TWI458835B - Method for recycling platinum from platinum waste - Google Patents

Description

Method for recovering platinum from platinum-containing waste

This invention relates to a platinum metal recovery process, and more particularly to a process for recovering platinum from platinum-containing waste.

Platinum (Platinum) has an average content of only 0.002g/t in the earth's crust, while the more common precious metal gold has an average content of 0.004g/t in the earth's crust, and the average content of silver in the earth's crust is 0.07g/t. Platinum precious metals are more rare than gold and silver. Platinum precious metals are now widely used in various industries such as electronics, chemistry, glass, automotive, aerospace, petroleum, environmental protection, laboratory utensils, surface treatment, jewelry. , medical, currency and other fields. At present, the annual demand for platinum metal in the world has exceeded the supply. The current price of platinum metal is initially estimated at NT$1,653,600 per kilogram. In addition, platinum metal is not easy to refine from raw ore, which makes platinum metal expensive. . Since China does not produce platinum metal at present, all domestic platinum resources must be imported from abroad. Therefore, how to recover and refine platinum resources from discarded platinum products has become an important issue for China to guarantee the supply of platinum resources.

In addition, the domestic patents related to platinum, such as the Republic of China patent application number: 090117860, are mainly for the recycling method of valuable platinum group metals in waste vehicle waste catalyst, grinding and screening of waste vehicle waste catalyst, using 105 °C About 1:1 aqua regia soaked the crushed waste vehicle waste catalyst and stirred for a suitable time to dissolve the platinum group metal and the basic metal After solution into the liquid phase, after the solid-liquid separation, the solution is diluted by about 15 to 20 times, and the pH is adjusted to about 2 to 3. The metal and the platinum group metal are reduced in the solution to form a metal precipitate by metal replacement. The liquid filtered solid is added to sulfuric acid to dissolve and remove excess zinc powder and basic metal precipitate, and the resulting platinum group metal precipitate is added to the aqua regia to dissolve the platinum group metal, and then hydrochloric acid and water are added to remove the nitric acid and hydrochloric acid. After adding hydrochloric acid to dissolve the platinum group metal, the DOS ultrasonic shock extraction is used, and the obtained extract is added to the hydrochloric acid for washing by the solvent generated by the multistage extraction of TBP, and water is added for the final multi-stage ultrasonic shock back extraction. , you can get a platinum enrichment solution.

In summary, according to the patent search of the Republic of China, the Republic of China application number 090117860 is for the valuable platinum group metal enrichment liquid in the scrap vehicle waste vehicle. The procedure is complicated and there is no purification and recovery of platinum metal technology. At present, no related patents and technologies have been found in China. The platinum metal is purified and recovered for platinum-containing waste to obtain high-purity platinum metal products. Therefore, the present invention can provide domestic related industries as resource recovery platinum-containing waste. in accordance with.

In view of the above problems of the prior art, the object of the present invention is to provide a method for recovering platinum from platinum-containing waste, to avoid waste of platinum metal resources, and to solve the environmental pollution problem caused by platinum-containing waste, and further To achieve the dual purpose of reducing the amount of platinum-containing waste and sustainable use of resources.

According to the object of the present invention, a method for recovering platinum from platinum-containing waste is provided, which comprises the steps of: mixing granular granulated platinum waste with an impregnating agent according to a solid-liquid ratio of 0.02 g/ml to 0.1 g/ml, and An oxidizing agent is added to perform an immersion etching reaction to obtain a platinum-containing immersion liquid; a platinum-containing immersion liquid is filtered to obtain a platinum-containing filtrate; and ammonium chloride is added to the platinum-containing filtrate to carry out a precipitation reaction to obtain a platinum-containing compound.

Preferably, the impregnating agent comprises hydrochloric acid.

Preferably, the concentration of hydrochloric acid may be from 1 N to 7 N.

Preferably, the oxidant comprises hydrogen peroxide.

Preferably, the platinum compound can be ammonium chloroplatinate.

As described above, the method for recovering platinum from platinum-containing waste according to the present invention may have one or more of the following advantages:

(1) The method for recovering platinum from platinum-containing waste can not only avoid the discarding of the platinum-containing waste, but also cause harm to the human body and the environment, and at the same time, achieve the effect of the sustainable circulation of the valuable resources contained therein.

(2) The present invention can reduce the dependence on overseas resources and increase the overall development of the country by recycling the platinum-containing waste to obtain a platinum compound (ammonium chloroplatinate).

(3) By the method of the present invention, the steps of platinum waste resource recovery, processing time and drug consumption can be greatly reduced, and valuable platinum metal can be efficiently recovered to optimize waste resource recovery efficiency.

S11~S13‧‧‧Step process

Figure 1 is a flow chart of a method for recovering platinum from platinum-containing waste according to the present invention.

Fig. 2 is an analysis diagram of the impregnation recovery rate of the platinum metal of the present invention.

Fig. 3 is an analysis diagram of the precipitation recovery rate of the platinum metal of the present invention.

