CN116216896A

CN116216896A - Purification method of sea sand alkali scrubbing wastewater

Info

Publication number: CN116216896A
Application number: CN202310332922.1A
Authority: CN
Inventors: 彭寿; 张乾伟; 陈勇; 石倩倩; 吴建新; 赵威; 刘中伟
Original assignee: China Building Materials Glass New Materials Research Institute Group Co Ltd
Current assignee: China Building Materials Glass New Materials Research Institute Group Co Ltd
Priority date: 2023-03-31
Filing date: 2023-03-31
Publication date: 2023-06-06

Abstract

The invention relates to a purification method of sea sand alkali scrubbing wastewater, which is characterized by comprising the following steps of: (1) Mixing alkylamine with acid to prepare alkylamine salt solution with pH value not higher than 7; (2) Preparing polyacrylamide into an aqueous solution with the mass concentration not higher than 1%; (3) Adding an trapping agent alkylamine salt solution into alkali scrubbing wastewater generated by sea-phase deposition type quartz sand ore dressing, and stirring and flocculating to obtain a micro-coagulation suspension; (4) And adding a polyacrylamide solution into the micro-coagulation suspension, stirring and standing to obtain a flocculating constituent and a transparent water phase. The invention has the advantages that: the alkylamine salt solution is used as a trapping agent, and the polyacrylamide is used as a flocculating agent, so that alkali scrubbing wastewater can be effectively treated, humus and clay particle solids in the wastewater can be efficiently and conveniently removed, the chromaticity of the wastewater is obviously reduced, and the treated wastewater can be returned to mechanical scrubbing operation for recycling.

Description

Purification method of sea sand alkali scrubbing wastewater

Technical Field

The invention belongs to the field of mineral processing, relates to the field of mineral processing of sea-phase deposition type quartz sand, and in particular relates to a purification method of sea sand alkali scrubbing wastewater.

Background

Sea-phase deposition type quartz sand deposits are one of important types of offshore quartz resources in China, and most of the quartz sand surfaces are adhered by cementing of ultrafine colloid organic humus and clay minerals in the deposition process; and a small part of the metal particles are embedded in the quartz cracks and pits. Mechanical scrubbing is an indispensable technological means for sea-phase sediment sand, and in order to further improve the mechanical scrubbing effect, dispersing agents such as sodium hydroxide, sodium hexametaphosphate, sodium carbonate and the like are added during scrubbing. Thus, the alkali scrubbing wastewater of the sea-phase sediment type quartz sand is a mixed suspension comprising organic humus, clay mineral, dispersant and water.

In actual production, the part of scrubbing wastewater is mainly in yellow brown, brown and red brown to black due to the difference of components and concentration. Because of the existence of the dispersing agent, the part of scrubbing wastewater has large medicament consumption and difficult sedimentation when adding conventional polyaluminium chloride (PAC), (anionic, cationic and nonionic) Polyacrylamide (PAM), and also causes unsmooth concentration and filtration, turbid filtrate and extremely difficult cyclic reuse in production.

At present, the treatment method of the industrial wastewater containing humus and fine-grained minerals mainly comprises the following steps:

a method for removing humus from an alkaline aqueous solution (application publication number CN107922224 a): adding a high cationic starch to aqueous alkaline waste water (containing humus such as dissolved lignin) from chemical pulp bleaching to precipitate humus, the high cationic starch having a charge density value of at least 1.8meq/g starch derivative dry matter measured at a pH of 7 to 7.5 and a viscosity of greater than 20mPas measured in a 3% starch aqueous solution with 5 times the amount of NaCl added; realizing the separation of the precipitated humus from the wastewater.

Industrial heavy metal sewage treatment method based on flocculation flotation precipitation (application publication number CN109626647 a): the method comprises the steps of taking healthy plants of water hyacinth as raw materials, modifying modified shell powder and chitosan, combining with polyaluminium ferric chloride, and finally mixing with a nano zinc oxide/carbon quantum dot complexing agent to prepare a final flocculant, wherein the flocculant comprises O ₃ The method comprises the steps of gas aeration, pH value adjustment, flocculation, air floatation, precipitation filtration and treatment of heavy metal ions in sewage.

