CN100415360C - A kind of method that uses ion adsorption type rare earth to prepare sewage dephosphorization adsorbent - Google Patents

Abstract

The invention relates to a method for preparing an adsorbent for dephosphorization of sewage by using ion-adsorbed rare earths. The ion-adsorbed rare earth ore and clay are prepared in a weight ratio of 10:0.5-4, granulated, and heated at a temperature of 500-800°C. Roasting for 1 to 3 hours, put into the reactor and activate with acid activation solution for 4 to 8 hours, then adjust the pH of the activation solution to 8 to 12 with lye, recirculate and activate for 4 to 8 hours, and then recirculate at a temperature of 100 to Dry at 120°C for half an hour, then raise the temperature at a rate of 10-20°C per minute, roast at a final temperature of 400-700°C for 0.5-2 hours, and cool to obtain an ion-adsorption type rare earth adsorbent. The adsorbent can be applied to the treatment of various wastewaters, especially the treatment of nitrogen and phosphorus pollution in water bodies, and the adsorption capacity can reach more than 15mg/g.

Description

A kind of method that uses ion adsorption type rare earth to prepare sewage dephosphorization adsorbent

1. Technical field:

The invention relates to an ion-adsorption type rare earth adsorbent for waste water treatment, belonging to the technical field of waste water treatment.

2. Background technology:

The eutrophication of closed water bodies has become a serious environmental problem, which affects and restricts the coordinated development of society. Nitrogen and phosphorus nutrients are the main substances that cause eutrophication of water bodies. With the increasing development and utilization of environmental resources by human beings, a large amount of domestic sewage and industrial wastewater containing nitrogen and phosphorus nutrients are discharged into rivers and lakes, which increases the load of eutrophic substances in water bodies. Nutritization, accelerate the aging of water body. The world-renowned limnologist Vollenweider believes that eutrophication is defined as total phosphorus exceeding 20 μg/L. Urban sewage is rich in nitrogen and phosphorus. After being treated by urban sewage treatment plants, the concentration of phosphorus is still above 1.0mg/L. However, the urban sewage discharge is increasing rapidly, with an annual increase of 2.4 billion m ³ (6.67 million m ³ / d). According to statistics, the major lakes in China are polluted by nitrogen and phosphorus, resulting in eutrophication, accounting for 56% of the lakes in statistics. Therefore, it has become one of the urgent tasks in the field of environmental protection to develop efficient, cheap and easily regenerated nitrogen and phosphorus removal adsorbents and related technologies.

At present, domestic and foreign wastewater phosphorus removal methods mainly include chemical coagulation precipitation method, ion exchange method, biochemical method and adsorption method. The chemical coagulation precipitation method has a stable treatment effect, a high phosphorus removal rate, and is easy to operate. However, it produces a large amount of sludge that is difficult to handle, and the increase in the concentration of salt in the effluent also limits its popularization and application; the biochemical method requires control and management. Higher, it is difficult to maintain efficient and stable phosphorus removal effect; ion exchange adsorption has attracted more and more attention due to its unique advantages of high efficiency and rapidity, simple operation, no secondary pollution, and reusable adsorbent. The commonly used adsorption materials at home and abroad mainly include activated carbon, activated alumina, silica gel, zeolite and synthetic zeolite. However, these adsorption materials have disadvantages such as poor stability, low adsorption capacity, and frequent regeneration.

In the publication number CN86108921A, a composite inorganic adsorbent and a preparation method thereof are disclosed. The method is as follows: "Firstly, the raw material clay ore and activated carbon are pulverized respectively to pass through a 200-mesh sieve, and then weigh a certain amount of Put the clay ore and activated carbon above 200 mesh in the mixer, stir slowly to make it fully mixed, then add a certain amount of binder in proportion, and continue to stir until the material in the mixer forms a uniform paste, Transfer the paste to an extrusion molding machine, extrude it into strips of Φ(2.5～4)×(4～6)mm, air-dry it under natural conditions for 0.5～1 day, and then move it into the drying room , dried at 100-110°C for 2-4 hours, then transferred into a roasting furnace, roasted at 550-650°C for 1-4 hours, slowly cooled and taken out to obtain the composite inorganic adsorbent described in this invention ".