Fig. 4 is a crystal phase diagram of a platinum-containing compound obtained by purification and recovery of the present invention by scanning electron microscopy.

The technical features, contents, and advantages of the present invention, as well as the advantages thereof, will be apparent to the inspectors of the present invention. The present invention will be described in detail with reference to the accompanying drawings.

Please refer to FIG. 1 , which is a flow chart of a method for recovering platinum from platinum-containing waste according to the present invention. In the figure, the method may include the following steps: Step S11, mixing the granular platinum-containing waste with the impregnating agent according to the solid-liquid ratio of 0.02 g/ml to 0.1 g/ml, and adding an oxidizing agent to perform the impregnation and dissolution reaction to obtain Platinum-containing impregnation solution. In step S12, the platinum-containing impregnation liquid is filtered to obtain a platinum-containing filtrate. And in step S13, ammonium chloride is added to the platinum-containing filtrate to carry out a precipitation reaction to obtain a platinum-containing compound. By the method of the present invention, the platinum-containing waste can be recycled to obtain a platinum compound, thereby optimizing the waste resource recovery efficiency.

Further, the above impregnating agent may comprise hydrochloric acid; the oxidizing agent may comprise hydrogen peroxide; and the precipitating agent may comprise ammonium chloride. Among them, the platinum compound purified by the method of the present invention may be ammonium chloroplatinate. The above is merely an example embodiment, but should not be limited thereto.

It is worth mentioning that, in the embodiment of the present invention, before the impregnation and erosion, before the step S11, the platinum-containing waste may be subjected to crushing and grinding steps, and after the crushing and grinding, in order to obtain smaller particles and ascend the particles. The powder sample of the impregnation recovery can be sieved by a 20-mesh screen with an ultrasonic wave shaker to obtain fine-grained platinum-containing waste. Among them, the finer the particles of the platinum-containing waste are, the better the effect of eluting the platinum metal.

In step S11, the sieved platinum-containing waste is placed in various acid or alkali liquids, and the solid phase platinum metal can be impregnated and dissolved into a liquid phase to facilitate subsequent platinum metal recovery. Work is going on. Therefore, the present invention will use hydrochloric acid as an impregnating agent to impregnate and dissolve the platinum-containing waste, and since the oxidizing agent can enhance the oxidizing ability of the hydrochloric acid impregnated metal platinum, hydrogen peroxide is used as an oxidizing agent to grind the obtained granular platinum-containing waste. Hydrochloric acid and hydrogen peroxide are added to produce a platinum-containing impregnation solution. Wherein, the platinum-containing waste and the impregnating agent may be added in the range of 1 g/50 ml to 5 g/50 ml, and the solid-liquid ratio thereof is 0.02 g/ml to 0.1 g/ml, preferably 0.06 g/ml. That is, the addition amount of the impregnating agent added to the 3 g of the platinum-containing waste is preferably 50 ml.

It is worth mentioning that the concentration of hydrochloric acid may be from 1 N to 7 N, preferably 6 N. The 1 mol of platinum-containing waste needs to be added with 2 mol of hydrogen peroxide to carry out the reaction. Therefore, the target platinum metal in the oxidation of 1 g of the platinum-containing waste requires 0.0001 mol of hydrogen peroxide, so the theoretical addition content of hydrogen peroxide is 0.0034g. The molecular weight of hydrogen peroxide is 34 g/mole, and the present invention uses 30% hydrogen peroxide, so the theoretical value to be added is 0.01 g. Here, the present embodiment is preferably added with 10 times hydrogen peroxide. Amount to carry out an oxidation reaction. The above is only a preferred embodiment, but should not be construed as limiting.

Further, the impregnation temperature of the platinum-containing waste to be immersed in hydrochloric acid and hydrogen peroxide may be 60 ° C to 100 ° C, preferably 70 ° C, and the immersion time may be 15 minutes to 1 hour, preferably 45 minutes. . The above are only examples of implementations, but should not be construed as limiting. Therefore, after 6N hydrochloric acid, hydrogen peroxide 10 times theoretical addition amount, solid-liquid ratio 0.06g/ml, and heating to 70 ° C for 45 minutes under stirring, a preferred platinum-containing immersion liquid can be obtained, and under such conditions, preliminary The target platinum metal is dissolved in the immersion liquid in an ionic state to obtain a liquid phase platinum metal, and the impregnation recovery rate (%) of the platinum metal can reach 100%, and the impregnation result is as shown in FIG.

Further, in step S12, the platinum-containing immersion liquid is subjected to solid-liquid separation step, Larger solid particles can be settled in the liquid phase solution by utilizing the physical properties of the solid-liquid two phases. Generally, the method of solid-liquid separation may include gravity method, pressurization method, decompression method, centrifugal separation, etc., but the present invention adopts a vacuum decompression method as a solid-liquid separation method for a platinum-containing impregnation liquid, but does not limit. By filtering the platinum-containing impregnation liquid by this solid-liquid separation method, a platinum-free filter residue and a platinum-containing filtrate can be obtained.