A method for treating phosphorite flotation wastewater (application publication number is CN 110981015A): the wastewater in the regulating tank passes through a disc filter, and the effluent of the disc filter further enters a flocculant-added dissolved air flotation system to enable the flocculated wastewater to be dissolved and air-floated; and the filtered water almost does not contain solid suspended matters through a nanofiltration separation system, and can be used for household or agricultural irrigation.

In the method, the first scheme utilizes high-cation starch to adsorb humus with negative charges through electrostatic action, but the introduced cation starch is insoluble in water at normal temperature, and residual water quality is possibly turbid, so that the method is not suitable for mineral separation production practice. The second scheme uses the healthy water hyacinth plants, modified shell powder, chitosan, polyaluminium ferric chloride and nano zinc oxide/carbon quantum dot complexing agent, and then O ₃ The gas aeration, flocculation, air floatation and other processes have the advantages of various raw materials, higher cost and complex process conditions, and are difficult to adapt to the actual mineral separation production. The third scheme is to treat the phosphorite flotation wastewater containing the superfine suspended matters from the perspective of a nanofiltration and air floatation process method, and has no obvious reference significance to the sea sand beneficiation wastewater containing high-concentration humus.

Disclosure of Invention

The invention aims to solve the problem of high difficulty in treating mineral separation wastewater containing ultrafine high-concentration organic humus and clay mineral particles in the prior art, and provides a method for purifying sea sand alkali scrubbing wastewater.

In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:

the sea sand alkali scrubbing wastewater purification method is characterized by comprising the following steps:

(1) Preparing alkylamine salt solution: mixing alkylamine with acid to prepare alkylamine salt solution with pH value not higher than 7;

(2) Preparing a polyacrylamide solution: preparing polyacrylamide into an aqueous solution with the mass concentration not higher than 1%;

(3) Adding an trapping agent alkylamine salt solution into alkali scrubbing wastewater generated by sea-phase deposition type quartz sand ore dressing, and controlling the weight ratio of alkylamine to solid suspended matters to be 1:5-15% of 3-30%, stirring and flocculating to obtain micro-coagulation suspension;

(4) Adding polyacrylamide solution into the micro-coagulation suspension, controlling the weight ratio of polyacrylamide to solid suspension to be 1:0.5-3% and 12-60, stirring, and standing to obtain flocculation and transparent water phase.

Further, the alkylamine is an alkyl primary amine.

Further, the primary alkyl amine is dodecylamine or cocoamine.

Further, the acid is an organic carboxylic acid.

Further, the organic carboxylic acids include, but are not limited to, formic acid, acetic acid, oxalic acid, citric acid, and the like; the organic carboxylic acid has the advantages that the alkylamine salt solution prepared by the organic acid is transparent, and the alkylamine salt solution prepared by the inorganic acid (such as hydrochloric acid) is not semitransparent to milky white, so that the excessive turbidity of the filtrate caused by medicament residue can be prevented.

Further, the polyacrylamide is an anionic polyacrylamide, a cationic polyacrylamide or a nonionic polyacrylamide, and preferably an anionic polyacrylamide or a nonionic polyacrylamide.

Further, the alkali scrubbing wastewater is a uniform alkali scrubbing wastewater suspension containing humus sea sand with pH value not lower than 7 and without obvious sedimentation coarse particles.

Further, the flocculation group and the transparent water phase are filtered or press-filtered to obtain transparent clear filtrate and solid or filter cake containing humus and clay particles; the transparent clear filtrate is reused in mechanical scrubbing operation.

According to the invention, the alkylamine salt trapping agent is slowly added into the alkali scrubbing wastewater suspension, and stirring is carried out while the suspension is stirred until the chroma of the suspension is slightly shallow, so that the particle size of the suspension is increased, and the suspension has micro-coagulation signs, namely, the trapping effect is achieved, and the addition of the alkylamine salt trapping agent is stopped, so that the micro-coagulation suspension is obtained; slowly adding the prepared polyacrylamide flocculant solution into the micro-coagulation suspension, stirring while adding until obvious bridging humus flocculation particles appear in the suspension, slowly dripping the polyacrylamide flocculant until the volume of the aggregate flocculant is increased to a proper size, and stopping dripping the polyacrylamide flocculant; stirring for a certain time (1-5 min), and standing to obtain a two-phase system for realizing the flocculation of the humus-containing clay mineral particles and the transparent water phase.

