BVK plant, a member of KONAR group, put into service an area of thermal recovery of silica sands.
In order to get a steel casting of top quality, BVK founders use special lining molding chromite sand. This sand serves as material for the casting mold into which liquid metal is poured. Chromite sand is rare, it is produced only in South Africa. It is used for manufacturing of the mold layer that is in direct contact with the casting surface. In order to maintain its quality, BVK uses a special equipment for chromite recovery designed and supplied by the Italian company IMF. The rest volume of molds is filled with silica sand.
– During the technological process sand is mixed with special foundry resins and catalysts. The mold with this mixture becomes hard, after pouring of liquid steel and casting cooling it is completely destroyed and the silica sand goes to preparation for repeated usage. It is a world practice, – explains Deputy Chief Process Engineer BVK LLC Sergey Savateev.
After several cycles of such use non-cracked organic remains of polymerized resins are accumulated in the silica sand, and it has negative impact on the quality of molding mixture. In order to provide the required strength, quantity of resins has to be increased every time. At some point the quality of silica sand declines so much, its further application is impossible, and it has to be replaced for a new one.
In order to reduce costs for binding agents and sand as well as within the ecological policy of BVK LLC for decrease of environmental impact, in 2018 it was decided to reconstruct the molding area and to create a separate complex that will allow to carry out deep recovery of silica sands in order to restore the material up to its original state. KONAR team did great quantity of work. As a result, a complex area of thermal recovery of silica sands appeared. The “heart” of this area is a fluidized bed heat treatment furnace where remaining organic components of molding mixtures is removed at the temperature 500-700°C.
Due to this quality of silica sands increases almost to its original level, consumption of resins and sand stabilizes and increases in 2 times.
– There are few production facilities in Russia that use the same method of thermal sands recovery but application of such highly effective system for recovery of silica sands only makes BVK the unique in its way company in Russia, – notices Sergey Savateev.