TW201813929A - Method of synthesizing homogeneous granular basic cupric carbonate and copper oxide by using fluidized-bed crystallization technology - Google Patents

Abstract

The present invention relates to a method of synthesizing homogeneous granular basic cupric carbonate and copper oxide by using fluidized-bed crystallization technology. In addition to a high efficiency of copper ions removal from water, the method also can reduce the usage of chemical agents. Furthermore, this method has no need to apply heterogeneous carriers in the fluidized-bed reactor. By varying the operation conditions of pH, molar ratio of copper to carbonate, copper surface loading and hydraulic retention time, copper ions can be removed from wastewaters in a fluidized-bed homogeneous crystallization (FBHC) system by recovering crystallization of copper salts. This method has a very high application potential because of high treatment efficiency and crystal purity.

Description

Method for synthesizing homogeneous basic copper carbonate and copper oxide crystal by fluidized bed crystallization technique

The invention relates to a method for synthesizing homogeneous basic copper carbonate and copper oxide crystals, in particular to a method for synthesizing homogeneous basic copper carbonate and copper oxide crystals by fluidized bed crystallization technology.

The development of high-tech industries is often accompanied by the discharge of heavy metal-containing copper wastewater. In the past, copper removal technologies mainly included technologies such as chemical coagulation, adsorption, biological treatment, and fluidized bed crystallization. At present, the choice of copper removal method is mainly based on chemical coagulation. In recent years, the fluidized bed crystallization technology has been paid attention to in the removal of copper, and it has gradually been applied in sewage plants. The chemical coagulation and sedimentation is the use of a precipitating agent, by adding an alkali solution to adjust the appropriate pH value, reacting with copper ions to form a solid precipitation solution, and adding a high-molecular flocculant to achieve the purpose of copper removal by a coprecipitation mechanism. . Although chemical coagulation and sedimentation has simple operation and good copper removal effect, it requires a large amount of chemicals to be added during the copper removal process, and the solid waste produced by the solid waste has a high water content (ie, high-hydrogen copper sludge), which has an impact on the environment. The purity of the solid is low, which also causes trouble and harm to the subsequent solid-liquid separation and recovery. The adsorption method is to add an adsorbent to the copper-containing solution. Because the surface of the adsorbed material is opposite to the adsorbed charge, it will attract each other under the action of positive and negative charges, but does not directly bond with the surface of the adsorbent, but is electrostatically attached. On the surface of the adsorbent. Although the adsorption method has the simple operation of removing copper, the adsorption material needs to be desorbed to extract concentration or transport, and the number of regeneration of the adsorbed material is limited, so it is still in the development stage. The biological treatment achieves the purpose of copper removal by connecting the anaerobic tank and the aerobic tank in series, but the biological treatment method cannot handle the high concentration of the copper-containing solution, and a large amount of biological sludge is generated.

The processing apparatus of the "fluidized bed crystallization technique" includes a fluidized bed reaction tank having a support therein. The waste water to be treated flows upward from the bottom of the reaction tank, so that the support fluidizes at a certain upward flow speed, and the reaction tank is connected to the chemical inlet for feeding the medicament, so that the pollutant in the waste water is supported in the reaction tank. Crystallization, thereby removing anions or metal ions from the wastewater and recovering the reusable metal particles. However, the conventional "fluidized bed crystallization technology" requires the addition of a support (such as strontium sand, brick powder, etc.) to the crystallization in the reaction tank, resulting in a heterogeneous support component in the metal crystal, and the purity of the crystal is not good. Negative impact on the value of reuse.

Accordingly, the main object of the present invention is to provide a method for synthesizing homogeneous basic copper carbonate and copper oxide crystal by fluidized bed crystallization technology, which adopts a technique of homogeneous nucleation crystallization, and the obtained crystal has high purity. Conducive to subsequent processing applications, but also has the advantages of high efficiency, low cost, no sludge.

According to an embodiment of the invention, the method for synthesizing homogeneous basic copper carbonate and copper oxide crystals by a fluidized bed crystallization technique comprises: providing a fluidized bed reaction tank having a lower section and an upper section, the lower section a solution inlet port and a drug inlet port are provided, the upper section is provided with a water outlet, and a flow line is provided between the lower section and the upper section, the reaction tank does not have a heterogeneous support; the copper solution is granulated and granulated the mixing tank of individual drug reaction solution was introduced from the inlet orifice to the inlet orifice agent, wherein the pH of the reaction (pH _e) controlled at between 5 and 10, the copper-containing solution sectional load (L) control Between 1 and 5 kg m ^-2 h ^-1 , the granulating agent is carbonate and the molar concentration ratio (C _CO3 /C _Cu ) of the carbonate relative to the copper ion of the copper solution is controlled Between 1 and 4; flowing a copper-containing solution mixed with the granulating agent from the lower portion of the reaction vessel to the upper portion of the reaction vessel; and passing the copper-containing solution mixing the granulating agent through the reflux conduit Reflux to the lower stage for recycling to make copper ions in the copper-containing solution The reaction to produce the pharmaceutical agent particles of basic copper carbonate and / or homogenous copper oxide particles.