According to the operation and the filtering process, the size of the floccules of the mineral particles containing humus and clay can be regulated, and the mineral particles float, suspend and sink (by increasing the addition amount of the alkylamine salt trapping agent and the polyacrylamide, the size of the floccules of the mineral particles containing humus and clay can be regulated, and the density of the floccules of the mineral particles containing humus and clay can be regulated; according to the requirements of different production multiplexing water quality, the chromaticity of the transparent water phase can be regulated and controlled to be from dark brown to light yellow to colorless.

The beneficial effects of the invention are as follows: compared with the use effects of the traditional polyaluminium chloride, the polyaluminium ferric chloride and the polyacrylamide, the invention uses the alkylamine salt solution as the trapping agent and the polyacrylamide as the flocculating agent, so that the alkali scrubbing wastewater can be effectively treated, humic substances and clay particle solids in the wastewater can be efficiently and conveniently removed, and the chromaticity of the wastewater is obviously reduced; the invention has simple treatment process, does not need aeration, air floatation and other treatments, and the treated wastewater can be returned to mechanical scrubbing operation for recycling.

Drawings

FIG. 1 is a diagram of an alkaline scrubbing wastewater according to the present invention;

FIG. 2 is a diagram of the wastewater after adding a collector to the alkaline scrubbing wastewater;

FIG. 3 is a diagram of the wastewater after adding a flocculant to the alkaline scouring wastewater;

FIG. 4 is a diagram of the filtrate and solids obtained after filtration through the filter cloth of example 1;

FIG. 5 is a diagram of the filtrate and solids obtained after filtration through the filter cloth of example 3.

Description of the embodiments

The sea sand alkali scrubbing waste water purifying process includes the following steps:

the sea sand alkali scrubbing wastewater in the following examples contained humus, and the wastewater was opaque and dark brown (see fig. 1), had a pH of about 9, and had a solids content of about 0.73% as measured by drying at 105 ℃;

example 1

(1) Preparing dodecylamine and acetic acid into a dodecylamine acetate aqueous solution with the mass concentration of 2% according to the weight ratio of 1:2 for later use;

(2) Dissolving anionic polyacrylic acid in water to prepare an aqueous solution with the mass concentration of 2 per mill for later use;

(3) Adding 10mL of a dodecylamine acetate aqueous solution into 200mL of a humus-containing sea sand alkali scrubbing wastewater suspension, stirring while adding until the suspension becomes light dark brown, suspended particles are enlarged and have coagulation signs, and stopping adding an alkylamine salt trapping agent to obtain a micro-coagulation suspension;

(4) Slowly adding 15mL of prepared polyacrylamide solution into the micro-coagulation suspension, stirring while adding, wherein obvious bridging humus flocculation particles appear in the suspension, stopping dripping the polyacrylamide flocculant, stirring for 2min, and standing for 10min to obtain a solid-liquid two-phase system (see the precipitated humus, clay particle flocculation and light yellow transparent water phase); the solid-liquid two-phase system was filtered through a filter cloth having a pore size of 15. Mu.m, whereby 1.40g of a solid of humus and clay particles as a floc and 190mL of a pale yellow transparent filtrate were obtained (see FIG. 4).

Example 2

The same procedure as in example 1 was employed, except that step (4) was conducted as follows:

slowly adding 15mL of prepared polyacrylamide solution into the micro-coagulation suspension, stirring while adding, and continuously dripping 5mL of polyacrylamide solution to increase the volume of the agglomerated floccules until the size of the floccules is more than 1mm, and stopping dripping the polyacrylamide flocculant; stirring for 2min, and standing for 10min to obtain a solid-liquid two-phase system (see the precipitated humus-containing, clay particle floccules and yellowish transparent water phase); the solid-liquid two-phase system is filtered by filter cloth with the aperture of 15 mu m, thus obtaining 1.42g30g of humus and clay particle flocculus solid and 225mL of light yellow transparent filtrate.