However, in the process of impregnating the platinum-containing waste powder, other metal components are also impregnated and dissolved. In order to improve the efficiency and purity of the target platinum metal recovery, a purification step is required to reduce the valuable metals in the impregnation liquid. Recycling in the form of a metal or compound. Generally, the purification step of the platinum metal may include three methods, such as a precipitation method, a reduction method or a replacement method, wherein the precipitation method mainly comprises adding a chemical agent to form a metal ion to form a compound having a small solubility, and forming a precipitate in the solution. In the embodiment of the present invention, since the platinum compound has a low solubility characteristic in the chemical agent, the precipitation method is used to purify and recover the platinum metal. Therefore, in step S13, ammonium chloride is used as a precipitating agent to be added to the platinum-containing filtrate, and the reaction is allowed to stand at room temperature for 10 minutes to 24 hours to complete the purification and recovery of the target platinum metal. Among them, the preferred precipitation time can be 24 hours.

It is known that the platinum metal content of the 1 L platinum impregnation liquid is 598.6 mg, and the molecular weight of ammonium chloride is 53.5 g/mole. If the precipitation reaction is carried out with 20 ml of the platinum-containing impregnation liquid, 0.00157 g of chlorination is added. Ammonium. Here, in this embodiment, the precipitation reaction is preferably carried out in an amount of 100 times ammonium chloride added. Under this condition, the precipitation recovery (%) of the platinum metal can be 100%, and the precipitation result is shown in Fig. 3. The precipitation reaction can precipitate the target platinum metal ion in the platinum-containing filtrate of the present invention, and precipitate the compound with less solubility into the solution to form ammonium chloroplatinate ((NH ₄ ) ₂ PtCl ₆ ). Platinum compound.

Furthermore, in order to confirm that the platinum element can be obtained by the above-described procedure, the present invention analyzes by using a scanning electron microscope (SEM) and an energy dispersive spectrometer (EDS) to identify the present invention. The type of the chemical element in the platinum-containing compound is as shown in Fig. 4, which is a crystal phase diagram of the platinum-containing compound obtained by the purification and recovery of the present invention by scanning electron microscopy. The weight percentage of the platinum metal in the pure (NH ₄ ) ₂ PtCl ₆ is 44% by weight, and as a result of the analysis, it can be understood that the platinum-containing compound contains only 54.72% by weight of the chlorine element (Cl) and 45.28% by weight. There are no other chemical elements in the two elements of platinum (Pt), as shown in Table 1. Therefore, the platinum-containing compound obtained by the recovery method of the present invention can be as high as 100%, which means that the platinum waste resource recovery efficiency is optimized.

In summary, the method for recovering platinum from the platinum-containing waste according to the present invention is firstly obtained by impregnating the waste powder obtained by polishing the platinum-containing waste with a specific solid-liquid ratio in the impregnating agent and the oxidizing agent. The metal is dissolved in the impregnation liquid and separated by solid-liquid two-phase physical properties to obtain a platinum-containing filtrate. Next, in order to improve the efficiency and purity of the target platinum metal recovery, a specific precipitant is added to the platinum-containing filtrate for pure purification. The platinum metal in the platinum-containing filtrate is recovered in the form of a metal or a compound to obtain a platinum-containing compound. By the method of the invention, the steps of platinum waste resource recovery, treatment time and drug consumption can be greatly reduced, and the valuable platinum metal can be effectively recovered to optimize the waste resource recovery efficiency. In this way, in addition to avoiding the arbitrary disposal of platinum-containing waste and harm to the human body and the environment, it can also achieve the effect of sustainable circulation of valuable resources contained therein, thereby reducing dependence on overseas resources and increasing the overall nationality. Development.

The above is intended to be illustrative only and not limiting. Any equivalent modifications or alterations to the spirit and scope of the invention are intended to be included in the scope of the appended claims.

S11~S13‧‧‧Step process

Claims (4)

A method for recovering platinum from platinum-containing waste, comprising the steps of: mixing a granular platinum-containing waste with an impregnating agent according to a solid-liquid ratio of 0.02 g/ml to 0.1 g/ml, and adding an oxidizing agent; Immersing the dissolution reaction to obtain a platinum-containing impregnation liquid, wherein the oxidant comprises hydrogen peroxide, the impregnation reaction is impregnated at 70 ° C, and the immersion time is 15 minutes to 1 hour; and the platinum-containing impregnation solution is filtered to A platinum-containing filtrate is obtained; and ammonium chloride is added to the platinum-containing filtrate to carry out a precipitation reaction to obtain a platinum-containing compound. The method of claim 1, wherein the impregnating agent comprises hydrochloric acid. The method of claim 2, wherein the hydrochloric acid concentration is 1N to 7N. The method of claim 1, wherein the platinum compound is ammonium chloroplatinate.