In a preferred embodiment, the hydraulic retention time is controlled between 10 and 50 minutes to achieve high copper ion removal and crystallization ratio.

In a preferred embodiment, the copper-containing solution is mixed with the granulating agent in the reaction tank to produce a basic copper carbonate homogeneous crystal particle before the copper-containing solution in which the granulating agent is mixed is subjected to a reflux cycle. As the support, and the initial particle height control of the control particles is between 0.25 and 0.75 of the length of the lower section of the reaction tank to obtain a high copper ion removal rate and a crystallization ratio.

In a preferred embodiment, the pH of the reaction is controlled to be between 7 and 8, so that the fluidized bed homogenization granulation process is maintained at an appropriate pH value to obtain a higher copper ion removal rate and crystallization ratio. .

In a preferred embodiment, the feed molar concentration ratio (C _CO3 /C _Cu ) is controlled between 1.5 and 2.5, and the cross-sectional load (L) of the copper-containing solution is controlled between 2-4 In order to obtain high copper ion removal rate and crystallization ratio.

Other objects, advantages and features of the present invention will become apparent from

The invention provides a method for synthesizing homogeneous basic copper carbonate and copper oxide crystal by fluidized bed crystallization technology, which utilizes granulation to remove and recover copper in a copper-containing solution (for example, copper-containing wastewater). It can reduce the use of chemical agents, and does not require the use of a support, and the obtained basic copper carbonate and copper oxide particles can be further reused. Furthermore, the method of the present invention can treat wastewater having a copper content of 100-2000 ppm and effectively remove the copper content to an average concentration of 10 ppm or less, thereby being most suitable for treatment of heavy metal-containing wastewater generated in the electroplating process or Groundwater treatment with other copper-containing metals to solve the pollution problem.

Referring to Figure 1, the process of the present invention first provides a fluidized bed reaction tank 10 having a tubular lower section 12 and a tubular upper section 14, the upper section 14 having an outer diameter greater than the outer diameter of the lower section 12. The lower section 12 is provided with a solution inlet 16 and a medicament inlet 18, the upper section 14 is provided with a water outlet 20, and a lower return line 22 is formed between the lower section 12 and the upper section 14. In the present embodiment, the bottom portion of the lower portion 12 of the reaction tank 10 has a conical shape to facilitate uniform dispersion of the return flow force. A pH value detector 24 is provided at the water outlet 20 to monitor the pH of the flow port while collecting water samples for water quality analysis. Next, the copper-containing solution (for example, copper-containing wastewater) 30 and the granulating agent 32 are separately introduced into the lower portion 12 of the reaction vessel 10 from the solution inlet port 16 and the drug inlet port 18 by means of the pumps 26 and 28. Next, the copper-containing solution 30 mixed with the granulation agent 32 flows from the lower stage 12 to the upper stage 14, and thereafter, the copper-containing solution 30 in which the granulation agent 32 is mixed is returned to the lower stage 12 via the return line 22 to The circulation is performed so that the copper ions in the copper-containing solution 30 are granulated with the granulation agent 32. In the present embodiment, the granulating agent 32 is a carbonate (for example, sodium carbonate), which uses a copper ion in the copper-containing solution 30 to produce a poorly soluble salt, and utilizes the characteristics of the granulation reaction to control the supersaturation. In a suitable range, the reaction in the fluidized bed reaction tank 10 is carried out to remove copper ions in the copper-containing solution 30.

According to the method of the present invention, the pH value in the reaction tank (pH _e ), the molar ratio of the granulating agent to the copper ion of the copper-containing solution, the cross-sectional load (L) of the copper-containing solution, and the reactor treatment The hydraulic retention time of the copper wastewater and the initial static bed height (the height of the particles accumulated in the reactor when the fluidized bed is at rest) will affect the copper ion removal rate (excluding copper efficiency) and particle stability in the copper-containing solution 30, respectively. The subsequent granulation rate (crystallization ratio). According to the test result, the pH (pH _e) should be controlled between 5 and 10, the copper-containing solution sectional load (L) should be controlled between 1 and 5 kg m ^-2 h ^-1, granulating agents relative The feed molar concentration ratio (C _CO3 /C _Cu ) of the copper ion containing copper solution should be controlled between 1 and 4, and the hydraulic retention time should be controlled between 10 and 50 min. Further, in the method of the present invention, the copper-containing solution 30 and the granulating agent 32 may be introduced into the reaction tank 10 to be mixed with the basic copper carbonate to produce the homogeneous copper carbonate particles in a state where the reflux is operated or not. As a support, it is used to provide sufficient crystal growth surface area to facilitate the adhesion of newly formed crystal particles to regenerate new particles, so as to avoid the formation of gelatinous precipitates containing a large amount of water, which should be controlled in the reaction tank. The length of the lower 12 tube is between 0.25 and 0.75. In this embodiment, the lower section of the reaction vessel 12 has a length of about 80 cm, and the height of the granular bed should be controlled between 20 and 60 cm.