Example 3

8mL of a dodecylamine acetate aqueous solution is continuously added into the micro-coagulation suspension, stirring is carried out while adding until suspended particles are obviously enlarged and coagulated, 15mL of a prepared polyacrylamide solution is slowly added, stirring is carried out while adding, and bridging humus flocculation particles appear in the suspension; stirring for 2min, and standing for 10min to obtain a solid-liquid two-phase system (see below, suspended humus-containing, clay particle floc and almost colorless transparent water phase); the solid-liquid two-phase system was filtered through a filter cloth having a pore size of 15. Mu.m, whereby 1.37g of a solid of humus and clay particles and 220mL of a colorless transparent filtrate were obtained (see FIG. 5).

Example 4

continuously adding 8mL of a dodecanol acetate aqueous solution into the micro-coagulation suspension, stirring while adding until suspended particles are obviously increased and coagulated, slowly adding 15mL of a prepared polyacrylamide solution, stirring while adding, and continuously dripping 8mL of a polyacrylamide solution until the volume of the agglomerated floccules is increased to more than 2mm, and stopping dripping the polyacrylamide flocculant; stirring for 2min, and standing for 10min to obtain a solid-liquid two-phase system (see below, suspended humus-containing, clay particle floc and almost colorless transparent water phase); the solid-liquid two-phase system is filtered by filter cloth with the aperture of 15 mu m, thus obtaining 1.40g of humus and clay particle flocculus solid and 235mL of colorless transparent filtrate.

In the above examples, the addition amounts of the laurylamine trapping agent and the polyacrylamide flocculant are all the initial addition amounts, and the cyclic accumulation is not considered, so that the addition amounts of the corresponding reagents after the cyclic accumulation are reduced.

The above embodiments are merely illustrative of the preferred embodiments of the present invention and are not intended to limit the scope of the invention, which is defined in the claims and all changes that fall within the principles of the invention.

Claims

1. The sea sand alkali scrubbing wastewater purification method is characterized by comprising the following steps:

(3) Adding an trapping agent alkylamine salt solution into alkali scrubbing wastewater generated by sea-phase deposition type quartz sand ore dressing, and controlling the weight ratio of alkylamine to solid suspended matters to be 1:3-305-15%, stirring and flocculating to obtain micro-coagulation suspension;

(4) Adding a polyacrylamide solution into the micro-coagulation suspension, and controlling the weight ratio of the polyacrylamide to the solid suspension to be 1: and (3) stirring and standing 0.5-3% of the mixture to obtain floccules and a transparent water phase.

2. The method for purifying sea sand alkali scrubbing wastewater according to claim 1, wherein the method comprises the following steps: the alkylamine is an alkyl primary amine.

3. A method for purifying sea sand alkali scrubbing wastewater according to claim 2, wherein: the alkylamine is dodecylamine or cocoamine.

4. The method for purifying sea sand alkali scrubbing wastewater according to claim 1, wherein the method comprises the following steps: the acid is an organic carboxylic acid.

5. The method for purifying sea sand alkali scrubbing wastewater according to claim 4, wherein: the organic carboxylic acid is formic acid, acetic acid, oxalic acid or citric acid.

6. The method for purifying sea sand alkali scrubbing wastewater according to claim 1, wherein the method comprises the following steps: the polyacrylamide is anionic polyacrylamide, cationic polyacrylamide or nonionic polyacrylamide.

7. The method for purifying sea sand alkali scrubbing wastewater according to claim 1, wherein the method comprises the following steps: the alkali scrubbing wastewater is a humus-containing sea sand alkali scrubbing wastewater suspension which is uniform, has no obvious sedimentation coarse particles and has a pH value of not lower than 7.

8. The method for purifying sea sand alkali scrubbing wastewater according to claim 1, wherein the method comprises the following steps: and filtering or press-filtering the flocculation mass and the transparent water phase to obtain transparent clear filtrate and solid or filter cake containing humus and clay particles, wherein the transparent clear filtrate is reused in mechanical scrubbing operation.