US-12617697-B2 - Method and device for separation and recovery of heavy metal ions by membrane-forming mineralization fixation

Abstract

The present invention provides a method, and device for the separation and recovery of heavy metal ions by membrane-forming mineralization fixation, which belongs to the field of acid wastewater treatment technology containing heavy metal ions, comprises the following steps: mixing the composite mineral particles with the heavy metal acidic wastewater, performing a first hydration reaction under a standing condition, and performing adsorption-precipitation-crystallization on the heavy metal ions in the heavy metal acidic wastewater by the obtained colloidal liquid membrane to obtain particles with an outer layer having a mineralized membrane; the particles having a mineralized membrane in the outer layer have a spacing between the mineralized membrane and the particles; separating the particles having a mineralized membrane in the outer layer, and then respectively recovering the same; the process for the preparation method of the composite mineral particles comprises the following steps: mixing sodium carbonate/sodium silicate, bentonite, carbide slag and water, performing a second hydration reaction, and then successively performing granulation, aging, and dehydration condensation to obtain composite mineral particles; the particle size of the bentonite and carbide slag are independently ≤74 μm. The present invention can realize the separation and recovery of heavy metal ions by membrane-forming mineralization fixation and waste control by waste.

Inventors

• Liping Xiao
• Jichi BAI
• Yunlong LAN
• Yue Li
• Qiaoping KONG
• Baohua SHEN
• Dongxue Wang
• Zhihui DENG

Assignees

• Qingdao university of technology
• Qingdao OE Tiancheng Environmental Engineering Co., Ltd.

Dates

Publication Date

20260505

Application Date

20231128

Priority Date

20230717

Claims (9)

1. 1 . A film mineralization fixed separation and recovery method for heavy metal ions, including the following steps: mixing composite mineral particles with heavy metal acidic wastewater, and carrying out a first hydration reaction under static conditions to form a negatively charged colloidal liquid film rich in Ca(OH) 2 , using the colloidal liquid film to adsorb, precipitate and crystallize heavy metal ions in the heavy metal acidic wastewater to obtain particles with an outer mineralized film, the particles with the outer mineralized film have a spacing between the mineralized film- and the particles; separating the particles with an outer mineralized film to obtain a mineralized film and particles, and then recovering the film and particles separately; and a preparation method of composite mineral particles includes the following steps: mixing at least one of sodium carbonate/sodium silicate with bentonite, carbide slag and water, and carrying out a second hydration reaction, obtaining the composite mineral particles after granulation, aging and dehydration condensation; particle sizes of bentonite and carbide slag are independently ≤74 μm; bentonite and carbide slag are dried before use; drying the bentonite and the carbide slag at 100-110° C. for 2-4 h; wherein mixing at least one of the sodium carbonate/sodium silicate with the bentonite, carbide slag and water comprises first, mixing the sodium carbonate/sodium silicate, bentonite and carbide slag evenly obtain a mixture, followed by adding water to the mixture with mixing; the particle size of the product obtained by granulation is 2-7 mm.
2. 2 . The method according to claim 1 , wherein a dosage ratio of the composite mineral particles to the heavy metal acidic wastewater is 0.1-2.5 g:1 L.
3. 3 . The method according to claim 1 , wherein a mass ratio of bentonite to carbide slag is (15.5-57.5):(40-80); a mass of sodium carbonate/sodium silicate accounts for 2.5-4.5 wt % of a total mass of sodium carbonate/sodium silicate, bentonite and carbide slag.
4. 4 . The method according to claim 1 , wherein a chemical composition of the bentonite includes: SiO 2 :65-80%, Al 2 O 3 :11-17%, Na 2 O:0-6.0%, CaO:2.0-3.5%, MgO:2.0-5.0%, Fe 2 O 3 :1.6-4.0%, TiO 2 :0.04-0.20%, K 2 O:0.1-1.2% and other impurities: 0.10-2.16%; a chemical composition of the carbide slag includes CaO: 86.7-94.5%, SiO 2 :2.0-6.5%, Al 2 O 3 :0.5-3.0%, Na 2 O:0.5-2.5%, Fe 2 O 3 :0.2-1.5%, MgO:0.10-0.22%, TiO 2 :0.01-0.08% and other impurities: 1.0-1.72%.
5. 5 . The method according to claim 1 , wherein a total mass ratio of the sodium carbonate/sodium silicate, bentonite and carbide slag to water is 1:(0.5-0.9).
6. 6 . The method according to claim 1 , wherein an aging temperature is 10-35° C. and an aging time is 2-12 h.
7. 7 . The method according to claim 1 , wherein the dehydration condensation comprises drying for 24-48 h under natural conditions; or a temperature of the dehydration condensation is 150-450° C., and a time of the dehydration condensation is 0.6-1.5 h.
8. 8 . The method according to claim 1 , wherein the mineralized film is recovered as a raw material or finished product, and the particles are recovered as adsorbents.
9. 9 . The method according claim 1 , wherein the separating comprises a film mineralization fixed separation and recovery device for heavy metal ions, including lower layer plates and upper layer plates arranged in sequence; the upper layer plates are provided with through holes.