In the publication number CN1184001A, the production process of bentonite adsorbent is disclosed. The speed is 90-120r/min, and the stirring time is 2-4 hours; then, add sulfuric acid for acidification, the amount of acid added is 10-40%wt, the reaction temperature is 80-100°C, and the holding time is 4-6 hours; then, wash with water until the pH = 3~5. After press filtration, the filter material is controlled to have a moisture content of 30~55%wt, and is directly extruded, or extruded with borax or silica sol additives; 0.5 to 4 hours; finally, it is crushed, sieved, packaged or washed with water after sieving, dried at a temperature of 110-280°C, and packaged.”

The publication number is CN85102706A, which discloses carbon _{dioxide laser} gas impurity regeneration platinum-rare earth catalyst and its preparation method. Minutes, washed once with water, after the treated Al ₂ O ₃ is dried and roasted at 500-600°C for 2 hours, firstly impregnated with rare earth metal ions (mixed rare earth chloride or cerous nitrate solution), then dried, at 700-600°C Calcination at 900°C for 3 hours. Second impregnation of Pt metal ions (H ₃ PtCl ₆ ), followed by drying at 110°C and calcination at 550°C. Reduction treatment with H ₂ gas at 350-400°C for 2 hours."

my country is rich in rare earth mineral resources and has superior ore-forming conditions, which can be called unique advantages. The proven reserves rank first in the world, providing a solid foundation for the development of my country's rare earth industry. The present invention utilizes my country's abundant ion-adsorption type rare earth ores (heavy rare earth element content 0.06wt% ~ 5wt%, light rare earth element content 0.1wt% ~ 3wt%) after appropriate processing to produce a high adsorption capacity, production and An ion-absorbing type rare earth adsorbent with low operating cost and wide application range. The adsorbent overcomes the shortcomings of the existing wastewater phosphorus removal technology, can greatly remove the phosphorus pollutant content in sewage, and deeply remove phosphorus from sewage flowing into lakes and rivers, so that the phosphorus concentration can reach GB3838-2002 "Surface Water Environment "Quality Standard" III water quality standard, reduce or eliminate the nutrient load of lakes and rivers from the source, so as to alleviate the eutrophication of lakes and rivers. In addition, the ion adsorption type rare earth adsorbent of the present invention can also be used for the treatment of chromium-containing wastewater, fluorine-containing wastewater, arsenic-containing wastewater, and domestic sewage for deep nitrogen and phosphorus removal.

3. Contents of the invention:

The purpose of the present invention is to provide a preparation method of an ion-adsorption type rare earth adsorbent. After the ion-adsorption type rare earth ore and clay are prepared, granulated, roasted, activated, dried and roasted, the ion-adsorption type rare earth adsorbent is obtained. The adsorbent can be applied to the treatment of various wastewaters, especially the treatment of nitrogen and phosphorus pollution in water bodies, and the adsorption capacity can reach more than 15mg/g.

The present invention is accomplished by the following steps

(1) Raw material preparation: prepare the ion-adsorbed rare earth ore and clay at a weight ratio of 10:0.5-4, and mix them evenly to form a mixture. In the ion-adsorption type rare earth ore, the content of heavy rare earth elements can be 0.06-5wt%, and the content of light rare earth elements can be 0.1-3wt%;

(2) Granulation: add 10-40% water of its weight to the mixture for granulation;

(3) Roasting: the mixture after granulation is put into a roasting furnace for roasting treatment, the roasting temperature is 500-800°C, and the roasting time is 1-3 hours;

(4) Activation: The mixture after roasting is put into the reactor, and sulfuric acid or hydrochloric acid with a concentration of 0.2-2mol/L is used as the activation solution. The activation liquid carries out circulation activation treatment to the mixture, the weight ratio of the mixture and the activation liquid is 1:20-50, the activation time is 4-8 hours at normal temperature, then the pH value of the activation liquid is adjusted to 8-12 with lye, and then Carry out circulation activation treatment at the same line speed as above for 4 to 8 hours;

(5) Drying and roasting: The activated mixture is put into the roasting furnace for drying treatment. The drying temperature is 100-120°C, dried for half an hour, and then heated at a rate of 10-20°C per minute. The final roasting temperature is 400～700℃, roasting time 0.5～2 hours, after cooling, the ion adsorption type rare earth adsorbent is obtained.

