US 11,987,867 B2
Recycling method for manufacturing high speed steel master alloy from high speed steel processing process waste
Bae Gyun Kim, Incheon (KR); and Kyeong Sik Kang, Incheon (KR)
Assigned to T&E INC., Incheon (KR)
Appl. No. 18/035,561
Filed by T&E INC., Incheon (KR)
PCT Filed Jun. 3, 2021, PCT No. PCT/KR2021/006909
§ 371(c)(1), (2) Date May 5, 2023,
PCT Pub. No. WO2022/119063, PCT Pub. Date Jun. 9, 2022.
Claims priority of application No. 10-2020-0167768 (KR), filed on Dec. 3, 2020.
Prior Publication US 2024/0011133 A1, Jan. 11, 2024
Int. Cl. C21C 7/072 (2006.01); C22B 1/00 (2006.01); C22C 33/06 (2006.01)
CPC C22C 33/06 (2013.01) [C21C 7/072 (2013.01); C22B 1/005 (2013.01)] 3 Claims
OG exemplary drawing
 
1. A recycling method of preparing a high speed steel (HSS) master alloy from wastes of HSS processing process, comprising:
a pre-treating step of pre-treating the wastes of the HSS processing process;
a primary melting step of forming a primary melt by primarily melting the pre-treated wastes of the HSS processing process at 1500 to 1700 degrees Celsius (° C.) in a melting furnace;
a purifying step of moving the primary melt to a holding furnace and degassing the primary melt and purifying impurities of the primary melt;
a preparing step of preparing the HSS master alloy by ingot casting the primary melt purified in the purifying step; and
wherein the pre-treating step includes:
a separating step of separating the wastes of the HSS processing process having a HSS process sludge, a HSS turning scrap, and a HSS scrap; and
a mixing step of forming a mixture by mixing oxides containing K2O, Al2O3, and SiO2 and the separated wastes of the HSS processing process with each other, the mixture having a melting point of 800 to 1700° C.,
wherein a molar ratio of K2O:Al2O3:SiO2 contained in the mixture is 1:1:2 to 1:1:6,
wherein the primary melting step of being performed in a vacuum atmosphere or an inert gas atmosphere during 1 hour to 8 hours,
the primary melting step of being performed by sequentially charging a portion of the HSS scrap, a portion of the mixture, a portion of the HSS turning scrap, a remaining amount of the mixture, a remaining amount of the HSS turning scrap, and a remaining amount of the HSS scrap into the melting furnace, and then the melting furnace keeping a temperature by adding 1 to 2 wt % of the ferro tungsten, 4 to 5 wt % of the ferro molybdenum, and 0.5 to 1 wt % of the ferro cobalt based on the weight of the pretreated wastes of the HSS processing process,
wherein the pre-treating wastes of the HSS processing process including 2 to 10 wt % of W, 1 to 5 wt % of Cr, 0.5 to 2 wt % of V, 1 to 10 wt % of Mo, and 1 to 10 wt % of Co,
a secondary melting step further comprising a secondary melt by secondarily melting of at least one of the ferro molybdenum, the ferro tungsten, the ferro cobalt, the ferro chromium, and the ferro vanadium, and the ingot-cast melt at 1000 to 1300° C., and
the recycling method is made to selectively manufacture the HSS master alloy containing compositions of any one or more of Mo, W, Co, Cr, and V.