1. High temperature treatment to recover tungsten cobalt method

Super hard alloy is made of tungsten, cobalt and carbon powder mixture is processed into molded sintering. The super-hard alloy high-temperature treatment method developed by Japan New Metal Co., Ltd. can recover tungsten-cobalt recycled powder with an annual output of 80 tons. High temperature treatment process for producing recycled powder:

After the super-hard alloy scraps are washed, the heat treatment is performed in an inert gas at a high temperature of 1800 to 2300 ° C, and the cobalt in the super-hard alloy is in a sponge state which is easy to be powdered. At the heat treatment temperature, the cobalt in the super-hard alloy is not in a sponge state below 1800 °C, and the tungsten carbide in the alloy above 2300 °C will decompose and form a third phase, and the result is not good.

The heat-treated lumps were coarsely crushed to -850 μm by a jaw crusher or a drum crusher , and then finely pulverized into a regenerated powder.

The regenerated powder obtained by this method tends to grow easily during sintering due to the coarse particle formation process. There is almost no change in the cobalt content and carbon content after treatment, and only the amount of impurities iron and silicon increases, which has no effect on the manufacture of cemented carbide. The particle size of the regenerated powder may be finely pulverized to 1 μm or less depending on the pulverization conditions.

This method uses a relatively easy process, does not damage the original composition of the super-hard alloy, any type of super-hard alloy can reproduce a certain size of powder, without special equipment, is an economic recovery method. Compared with the previous method of reusing and refining chemical reagents, it has great advantages.

Second, waste beverage aluminum can coating peeling method

Waste recycling aluminum cans, the low melting recoveries, poor quality, the key is aluminum coatings used inside and outside caused. The first is the low recovery of fusion, the polymer compound due to heat when melting of the coating to promote oxidation of aluminum, the amount of reducing metal recycling; Second poor quality, because of the pigment used in the coating of titanium oxide (white with agent), an impurity element It is one of the causes of defects when it is mixed in the aluminum melt to form a coarse intervening material.

In order to remove the coating material causing these factors, a method of heating and baking is used, but there is a problem that the apparatus is large in size and the titanium of the pigment is not removed.

Japan uses a solvent chemistry method (swelling and stripping method) to eliminate the coating on the aluminum can. With the newly developed coating stripping device, the device strips the coating, and the recovery rate of the aluminum can is reduced, which is improved when the non-peeling coating is melted, and is prevented. The coating contains titanium components, and the aluminum melt composition is almost the same as the analytical value of the commercially available aluminum can body material (3004). The stripping device and the removal of the coating further increase the recovery rate of aluminum and improve the quality of the recovered aluminum material, and thus are widely used. Disposal of waste aluminum cans is stripped of paint at an hourly throughput of approximately 200 kg ∕ h.

In addition to being used for peeling off beverage aluminum can coatings, it can also be used for stripping and removing paints such as aluminum window frames, aluminum foils, and laminates of aluminum sheets.

The principle of swelling and peeling: coatings for aluminum cans, generally for external use, cleaning coatings and white coatings; interior cleaning with a coating

material. The coating composition is a polymer material which is used to peel off the coating due to swelling of the solvent. That is, the swelling force of the polymer coating which is absorbed by the solvent and swollen exceeds the adhesion of the coating itself to the aluminum can material, and the coating peeling becomes possible.

The process of swelling and peeling:

(1) Pre-processing. In order to facilitate the removal of the coating, the recovered waste aluminum can was cut into pieces of 1 ∕ 10 cans and placed in a cage.

(2) Stripping process. Dip the cage into the stripper. The rotation is performed, and the stripping liquid swells the coating to carry out a chemical reaction, and the aluminum sheets in the rotation rub against each Other to promote peeling.

(3) Rinsing process. In the same manner as the peeling step, half of the liquid was transferred into the stripping liquid to separate the peeled paint from the aluminum sheet.

(4) Steam drying process. The cage is rotated in the steam, and the stripping liquid adhered on the surface of the aluminum sheet is evaporated, and the stripped liquid of the gasification is coagulated and recovered by a water-cooled tube, and recycled.

(5) Drying process. The steam temperature in the step (4) is further increased, and the stripping liquid remaining on the aluminum sheet is further evaporated and dried.

(6) Compression processing steps. The aluminum sheet after the swelling and peeling is taken out from the cage, compressed by a press, and then sent to a melting step to smelt and recover the aluminum material.

The coating stripping solution used is dichloromethane, formic acid, and a mixed solution of halogenated acetic acid which promotes the peeling action. This mixed liquid has a large swelling effect on the aluminum can coating and has high peeling performance.

Third, heavy oil ash vanadium method

The oil contains traces of vanadium . Japan in the late 1950s, the power company's main fuel shift from coal oil, designed to burn heavy oil thermal power generation, better, resulting in a large heavy oil waste ash. Xinxing Chemical Industry Co., Ltd. researched and successfully processed heavy oil ash and vanadium extraction process, changed the situation of relying on imported vanadium. In 1973, it built a new workshop, concentrated heavy oil ash in the country, and extracted vanadium to recover valuable metals.

Heavy putty is the soot collected by the dust collector generated when the heavy oil boiler is burned, also called dust collecting coal. There is also the attachment of the bottom of the water tube boiler, and the combustion shell taken out during regular maintenance is also called boiler slag.

The main component of soot is unburned charcoal, which contains a low grade of vanadium and nickel . When it is recycled, it must be pretreated, washed with water to remove soluble components, and then calcined at 800-1000 °C. After calcination, the weight is reduced to 1∕ 10 and the vanadium grade is increased accordingly. The combustion shell is mixed with alkali to be calcined, and then the vanadium is extracted with water, and the nickel content of the residue is raised to be used as a nickel-removing raw material. Vanadium is precipitated by salt crystallisation, calcined to obtain V ₂ O ₅ , or refined into vanadium compounds for various uses (V, V ₂ O ₅ , NH ₄ VO ₃ , VOCl ₃ ).

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