Main advantage of the present invention has:

(1) Abundant ion-adsorption type rare earth ore (heavy rare earth element content 0.06wt% ~ 5wt%, light rare earth element content 0.1wt% ~ 3wt%) is made into an adsorbent with an adsorption capacity of more than 15mg/g, and the production cost is low .

(2) The ion adsorption type rare earth adsorbent can be applied to the treatment of various water pollutants, especially the treatment of nitrogen and phosphorus pollution in water.

(3) The saturated ion adsorption type rare earth adsorbent can be regenerated after being immersed in an alkaline regeneration solution containing NaCl, so that the adsorbent can be recycled.

(4. Description of drawings

Fig. 1 is a flow chart of the preparation process of the ion-adsorption type rare earth adsorbent of the present invention.

5. Specific implementation methods:

Example 1:

The heavy rare earth element content is 5wt%, the light rare earth element content is 0.1wt% the ion adsorption type rare earth ore and the clay are prepared according to the weight ratio of 10:2, mix uniformly to be a mixture; and add this mixture weight 20% The water is granulated to obtain a cylindrical mixture with a diameter of 2.5mm to 10mm and a height of 3mm to 20mm; then the cylindrical mixture is put into a vertical tubular roaster for roasting treatment, and the roasting temperature is 600°C , roasted for 2 hours; the mixed material after roasting was put into the fixed bed reactor again, and the linear velocity in the fixed bed reactor was 3m/h, and the concentration was 1mol/L sulfuric acid to carry out circulation activation treatment, and the weight ratio of the mixed material and sulfuric acid was 1:40, the activation time at room temperature is 6 hours, then adjust the pH value with lye, so that the pH value of the above solution is 10, and then use sulfuric acid with a line speed of 3m/h after adjusting the pH value to perform circulation activation treatment, and activate at room temperature The time is 6 hours. Take out the activated granular mixture, put it into a vertical tubular roasting furnace, and carry out drying treatment first, the drying temperature is 110 °C, dry for half an hour, and then increase the temperature at a rate of 10 °C per minute, the final roasting temperature It is 500°C and baked for 1 hour. After cooling, the ion adsorption type rare earth adsorbent is finally obtained.

The rare earth adsorbent is used to treat phosphorus chemical wastewater with a phosphorus concentration of 500mg/L, and the adsorption capacity of the rare earth adsorbent for phosphorus can reach 20-25mg/g; after adsorption is saturated, it can be used continuously after regeneration.

Example 2:

The heavy rare earth element content is 1wt%, and the light rare earth element content is 2wt% The ion adsorption type rare earth ore and clay are prepared according to the weight ratio of 10:3, mix uniformly to be a mixture; and add the water of 30% of the weight of the mixture Parts, granulated to obtain a spherical mixture with a diameter of 2.5-10mm; then put the spherical mixture into a rotary roaster for roasting treatment, the roasting temperature is 500 ° C, and roast for 1.5 hours; then roast the mixed material Enter the fluidized bed reactor, be that 2m/h, concentration are 1.5mol/L hydrochloric acid to carry out circulating activation treatment with the linear velocity in the fluidized bed reactor, the weight ratio of this mixture and hydrochloric acid is 1: 20, and the activation time under normal temperature is 5 hours, then adjust the pH value with lye so that the pH value of the above solution is 9, and then use the solution with a linear velocity of 2m/h after adjusting the pH value to carry out circulation activation treatment for 5 hours; take out the activated granular mixture, and It is put into a rotary roasting furnace and firstly dried at a drying temperature of 100°C for half an hour, and then heated at a rate of 10°C per minute to a final roasting temperature of 450°C for 1 hour; after cooling, Finally, the ion adsorption type rare earth adsorbent is obtained.

