JPS58177194A - Treating agent formed by synthesizing and granulating powdery body of coralline fossil for adsorbing and removing heavy metal from waste water - Google Patents

Abstract

PURPOSE:To efficiently adsorb and remove heavy metals from waste water, by adding an adsorbing-removing agent obtd. by adding the specified amount of Portland cement to the fine powdery body of coralline fossils having different main components, granulating the mixture and baking it to the waste water containing heavy metals. CONSTITUTION:The fossil of an existing coral reef, the fossil of an upheaval coral reef and the limestone of a coral reef are crushed and mixed into a powdery body of 200-300 meshes. This mixed powdery raw material of coralline fossils is mixed with Portland cement (clinker powder having the composition of silica, alumina, ferric oxide and calcium oxide) as a binder in an amount of 0.8-1.0wt% based on said powdery raw material. Thereafter, the mixture is blended while being damped, granulated with pressure by a briquetting granulator and then sintered at 400-500 deg.C to manufacture the agent for adsorbing and removing heavy metals from waste water. This adsorbing-removing agent is brought into contact with waste water containing heavy metals for 30-60min, to adsorb and remove the heavy metals.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention was previously proposed in Application No. 57-017466, but coral reef fossils with different compositions are made into fine powder, mixed to form a uniform raw material, and an appropriate amount of an effective granulation aid is added. The present invention relates to the granulation malleability of an adsorption treatment agent that selectively and efficiently adsorbs and removes heavy metals from heavy metal-containing wastewater solutions by synergistically combining adsorption capacity and ion exchange reactivity through synthesis.

Coral reef fossils vary depending on their form of existence or generation date.
It is broadly divided into living coral reef fossils, raised coral reef fossils, and coral reef limestones. In order to use these coral reef fossils as raw materials, it is necessary to make their main components and composition uniform.

The present invention uses Portland cement (silica, Clinker powder containing alumina, ferric oxide, and calcium 7 oxide)
Synthesize by adding 0.8 to 1.0% by weight of powder, mix uniformly, knead with water, pressure granulate with a briquerating granulator,
The product was sintered at UO°C to 500'C, preferably at 500°C, to obtain the desired adsorption and removal treatment agent for heavy metal wastewater as an invention product.

Conventionally, wastewater treatment for heavy metals has generally been carried out using oxidation, reduction, or biological treatment as a pretreatment, followed by neutralization with sulfide to remove most of the heavy metals, and then remove the remaining small amounts of heavy metals using ion exchange resin or other methods. Adsorption treatment is performed using activated carbon, but when considering the current and future total amount regulations, an efficient adsorption method seems to be optimal. What is actually required in industry is the treatment of wastewater with low concentrations of heavy metals, and what is desired is a highly efficient and economical treatment agent that can be used with simple, compact equipment or existing equipment that can be used as is without operational errors. . In addition, there is a need for a treatment agent that can reduce the generation of industrial waste from used treatment agents.

The processing agent of the invention was intended to meet and provide these requests.

To be more specific, existing coral reef fossils, raised coral reef fossils, and coral reef limestone are porous and have a composition mainly composed of calcium oxide, and calcium ions easily undergo ion exchange reactions with heavy metal ions. In addition, focusing on the adsorption properties based on micropores, existing coral reef fossils, raised coral reef fossils, and coral reef limestone were crushed and
It is fired and processed into grains of ~60 mesh, and cadmium,
In an experiment in which copper, zinc, mercury, and hexavalent chromium were adsorbed and removed, 209/l of a particle shape treatment agent was added to an aqueous solution of heavy metals with a concentration of 10~/l, stirred for 60 minutes, and analyzed using the specified analysis method. The treated water was measured.

The analysis results showed that adsorption and removal efficiency of about 90% was obtained for cadmium and copper, but the removal rate was low for zinc, mercury, and hexavalent chromium, and that the particle form due to crushing showed that it was difficult to remove existing coral reef fossils. Because there are slight differences in the composition of uplifted coral reef fossils and coral reef limestone (Table 1), it has been found that it is difficult to always achieve an average adsorption removal ability.In addition, in experimental treatments, sludge formation due to pressure abrasion of the treatment agent was found to be difficult. There was a possibility that there was a possibility that the processing equipment would be clogged (9), resulting in negative operational performance.

The treatment agent of the invention corrects and improves the drawbacks of this method, and we have considered granulating it as a powder as a method to safely and reliably increase the adsorption capacity and increase the removal efficiency.