Referring to Figure 2, the initial copper concentration of the copper-containing solution is 1300 ppm, the feed molar ratio of the granulating agent to the copper-containing solution (C _CO3 /C _Cu ) is 2, and the hydraulic retention time (HRT) is 16.7. In the operating conditions of min, the pH value in the reaction tank (pH _e ) changes the effect on the crystallization ratio (CR%) and the copper removal efficiency (TR%). Experiment found that pH control in the reactor is between 6 and 8 is obtained basic copper carbonate particles (see FIG. 3), is obtained when the pH value (pH _e) copper oxide particles of more than 8 (see FIG. 4). Further, it is found from FIG. 2, when the pH of the reaction (pH _E) is between 5 and 10, to remove the copper ions in the copper-containing wastewater, and the high crystalline fraction, in particular, pH (pH _e ) When between 7 and 8, respectively, a copper removal efficiency and a crystallization ratio of more than 90% are obtained.

Referring to Figure 5, which shows the initial copper concentration in the copper solution was 1600 ppm, pH (pH _e) is 7 ± 0.2 ,, hydraulic retention time (HRT) of 16.7 min in the operating condition, the granulation agent containing a relatively The effect of the molar concentration ratio (C _CO3 /C _Cu ) of the copper solution on the crystallization ratio (CR%) and the copper removal efficiency (TR%). It has been found through experiments that when the feed molar concentration ratio (C _CO3 /C _Cu ) is controlled between 1 and 4, high copper ion removal rate and crystallization ratio can be obtained, especially the feed molar ratio (C _CO3 /C). _{When Cu} is between 1.5 and 2.5, the copper ion removal rate and the crystallization ratio after particle stabilization are optimal (about 95% copper removal efficiency and crystallization ratio).

Referring to Figure 6, there is shown that the initial copper concentration in the copper-containing solution is 1300 ppm, the feed molar concentration ratio (C _CO3 /C _Cu ) of the granulating agent relative to the copper-containing solution is 2, and the pH value is (pH _e ) In the operating conditions of 7±0.2 and hydraulic retention time (HRT) of 16.7 min, the cross-sectional load (L) of the copper-containing solution changed the effect on the crystallization ratio (CR%) and the copper removal efficiency (TR%). It has been found through experiments that when the cross-sectional load (L) of the copper-containing solution is controlled between 1 and 5 kg m ^-2 h ^-1 , high copper ion removal rate and crystallization ratio can be obtained, in particular, the cross-sectional load of the copper-containing solution (L) When it is between 2-4, the copper ion removal rate is the best as the crystallization ratio after the particles are stabilized.

Referring to Figure 7, there is shown that the initial copper concentration in the copper-containing solution is 1300 ppm, the feed molar concentration ratio (C _CO3 /C _Cu ) of the granulating agent relative to the copper-containing solution is 2, and the pH value is (pH _e ) In the operating conditions of 7 ± 0.2, the hydraulic retention time (HRT) changes the effect on the crystallization ratio (CR%) and the copper removal efficiency (TR%). It has been found that high copper ion removal rate and crystallization ratio can be obtained when the hydraulic retention time (HRT) is controlled between 10 and 50 min.

Referring to FIG. 8, there is shown in the granulation agent relative molar concentration ratio of the copper-containing feed solution of (C _CO3 / C _Cu) of 2.35, pH (pH _e) of 7 ± 0.2, hydraulic retention time (HRT) of 16.7 min, the cross-sectional load of the copper-containing solution L _Cu is 2.7 kg m ^-2 h ^-2 in the operating conditions, the initial homogeneous particle static bed height (cm) changes to the crystallization ratio (CR%) and copper removal efficiency (TR%) Impact. It has been found through experiments that the basic carbonate particle is synthesized as a support by a fluidized bed homogenization crystallization reactor, and the initial packed bed height is controlled between 0.25-0.75 of the length of the lower section of the reaction tank (in this embodiment When between 20 and 60 cm height, sufficient crystal growth surface area is provided to obtain high copper ion removal rate and crystallization ratio.

