Title:
METHOD FOR HAZARD-FREE TREATMENT OF SLUDGE FROM SPENT SOLUTION OF MIXED ACIDS AFTER ACID WASHING OF STAINLESS STEEL
Document Type and Number:
WIPO Patent Application WO/2021/017940
Kind Code:
A1
Abstract:
Disclosed is a method for hazard-free treatment of a sludge from a spent solution of mixed acids after acid washing of stainless steel, comprising the following steps: 1) feeding a spent acid washing solution to a precipitation unit and performing a precipitation treatment, whereby a sludge is formed at the bottom of the precipitation unit from the spent solution of mixed acids; 2) filtering the sludge from the spent solution of mixed acids and feeding the sludge to a sludge storage unit and performing blending, mixing, and homogenization; 3) spraying the homogenized sludge into a calcination furnace to allow chemical reactions to occur, generating solid metal oxides, HF gas, and HNO3 gas; and 4) discharging the solid metal oxides falling to the bottom of the calcination furnace by using a scraping rake, and allowing the HF gas and HNO3 gas to exit the top of the calcination furnace, pass through a preconcentrator, and enter an absorption tower to undergo acid regeneration. The present invention can reduce the production of acidic sludge and decrease the treatment cost borne by a metallurgical enterprise. Moreover, the present invention allows reclamation of acidic sludge having a high economic value by increasing the recovery rate of F- and NO3
-, recovering abundant amounts of high-value metal ions, such as nickel, chromium, titanium, and molybdenum in the acidic sludge, and forming solid metal oxides having a high added value.
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Inventors:
ZHAO JINBIAO (CN)
GUO JINCANG (CN)
GAO JUNFENG (CN)
DING YU (CN)
WANG JUN (CN)
GUO JINCANG (CN)
GAO JUNFENG (CN)
DING YU (CN)
WANG JUN (CN)
Application Number:
PCT/CN2020/103165
Publication Date:
February 04, 2021
Filing Date:
July 21, 2020
Export Citation:
Assignee:
WISDRI ENGINEERING & RES INCORPORATION LIMITED (CN)
International Classes:
C02F11/00; C01B7/19; C01B21/46; C02F101/20
Domestic Patent References:
| WO2014036575A1 | 2014-03-13 |
Foreign References:
| CN110330199A | 2019-10-15 | |||
| CN210528729U | 2020-05-15 | |||
| CN101343123A | 2009-01-14 | |||
| CN108506946A | 2018-09-07 | |||
| CN103319038A | 2013-09-25 | |||
| CN87103373A | 1988-11-23 |
Attorney, Agent or Firm:
BEIJING HUIZE INTELLECTUAL PROPERTY LAW LLC (CN)
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