Abstract: The present application relates to a method for preparing L-methionine crystals with an improved bulk density. As the L-methionine crystals prepared according to the method for preparing L-methionine crystals of the present application may have a bulk density of up to 800 g/L, the L-methionine crystals are expected to reduce storage and transport costs of L-methionine powder and improve working conditions due to improved fluidity of the powder.

Abstract: In a system for recycling a high-boiling-point waste photoresist stripper generated in processes of manufacturing LCDs or semiconductor devices, wherein an expensive high-boiling-point stripper solvent can be easily recycled at high yield and high-purity electronic grade. This system includes a first distillation device for removing low-boiling-point impurities, a second distillation device for recycling a stripper solvent composition while removing high-boiling-point impurities, a third distillation device for removing trace water, thus recovering the stripper solvent composition, a fourth distillation device for additionally recycling a stripper solvent, thus additionally recovering a high-boiling-point stripper solvent, and a fifth distillation device for sequentially and separately recovering the stripper solvent composition recovered by the second distillation device and the high-boiling-point stripper solvent additionally recovered by the fourth distillation device.

Abstract: In a system for recycling a high-boiling-point waste photoresist stripper generated in processes of manufacturing LCDs or semiconductor devices, wherein an expensive high-boiling-point stripper solvent can be easily recycled at high yield and high-purity electronic grade. This system includes a first distillation device for removing low-boiling-point impurities, a second distillation device for recycling a stripper solvent composition while removing high-boiling-point impurities, a third distillation device for removing trace water, thus recovering the stripper solvent composition, a fourth distillation device for additionally recycling a stripper solvent, thus additionally recovering a high-boiling-point stripper solvent, and a fifth distillation device for sequentially and separately recovering the stripper solvent composition recovered by the second distillation device and the high-boiling-point stripper solvent additionally recovered by the fourth distillation device.

Abstract: In a system and method for recycling a high-boiling-point waste photoresist stripper generated in processes of manufacturing LCDs or semiconductor devices, an expensive high-boiling-point stripper solvent can be easily recycled at high yield and high-purity electronic grade.

Abstract: The present invention relates to a preparation of iron(II) acetate powder from low grade magnetite and comprises the following steps: (a) adding organic acid to low grade magnetite powder to obtain iron solution; (b) adding hydroxide to the iron solution to obtain iron hydroxide; and (c) adding acetic acid to the iron hydroxide, thereby obtaining iron(II) acetate. According to the present invention, it is possible to obtain high purity iron(II) acetate using low grade magnetite and there are advantages of mass producible environmentally-friendly simple process and prevention of corrosion of facilities.

Abstract: The present invention relates to a preparation of iron(II) acetate powder from low grade magnetite and comprises the following steps: (a) adding organic acid to low grade magnetite powder to obtain iron solution; (b) adding hydroxide to the iron solution to obtain iron hydroxide; and (c) adding acetic acid to the iron hydroxide, thereby obtaining iron(II) acetate. According to the present invention, it is possible to obtain high purity iron(II) acetate using low grade magnetite and there are advantages of mass producible environmentally-friendly simple process and prevention of corrosion of facilities.