It can be seen from the above results that the present invention adopts fluidized bed homogenization crystallization technology, and adjusts water quality conditions including pH, feed molar ratio, cross-section load, hydraulic retention time and the like under optimal conditions, and can rectify copper-containing wastewater to efficiently remove copper in water. The ions are effectively reused in accordance with the discharge water standard and the recovery of basic copper carbonate and copper oxide crystals. Furthermore, the method of the invention adopts a homogeneous nucleation crystallization technique, and does not need to first add a heterogeneous support in the fluidized bed reaction tank, so that the obtained crystal has high purity, which is advantageous for subsequent processing applications. Therefore, the method of the invention can not only replace the chemical coagulation to achieve an excellent treatment effect, but also avoid the defects of the traditional chemical or biological methods, and achieve the purpose of product resource, and has the advantages of high efficiency, low cost, no sludge, and the like. .

In the foregoing specification, the invention has been described in terms of a particular embodiment, and various changes or modifications may be made in accordance with the features of the invention. Therefore, obvious substitutions and modifications may be made by those skilled in the art, and will still be incorporated in the scope of the claimed invention.

10‧‧‧Reaction tank
12‧‧‧ lower section

14‧‧‧上段
16‧‧‧ solution inlet

18‧‧‧Pharmaceutical inflow
20‧‧‧Water outlet

22‧‧‧Return line
24‧‧‧pH detector

26‧‧‧
28‧‧‧

30‧‧‧ copper-containing solution
32‧‧‧Plasting Agent

1 is a schematic view of a fluidized bed reaction tank in accordance with an embodiment of the present invention.

2 is a graph showing the relationship between the pH value (pH _e ) in the reaction tank and the effect of the crystallization ratio (CR%) and the copper removal efficiency (TR%) in the fluidized bed homogeneous granulation step.

FIG 3 based control pH in the reaction vessel (pH _e) Analysis of X-ray diffraction graph in FIG analyzer (XRD) detected between 6 to 8, wherein the display recovered basic copper carbonate particles.

FIG 4 based control pH (pH _e) to FIG. 8 above analysis curve X ray diffraction analyzer (XRD) is detected, wherein the display recovered copper oxide particles.

Figure 5 is a graph showing the relationship between the feed molar concentration ratio and the crystallization ratio (CR%) and the copper removal efficiency (TR%) in the fluidized bed homogenization granulation step.

Figure 6 is a graph showing the relationship between the cross-sectional load (L) of the copper-containing solution versus the crystallization ratio (CR%) and the copper removal efficiency (TR%) in the fluidized bed homogeneous granulation step.

Figure 7 is a graph showing the relationship between hydraulic retention time (HRT) versus crystallization ratio (CR%) and copper removal efficiency (TR%) in a fluidized bed homogeneous granulation step.

Figure 8 is a graph showing the relationship between the initial static bed height to crystallization ratio (CR%) and the copper removal efficiency (TR%) in the fluidized bed homogenization granulation step.

no

Claims (6)

A method for synthesizing homogeneous basic copper carbonate and copper oxide crystals by a fluidized bed crystallization technique, comprising: providing a fluidized bed reaction tank having a lower section and an upper section, the lower section being provided with a solution inlet and a medicament The inlet port is provided with a water outlet, and a return line is provided between the lower section and the upper section, and the reaction tank does not have a heterogeneous support; the copper-containing solution and the granulation agent are separately from the solution inlet port and the agent introduced into the inflow port of the fluid bed reactor vessel mixing, wherein the reaction pH (pH _e) controlled at between 5 and 10, the copper-containing solution sectional load (L) between the control 1-5 Between kg m ^-2 h ^-1 , the granulating agent is carbonate and the feed molar ratio (C _CO3 /C _Cu ) of the carbonate to the copper ion of the copper solution is controlled between 1 and 4 Between 0 mg/L; the copper-containing solution mixed with the granulating agent flows from the lower portion of the reaction tank to the upper portion of the reaction tank; and the copper-containing solution in which the granulating agent is mixed is refluxed through the reflux line Down to the next stage to cycle copper ions and granulating agents in copper-containing solutions The reaction to produce basic copper carbonate and / or homogenous copper oxide particles. The method of claim 1, wherein the hydraulic retention time is controlled between 10 and 50 min. The method according to claim 1, wherein the copper-containing solution and the granulating agent are first mixed in the reaction tank to produce basic copper carbonate homogeneous crystal particles as a support, and the initial static bed height of the particles is controlled. It is controlled between 0.25-0.75 of the length of the tube in the lower part of the reaction tank. The method of claim 1, wherein the reaction pH (pH _e ) is controlled between 7-8. The method of claim 1, wherein the feed molar concentration ratio (C _CO3 /C _Cu ) is controlled between 1.5 and 2.5. The method of claim 1, wherein the cross-sectional load (L) of the copper-containing solution is controlled to be between 2-4 kg m ^-2 h ^-1 .