Method of recycling by-product generated in papermaking process

Patent metadata

Field	Value
Publication number	US-10774471-B2
Application number	US-201815902093-A
Country	US
Kind code	B2
Filing date	Feb 22, 2018
Priority date	Jan 31, 2018
Publication date	Sep 15, 2020
Grant date	Sep 15, 2020

Abstract

A method of recycling a by-product generated in a papermaking process including, pulverizing a by-product produced in a papermaking process to prepare a pulverized product, burning the pulverized product to prepare a burned product, hydrating the burned product to prepare a hydrate; and manufacturing paper from the hydrate and a paper slurry is provided, which allows reuse of by-products generated in conventional papermaking processes such as lime mud and lime kiln CaO, which is environmentally friendly as well as cost-effective, and also the level of whiteness of the by-products such as lime mud and lime kiln CaO generated in a papermaking process can be improved to that of a high-grade raw material, making it possible to also improve the whiteness of paper.

First claim

What is claimed is:

1. A method of recycling a by-product generated in a papermaking process comprising:
pulverizing a by-product produced in a papermaking process to prepare a pulverized product;
burning the pulverized product to prepare a burned product;
hydrating the burned product to prepare a hydrate; and
manufacturing paper from the hydrate and a paper slurry;
wherein the by-product generated in the papermaking process comprises at least one of lime mud, lime kiln CaO, and
the by-product is obtained through an in-situ method for synthesizing precipitated calcium carbonate (PCC) filler in a pulp slurry.

2. The method of claim 1 , wherein,
burning the pulverized product is performed at a temperature of 900 to 1,300° C. for 0.5 to 3 hours.

3. The method of claim 1 , wherein,
hydrating the burned product is performed at a temperature of 20 to 90° C. for 3 to 12 hours after adding water.

4. The method of claim 1 , wherein the hydrate is Ca(OH) 2 .

5. The method of claim 1 , wherein manufacturing the paper comprises,
adding the paper slurry into a reaction tank,
adding the hydrate into the reaction tank and mixing to form a mixture,
injecting CO 2 gas into the mixture, and
adding the CO 2 gas-injected mixture to a sheet former for molding into paper.

6. The method of claim 5 , wherein the CO 2 gas is injected into the mixture at an injection rate of 50 cc/min.

7. The method of claim 5 , wherein the paper slurry is deinked pulp slurry.

Assignees

• Korea Inst Geoscience & Mineral Resources
• Korea Inst Of Geoscience And Mineral Resource

Inventors

• Ahn Ji-Whan

Classifications

• D21C11/0064

  Aspects concerning the production and the treatment of green and white liquors, e.g. causticizing green liquor · CPC title

• Y02P40/40

  Production or processing of lime, e.g. limestone regeneration of lime in pulp and sugar mills · CPC title

• D21C11/0007 Primary

  Recovery of by-products, i.e. compounds other than those necessary for pulping, for multiple uses or not otherwise provided for (volatile compounds obtained by decomposition of spent liquors in order to regenerate them D21C11/125; compounds obtained by fractionating the liquors in order to regenerate them D21C11/0042) · CPC title

• D21H17/63

  Inorganic compounds · CPC title

• D21H11/14 Primary

  Secondary fibres (working-up waste paper D21C5/02) · CPC title