To explain its composition, the advantages of granulating from powder are that compared to crushed granules, the specific surface area of the adsorption capacity is greatly expanded and the composition is uniform, which is an essential requirement for a processing agent. In addition to water resistance, pressure resistance, and abrasion resistance, it has high coagulability and strength, and can be made insoluble.

The coral reef fossil powder of the invention is porous and has the characteristics of adsorption, plasticity, and self-bonding properties that easily penetrate into microscopic pores. agent is necessary, and its selection is important.

Titanium oxide as a granulation aid, with the aid itself intervening in the bond;
There are wax emulsions and CMC (carboxymethyl cellulose) that contain silica to promote compaction and compaction, as well as coal tar pitch that fills the voids in powder and bonds between particles, and particles that cover raw material powder with a thin film. Water glass, pulp waste liquid, etc. are used as liquid auxiliary agents that bind materials and strengthen them by heating and drying after formation, but as a result of experiments, Portland cement contains silica, alumina, ferric oxide, and calcium oxide. cement clinker
Therefore, it was found that the composition of the coral reef fossil powder, which is the raw material for the invention, is the same, and that it is optimal for effectively bonding between powder particles and promoting ion exchange reactions, and the powder ratio is the same. Add and synthesize 0.8 to 1.0% by weight, mix uniformly, add water and knead, pressure granulate using a briquerating granulator, air dry for 48 hours, and then bake at 400°C to 500°C, preferably 500°C. The finished product was made into an insoluble treatment agent with high coagulability and strength.

Next, a method of implementing the present invention will be described.

Example (1) In the action of the granulation aid during the experimental granulation process, the CMC (carboxymethyl cellulose) t-powder ratio was 0.8 to 1.0.
When % by weight is added and mixed, granules are formed by kneading with water, pressure granulation, and calcination, but when immersed in water, they become soft in a short time and have no water resistance, making them unsuitable as adsorption treatment agents. When titanium is added and synthesized as a granulation aid, water-kneading,
Pressure granulation resulted in a granular shape, but it broke during the firing stage, making it impossible to obtain the desired product.

Next, regarding the mixing ratio of the granulation aid Portland cement of the invention, in addition synthetic granulation with a powder ratio of 1.5 to 2-0 weight, the adsorption capacity decreases, and the powder ratio is 0.3 to 0.5311.
With 1% additive synthetic granulation, sludge was generated in the adsorption treatment experiment, and there was a limit to wear resistance and there were concerns about strength.

Example (2) The powder of the invention was added at a ratio of 08 to 1.0% by weight, mixed uniformly, kneaded under pressure, and granulated under pressure using a briquerating granulator, preferably at 400°C to 500°C. The granulation treatment agent sintered at 500℃ does not require any of the oxidation, reduction, biological treatment, or sulfide neutralization pretreatment methods that are conventionally used to treat heavy metal wastewater. Experimental data table (
In the experiment of adsorption and removal treatment of heavy metal aqueous solution in 2) concentration, treatment time, and adsorption treatment water analysis of aqueous solution raw water,
In a treatment time of 30 to 60 minutes, we obtained adsorption and removal efficiency of 99.8% (undetectable) for copper, 98.57% for cadmium, 97.5% for zinc, and a slightly lower 86.3% for mercury. The adsorption removal rate decreased. Since hexavalent chromium exists in acidic and alkaline forms, pretreatment with sodium sulfite and subsequent treatment for 60 minutes showed an adsorption removal efficiency of 99.8% (undetectable).

Example (3) In addition, in a comparative experiment of adsorption removal rate with coconut shell activated carbon, Table (
As in 3), using the cadmium raw aqueous solution concentration of 538η/l, the invention treatment agent was 30? /l and stirring for 30 minutes, the concentration of the treated aqueous solution was 0.4■/1,1160 minutes, the concentration of the treated aqueous solution was 0.22■/1. The adsorption removal rate is 99 in 30 minutes.
2%, an efficiency of 99.5% was obtained in 60 minutes.

In the coconut shell activated carbon treatment, the same 30V was input, the treatment time was 30 minutes, the treated water concentration was Z30IIv/l, the 60 minute treatment was 1.30 ■/l, and the adsorption removal rate was 95 in 30 minutes.
7%, and 97.4% in 60 minutes, confirming that the inventive treatment agent has superior adsorption and removal ability to coconut shell activated carbon and is effective.

Example (4) In addition, a comparative experiment was conducted on the adsorption and removal efficiency of the following crushed granule treatment agent and the granulation treatment agent of the present invention.The analysis method was JISK-0102 atomic absorption spectrometry for cadmium, and the environmental This was carried out using Office Notification No. 64 atomic absorption spectrophotometry.