The rare earth adsorbent is applied to the deep nitrogen and phosphorus removal of urban domestic sewage, and the adsorption capacity of the rare earth adsorbent for nitrogen can reach 15-20mg/g, and the adsorption capacity for phosphorus can reach 12mg/g; Can continue to use.

Example 3:

The content of rare earth element is 0.5wt%, and the content of light rare earth element is 3wt%. The ion adsorption type rare earth ore and clay are prepared according to the weight ratio of 10:4, and the mixture is uniformly mixed; and add 40% water of the mixture weight granulation, to obtain a cylindrical mixture with a diameter of 2.5mm to 10mm and a height of 3mm to 20mm; 2.5 hours; Put the roasting mixture into the fixed-bed reactor again, and be that 4m/h, concentration are 1.5mol/L hydrochloric acid to carry out circulation activation treatment in the fixed-bed reactor with the linear velocity, and the weight ratio of this mixture and hydrochloric acid is 1: 30. The activation time at room temperature is 6.5 hours, then use lye to adjust the pH value to 11, and then perform circulation activation treatment at a line speed of 4m/h for 6.5 hours; take out the activated granular mixture and put it into the mesh belt type In the roasting furnace, the drying process is carried out first, the drying temperature is 120 ° C, drying for half an hour, and then the temperature is raised at a rate of 20 ° C per minute, the final roasting temperature is 550 ° C, and the roasting is 1.5 hours; after cooling, the ion adsorption is finally obtained. type rare earth adsorbent.

The rare earth adsorbent is used to treat fluorine-containing wastewater with a concentration of 500 mg/L, and the adsorption capacity of the rare earth adsorbent for fluorine can reach 16-23 mg/g; after the adsorption is saturated, it can be continuously used after being regenerated.

Claims (4)

1. one kind prepares the method for sewage dephosphorization adsorbent with ion adsorption type re, and it is characterized in that: invention is finished according to the following steps,

(1) raw material preparation: ion adsorption type rare earth ore and clay are prepared by 10: 0.5～4 weight ratio, be mixed into compound;

(2) granulation: 10～40% of its weight of adding moisture content in compound, carry out granulation;

(3) roasting: the compound after the granulation is gone in the roaster, carries out calcination process, and sintering temperature is 500～800 ℃, roasting time 1～3 hour;

(4) activation: the compound after the roasting is gone into reactor, with concentration is that sulfuric acid or the hydrochloric acid of 0.2～2mol/L is made activating solution, and be that the activating solution of 2～5m/h carries out cyclic activation to compound and handles with linear speed in the reactor, the weight ratio of compound and activating solution is 1: 20～50, soak time is 4～8 hours under the normal temperature, regulating activating solution pH value with alkali lye then is 8～12, carries out cyclic activation with above-mentioned same linear speed again and handles 4～8 hours;

(5) drying and roasting: the compound after the activation, go into roaster and carry out the drying processing earlier, baking temperature is 100～120 ℃, dry half an hour, and then heat up with per minute 10-20 ℃ heating rate, final temperature is 400～700 ℃ of following roastings 0.5～2 hour, makes the ion adsorption type re adsorbent after the cooling.

2. according to claim 1ly prepare the method for sewage dephosphorization adsorbent with ion adsorption type re, it is characterized in that: in the described ion adsorption type rare earth ore, heavy rare-earth element content is 0.06～5wt%, and LREE content is 0.1～3wt%.

3. the method for preparing the sewage dephosphorization adsorbent with ion adsorption type re according to claim 1, it is characterized in that: described preparation and the compound that mixes carry out granulation, cause diameter to be 2.5～10mm, highly to be that cylinder or the diameter of 3～20mm is the spheroid of 2.5-10mm.

4. describedly prepare the method for sewage dephosphorization adsorbent with ion adsorption type re according to claim 1,2 or 3, it is characterized in that: described reactor is fixed bed reactors or fluidized-bed reactor.

Images