Method for stabilization of reducing slag

Patent metadata

Field	Value
Publication number	US-2025305074-A1
Application number	US-202418678935-A
Country	US
Kind code	A1
Filing date	May 30, 2024
Priority date	Mar 28, 2024
Publication date	Oct 2, 2025
Grant date	—

Abstract

A method for stabilizing a reducing slag includes the steps of: subjecting a reducing slag which contains an alkaline earth metal oxide to a drying treatment, so as to obtain a dried reducing slag; mixing a urease-producing bacterium, a fermentation medium, and a nutrient, followed by conducting a fermentation treatment, so as to obtain a fermentation product containing urease; subjecting the fermentation product to a foam fractionation treatment, so as to obtain a foam containing urease; mixing the dried reducing slag, the foam containing urease, and urea, followed by conducting a urea hydrolysis reaction and a precipitation reaction in sequence, so as to obtain a product containing a stabilized reducing slag and a residual liquid; and subjecting the product to a solid-liquid separation treatment, so as to separate the stabilized reducing slag and the residual liquid from the product.

First claim

What is claimed is:

1 . A method for stabilizing a reducing slag, comprising the steps of:
(a) subjecting a reducing slag which contains an alkaline earth metal oxide to a drying treatment, so as to obtain a dried reducing slag, the alkaline earth metal oxide being selected from the group consisting of calcium oxide, magnesium oxide, and a combination thereof; (b) mixing a urease-producing bacterium, a fermentation medium, and a nutrient, followed by conducting a fermentation treatment, so as to obtain a fermentation product containing urease; (c) subjecting the fermentation product containing urease obtained in step (b) to a foam fractionation treatment, so as to obtain a foam containing urease, a concentration of the urease in the foam being greater than a concentration of the urease in the fermentation product; (d) mixing the dried reducing slag obtained in step (a), the foam containing urease obtained in step (c), and urea, followed by conducting a urea hydrolysis reaction and a precipitation reaction in sequence, so as to obtain a product containing a stabilized reducing slag and a residual liquid; and (e) subjecting the product obtained in step (d) to a solid-liquid separation treatment, so as to separate the stabilized reducing slag and the residual liquid from the product.

2 . The method as claimed in claim 1 , wherein in step (b), the urease-producing bacterium is an aerobic bacterium selected from the group consisting of Sporosarcina pasteurii, Bacillus subtilis , and a combination thereof.

3 . The method as claimed in claim 1 , wherein in step (b), the urease-producing bacterium is an anaerobic bacterium selected from the group consisting of Lactobacillus plantarum, Lactobacillus rhamnosus, Lactobacillus fermentum , and combinations thereof.

4 . The method as claimed in claim 1 , wherein in step (c), the foam fractionation treatment is conducted by introducing a gas into the fermentation product containing urease, so as to generate the foam containing urease.

5 . The method as claimed in claim 4 , wherein the gas is air.

6 . The method as claimed in claim 1 , wherein in step (a), the reducing slag is subjected to a sterilization treatment before or simultaneously with the drying treatment, the sterilization treatment being conducted using ultraviolet light.

7 . The method as claimed in claim 1 , wherein in step (a), the dried reducing slag is further subjected to a sterilization treatment after the drying treatment, the sterilization treatment being conducted using ultraviolet light.

8 . The method as claimed in claim 1 , wherein in step (a), the drying treatment is conducted using sunlight.

9 . The method as claimed in claim 1 , wherein in step (b), the fermentation treatment is conducted at a temperature ranging from 15° C. to 40° C. for a time period ranging from 16 hours to 120 hours.

10 . The method as claimed in claim 1 , wherein in step (c), the foam fractionation treatment is conducted at a temperature ranging from 15° C. to 40° C.

11 . The method as claimed in claim 1 , wherein in step (d), the urea hydrolysis reaction and the precipitation reaction are conducted at a temperature ranging from 15° C. to 40° C.

Assignees

• Univ Nat Chung Cheng

Inventors

• Chen Chien-Yen
• Huang Yi-Hsun
• Lin Pin-Yun
• Wang Chin-Wen

Classifications

• C21B2400/02

  Physical or chemical treatment of slags · CPC title

• C22B7/04

  Working-up slag · CPC title

• C21B3/06 Primary

  Treatment of liquid slag · CPC title