become an important issue in the current casting industry. For one, all industrial countries attach great importance to this. One of the ways to find a substitute for silica sand is to use a suitable natural non-silica sand. Another way is to develop artificially manufactured granular materials. This article will make a brief review of the development of these two approaches, and put forward some preliminary ideas for the promotion and application of artificial sand in China's foundry industry. In the process of industrial modernization, the foundry industry has been exploring the application of non-siliceous sand for nearly a century. The application of various non-siliceous sands has a very important effect on the progress of casting technology and the improvement of casting quality. However, due to the impact of resource conditions and certain constraints, so far, on the one hand, no natural non-siliceous sand has the possibility of replacing silica sand on a large scale; on the other hand, from the perspective of the current technological development trend, The replacement of non-siliceous sand with various man-made materials has been included in the research and application agenda. The development and application of various artificial sands have also experienced more than 50 years of development. In the past ten years or more, the application of artificial sand has gradually shown its advantages in improving the quality of castings, reducing silicon dust pollution, and saving resources.All the types of "sand" related industries in the foundry industry have paid more and more attention to artificial Application of sand. In terms of special casting technology, artificial sand not only has a good effect in the V method modeling and lost foam casting application, but also replaces zircon sand in the surface refractory in investment casting, which has also become a hot research topic. . In sand casting, artificial sand is not only suitable for resin-bonded sand, but also replaces silica sand in wet clay sand. There are also many successful examples. Heat treatment / forging / casting No. 19 of 2011 Hot processing www.metalworking1950.com Casting material technology 9opicalReviewT special review In different casting alloys, artificial sand is not only suitable for the production of steel castings, but also for cast iron and non-ferrous alloy castings. According to the author's insights and superficial understanding, the possibility of large-scale replacement of silica sand with artificial sand has now fully appeared. Of course, the process of gradual promotion will be quite long, and there is still a lot of work to be done by colleagues in the casting industry.

Second, the application of non-siliceous sand Natural non-siliceous sand used in the foundry industry, mainly forsterite sand, aluminum silicate sand, zircon sand and chromite sand.

1. The application of forsterite sand is much earlier. In 1927, Norway, which is rich in forsterite, was first used to formulate molding sand for the production of steel castings. In the case of very poor early protection conditions, the use of this raw sand can prevent workers from suffering from silicosis, and it is used to produce high manganese steel and high chromium nickel steel castings, which can significantly improve the surface quality of the castings. However, this kind of sand is made from broken ore rock, with poor grain shape, cleavage and development, easy to break, molding sand is difficult to recycle, it is not suitable for regeneration treatment, and the price is several times that of silica sand. These are the two main reasons that restrict its promotion and application.

2. Aluminum silicate sand Aluminum silicate sand includes sand grains with minerals such as kyanite, sillimanite and andalusite. In natural minerals, the three often coexist, their crystal structures are different, and their chemical composition is the same (Al2O3SiO2), which is a homogeneous polymorphic variant

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