The adsorption removal rate of the invention granulating agent is 20 f/ (units ~/
l) Measurement items Raw water concentration Treatment time Treated water concentration Adsorption removal rate (a) Cadmium 10.60 60 minutes
0.065 99.5 Mercury 10.
95 60 minutes 0.21 99.0 Adsorption removal rate of crushed particles 20 t/ is used (unit ~/l)
Measurement item Raw water 11K Treatment time Treated water concentration Adsorption removal rate (a) Cadmium 10.60 60 minutes
2.00 81.0 Mercury 10.
95 60 minutes 7.40 30.0 Example (5) Next, as an experiment to determine whether or not the invention treatment agent was insoluble, the solubility of the treatment agent used was analyzed and measured. The solubility experiment used the one used in the adsorption treatment experiment of the invention granulating agent described above. Cadmium raw aqueous solution concentration 10611j? /11 Grain treatment agent 20
9/l was used, the treated water bath concentration was 0065 to 7 t, and the adsorption removal rate was 99.5%, so the measurement showed that the treatment agent used had a cadmium concentration of 1053/l, and was directly added to 1 t of fresh water. After 48 hours of immersion in water, the concentration of the aqueous solution was analyzed using JISK-0102 atomic absorption spectrophotometry, and cadmium could not be detected (the limit of quantification was 0.005 μ/cm).
is below. ) Mercury is an aqueous solution concentrated in raw water [10,95■/
1 was treated with the treatment agent 207 of the invention for 60 minutes, and the treated aqueous solution concentration was 021/1. Since it has an adsorption removal rate of 99%, it can be said that it is a treatment agent that has a mercury content of 1074 cm/day according to foot measurements.

As with cadmium, the concentration of the aqueous solution after immersing it in 1 ton of fresh water for 48 hours and then directly above the water was analyzed using atomic absorption spectrophotometry. The result was 0.0054/l, and the heavy metal solution was hardly eluted from the treatment agent, making it insoluble. It was confirmed that

Therefore, since the inventive treatment agent exists in a concentrated state of the adsorbed heavy metal solution, the adsorbed material is removed by the f6# operation and useful metals can be recovered, resulting in resource conservation.

In addition, even in the final disposal of used processing agents, they are insoluble, and heavy metals once adsorbed do not elute unless they come into contact with strong acids, so there is no risk of secondary pollution even if they are disposed of, and they become a citadel for industrial waste.1. Landfilling and reuse of cement aggregate, etc. are possible.

In related applications, it can be effectively applied to the treatment of wastewater containing different types of heavy metals or harmful substances, for example, aluminosilicate can be added to the powder raw material of the invention to create an adsorption treatment agent for radioactive wastewater. It is thought that it can be applied to granulation.

Claims (1)

[Claims] (1) Compositional properties of living coral fossils, raised coral reef fossils, and coral reef limestones that have different main components? To make it uniform, grind it into a fine powder of 200 to 300 mesh, mix it, and add Portland cement (white) as a granulation aid to a powder ratio of 0.8 to 300.
Synthesize by adding 1.0% by weight, mix uniformly, add water, knead, pressure granulate, sinter at 400°C to 500°C, preferably 500°C, and size into a cylindrical shape of 2 to 3 deafness. As a strong granulation treatment agent with high coagulability, it can be used as a heavy metal wastewater solution by omitting the pretreatment (oxidation method, reduction method, biological treatment method, and use of sulfide neutralizing agent) of conventional heavy metal wastewater treatment methods. 30 minutes to 6
A granulation method for a processing agent that efficiently adsorbs and removes heavy metals by contacting them for 0 minutes.
-(2. The effectively acting granulation aid Portland cement described in claim 1 is obtained by selecting clinker powder containing silica, alumina, ferric oxide, and calcium oxide as components, and By adding and synthesizing 0.8 to 1.oxt%, K powder adsorption ability promoted ion exchange reactivity in wood, and added a synergistic effect between adsorption ability and ion exchange reaction. (3) Claims No. By adding an appropriate amount of the effective granulation aid described in item 1, granulating it under pressure, and sintering it, the product becomes insoluble and its mechanical strength is increased.
Invented products can be reactivated and reused, and heavy metals once adsorbed will not elute unless they are brought into contact with strong acids, so there is no risk of secondary pollution even when they are disposed of, and the amount of industrial waste generated can be reduced. can.