Study On Technical Solution Of The Key Equipment For Total Reclamation Of The Used Clay Sand

Casting technology in China has a long history of development, our country is a great power early masters casting technique in the word. Sand mold casting has many advantages compared with other casting process, which plays an important role in castings production methods. In the production of castings on the word, more than80%of which are from the sand mold casting, and the clay sand mold in the application of cast proportion account for about85%. the amount of the used sand thrown away is very considerable. This is not only a huge waste of natural resources bust also a kind of pollution to our environment. This topic research can reduce the production cost and environmental pollution and save natural resources, and so there is a great significance to sustainable development of the foundry industry.According the earlier research it finds out that after high temperature baking, mechanically reclaiming and removing the micro powder, the reclaimed sand’s grain distributing is not changed too much and the grain shape is near round and the mud content is lower than that of the same base sand. The total reclamation sand instead of the same base sand to mix clay sand, hot-box resin sand, hot-box resin sand, coated sand and sodium silicate sand, the strength of the sand mold and core is able to meet the requirements of casting production. But at present the manufacturers specializing in the production of complete sets of equipment for complete regeneration of the used clay sand is small in our country, and the equipment applied to complete regeneration of the used clay sand has become the main obstacles restricting the popularization and application of the complete regeneration technology of the used clay sand in our country, for which we carry out the study on technical solution of the key equipment for total reclamation of the used clay sand, which provides a theoretical basis for the development of complete sets of equipment for complete regeneration of the used clay sand.Based on deeply understanding the development situation of the regeneration technology and equipment of the used clay sand which are introduced at home and abroad, this paper studis the process of sand block granulating, high temperature embrittlement, cooling, regeneration, removing the micro powder according theoretical analysis and experimental research, and on the basis of which determines the technical solution of the key equipment on the basis of the early research results.Through the experimental research on clay sand graining technology it can be found that the mass broken rate is improved to some extent along with the increase of the content of pellets in used clay sand and when the pellet content increases to a certain proportion the sand mass broken rate tends to be stable. After making pellets and sand separation and then for crushing grain, it can increase the rate of breakage.According to principle and structure analysis and summarizing the characteristics of the commonly used heating device to particle materials, this paper determines the high temperature embrittlement technical solution of the complete used clay sand regeneration. It puts a multiple tube heat exchanger on the device, the high temperature flue gas enter into the multiple heat exchanger making heat exchange with the work gas, which makes the flue gas temperature reduced and at the same time the work gas temperature improved and in the end improves the device’s thermal efficiency.This paper studies the impacts on the particle size and shape of silica sands by roasting times and different methods of cooling, which finds out that different methods of cooling may lead to different cooling rates of sands; that is, adopt water-cooled fluidized bed to cool down sands, the cooling rate is the highest; the secondary is by cooling cylinder, and common fluidized bed leads to the lowest cooling rate. After being roasted and cooled, no matter which method is adopted, the sands are not changed obviously in particle size and shape, which indicates that roasting times, different cooling methods and cooling rates have no obvious impacts on the particle size and shape of silica sands. The technical scheme that a fluidized bed with cooling water pipe is determined on the basis of theoretical research results for the cooling of the high temperature sand. Through the establishment of regeneration model the regeneration method suitable for complete regeneration of the used clay sand is studied, it finds out that upstream rotor reclaimer, grinding wheel reclaimer, air current reclaimer have the ability of being used for total used clay sand regeneration, and vibration reclaimer cannot be used for total used clay sand regeneration, on the basis of the study this paper makes more rows grinding wheel regenerator as the equipment for complete used clay sand regeneration.Using negative pressure fluidized bed and flow episodic winnowing machine to sudy the separation of the micro powder and sand, which finds out that negative pressure fluidized bed is able to achieve the purpose of complete separation of the micro powder and sand, and flow episodic winnowing machine can’t completely separate the micro powder and sand. Therefore, this paper determines a technology solution of the separation plant based on fluidized bed.