Description

This application claims priority to Chinese Patent Application No. 202310878015.7, filed on Jul. 17, 2023, and entitled ‘Method and Device for Separation And Recovery Of Heavy Metal Ions By Membrane-Forming Mineralization Fixation’ the entire disclosure of which is hereby incorporated by reference. TECHNICAL FIELD The present invention relates to the field of acid wastewater treatment technology containing heavy metal ions, in particular to a method, and device for the separation and recovery of heavy metal ions by membrane-forming mineralization fixation. BACKGROUND ART With the rapid development of industry, the large-scale exploitation of mineral resources has led to increasingly prominent environmental pollution problems, where, metal sulfide mines produce a large amount of acidic wastewater containing heavy metal ions in the process of mining, dressing, and smelting, as well as the discharged open-air stacked waste ore and tailings dam, these heavy metal acidic wastewater has the characteristics of a large amount of water, strong acidity (pH is 2-5), high concentration of heavy metal ions (ion content in per liter of water is from dozens to hundreds of milligrams), complex composition (containing a variety of heavy metals, such as iron, manganese, zinc, copper, plumbum, cadmium, chromium, etc.), strong toxicity, wide pollution range, long duration, and serious harm, in particular to the discharge of valuable heavy metal wastewater will also cause waste of mineral resources. Acidic wastewater containing heavy metals is discharged without timely and proper collection and treatment, which will eventually lead to heavy metal pollution of surface water, soil, crops, and groundwater, once it causes non-point source pollution, which is hard to treat, the effective treatment of heavy metal acidic wastewater is urgent and imminent. At present, the main treatment methods of heavy metal acidic wastewater comprise neutralization, chemical precipitation, electrolytic deposition, extraction, ion exchange, membrane separation, adsorption, wetland, and microbial methods, but there are still some problems, such as low treatment efficiency, a large amount of precipitated mud (hazardous waste), difficult separation of mud and water, small capacity of adsorbent, high cost, no energy saving, complex operation and difficult recovery of heavy metal ions, in particular, the valuable metals in wastewater are valuable mineral resources and have not been effectively mineralized, fixed and recycled. Therefore, how to treat heavy metal acidic wastewater and realize the resource utilization of industrial solid waste carbide slag, changing waste into valuables, waste control by waste, simultaneous treatment of wastewater and waste slag, mineralization fixation recovery of valuable metal resources in wastewater and circular economy have become urgent technical problems to be solved in this field. SUMMARY An objective of the present invention is to provide a method and device for the separation and recovery of heavy metal ions by membrane-forming mineralization fixation. The method for the separation and recovery of heavy metal ions by membrane-forming mineralization fixation can realize the purification treatment of recovery of heavy metal ions and heavy metal acidic wastewater by membrane-forming mineralization fixation and can realize the resource utilization of industrial solid waste carbide slag, changing waste into valuables, waste control by waste, simultaneous treatment of wastewater and waste slag, mineralization fixation recovery of valuable metal resources in wastewater and circular economy. In order to achieve the above objective, the present invention provides the following technical scheme: the present invention provides a method for the separation and recovery of heavy metal ions by membrane-forming mineralization fixation, comprising the following stepsmixing the composite mineral particles with the heavy metal acidic wastewater, performing a first hydration reaction under a standing condition, and performing adsorption-precipitation-crystallization on the heavy metal ions in the heavy metal acidic wastewater by the obtained colloidal liquid membrane to obtain particles with an outer layer having a mineralized membrane; the particles having a mineralized membrane in the outer layer have a spacing between the mineralized membrane and the particles;separating the particles having a mineralized membrane in the outer layer to obtain a mineralized membrane and particles, and then respectively recovering the same;the process for the preparation method of the composite mineral particles comprises the following steps:mixing sodium carbonate/sodium silicate, bentonite, carbide slag, and water, performing a second hydration reaction, and then successively performing granulation, aging, and dehydration condensation to obtain composite mineral particles;the particle size of the bentonite and carbide slag are independently ≤74 μm.