Regeneration technology of foundry used sand

Abstract

The invention relates to a regeneration technology of foundry used sand. The technology comprises the following steps that (1), initial magnetic separation is carried out on broken used sand; (2) the broken used sand obtained after initial magnetic separation is roasted; (3), roasted sand grains are cooled, and under the negative pressure condition, blast grinding is carried out on the sand grains; and (4), the ground sand grains are screened, magnetic separation is carried out again, and regeneration sand is obtained. The quality of the regenerated sand obtained through the technology treatment is further improved, the acid consumption value and the ignition losses of the sand are obviously reduced, the sand grain and the resin coating effect is better, the strength is higher, the pollution of the used sand to the environment is reduced, the cost of core making materials of a casting enterprise is saved, and a hot core box and a cold core box made of original sand can be completely replaced.

Description

technical field [0001] The invention relates to a regeneration process of used casting sand, which belongs to the technical field of recycling foundry used sand. Background technique [0002] In the existing foundry sand regeneration process, magnetic separation is usually performed before roasting to remove magnetic substances. However, the residual organic matter contained in the old foundry sand affects the magnetism, making it difficult to completely remove the magnetic substances. At the same time, the inventors of the present application have found in research that during the follow-up high-temperature heat treatment process, a layer of iron film is often adhered to the surface of the sand grains, and there are small iron beads in the tiny pores inside the sand core (type); therefore, now The reclaimed sand obtained by the foundry old sand regeneration process is of poor quality, which still contains a large amount of magnetic impurities. However, due to the existence...

AI Technical Summary

Problems solved by technology

[0002] In the existing foundry sand regeneration process, magnetic separation is usually performed before roasting to remove magnetic substances, but the residual organic matter contained in the old foundry sand affects the magnetism, making it difficult to completely remove the magnetic substances

At the same time, the inventors of the present application have found in research that during the follow-up high-temperature heat treatment process, a layer of iron film is often adhered to the surface of the sand grains, and there are small iron beads in the tiny pores inside the sand core (type); therefore, now The regenerated sand obtained by the foundry old sand regeneration process is of poor quality, which still contains a large amount of magnetic impurities

However, due to the existence of these magnetic impurities, the acid consumption value in the process of preparing cold or hot cores from reclaimed sand is relatively large, which affects the effect of cold core catalysts and the coating effect of sand particles and resin, and reduces the strength of sand cores. Fully used in the manufacture of hot and cold boxes

Images