Air purification activities at non-ferrous metallurgy enterprises: goals and features

Manufacturer and supplier of gas-cleaning equipment PZGO LLC proposes to design, manufacture, deliver and install chemical scrubbers, absorption columns and adsorption towers for industrial air purification after galvanizing operations, as well as for other technological cycles associated with the production of copper, tungsten, titanium, lithium, mercury, magnesium, zinc, cobalt, aluminum and other colored, rare and rare earth metals.

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Harmful emissions from the nonferrous industry and methods for their neutralizing

In countries rich in polymetallic ores (Russia, US, Canada, Japan, Peru, Australia, Mexico), the volume of gross national income provided by non-ferrous metallurgy can reach 5-10%.

At the same time, this industrial branch consumes a truly huge amount of raw materials, and is also characterized by increased labor and energy costs. An important feature that characterizes this technical field is a significant release of harmful gases / aerosols / mechanical particulates.

The most energy-consuming productions are the lead, copper, nickel and cobalt industries.

The main technologies in obtaining pure colored metals are hydrometallurgy, pyrometallurgy and electrolytic method (galvanization). These and all other approaches to the extraction of metals from ores are closely related to toxic gaseous and gas-mechanical components, the neutralization of which is one of the key tasks of non-ferrous metallurgy.

Thermal, mechanical and chemical processing of raw materials / ores

Like in iron-and-steel industry, the first step in the production of non-ferrous metals is always mechanical grinding of ore. When crushing, a huge amount of dust is formed, often showing active chemical properties. Of course, such dust is a danger to both personnel and equipment, so it must be trapped on a mandatory basis.

Air scrubbers and wet chemical absorbers

Maximum efficiency in the treatment and sterilization of highly dusty streams is achieved by using wet fluidized bed scrubbers. The peculiarity of these devices lies in the compactness and simplicity of the design, which, nevertheless, makes it possible to score almost 100% sorption efficiency.

^{PP balls movement inside the working compartment of a FBS (this stand vividly demonstrates the process taking place inside the scrubber during the operation)}

The floating / movable bed is an array of polypropylene balls. The hollow thin-walled spheres, as a result of their chaotic movement, not only form a highly active fluidized bed, but also mechanically clean the interior of the working compartment of a machine.

Pyrometallurgical sector

Since scrubbers, to a greater extent, belong to the dust removal equipment, their use is very rational in pyrometallurgical enterprises.

Matte smelting, as well as roasting of ore and fire refining are accompanied by release of hot air streams contaminated with microdispersed metal and non-metallic dust / fine stone chippings.

^{Steel-bodied (with inner lining) fixed-bed absorption column for wet trapping fine dust and aggressive / toxic gaseous impurities connected to non-ferrous metallurgy. The apparatus is capable of productive handling high-temperature emissions}

Moisture scrubbers not only effectively capture dusts of any nature, but also significantly chill the hot stream down.

Fixed-bed absorption columns work on the nearly same principle, demonstrating an even higher degree of trapping of chemically active components. Perhaps the only drawback of absorption systems is the impossibility of treating gas-air flows that are heavily contaminated with mechanical impurities (ash, soot, and skull). Therefore, in case of noticeable presence of mechanical particles in the flow, a scrubber-type dust collector should be installed upstream of the absorber.

Hydrometallurgy

One of the large branches of metallurgy is hydrometallurgy. To date, about 20% of such metals as copper, aluminum, zinc, nickel, aurum, uranium, cobalt and cadmium are obtained by hydrometallurgic method.

The main technological procedures of hydrometallurgy are electrolysis and leaching of ore. Regardless of the specific method, highly active alkaline aerosols are formed as a by-product. Chemical neutralization equipment is required to deactivate alkaline emissions.

If the contaminated stream contains little or no mechanical impurities, then the best equipment for cleaning the gas phase are fixed-bed / packed absorbers, as well as bubbling / orifice / foam absorbers.

^{Packing (stailess-steel Pall rings) irrigation inside the working champer of a packed-bed horizontal absorber}

The main physical functor of absorbers (of barbotage, vertical and horizontal types) is a thin microfilm of liquid that is formed on the surface of special-topology bodies (Pall rings, Raschig rings, Levin’s bodies, Dixon rings) through the spraying of process water or chemical agent atop the packing layer.

Since leaching of ore is directly related to strong alkalis, neutralization is most efficiently carried out with acidic reagents.

As for hydrometallurgical electroplating, the conductive electrolytes can be not only alkalis, but also salt solutions, acids and even molten crystals.

Elaborate design, a variety of packings and reagents available for absorbers make it possible to neutralize / recover / transform almost any toxic or undesirable gaseous / aerosol / colloidal compounds.

Mercury production

Special attention should be paid to such non-ferrous metal as mercury (Hg). Despite the significant danger of mercury, it is widely used in medicine, engineering, electronics, metallurgy.

Today, elemental hydrargyrum is mainly obtained through the metallothermic method of roasting cinnabar (vermillion).

^{99-100% effective DeSOx adpsorption unit (produced at PZGO LLC)}

As is clear from the name of the method, the main process is the heating of mercury ore. After crushing the mercury-containing ore (HgS), the resulting rock flour is charged into a tube furnace. As a result of heating, sulfur combines with the oxygen of the air, turning into gaseous sulfur oxide. Mercury enters the liquid state of aggregation and condenses into droplets and being captured.

High selectivity and efficiency in the retention of pure sulfur dioxide is shown by adsorption columns filled with a dry adsorbent. Depending on the details of the process, activated carbon, silica gel or aluminum-containing highly porous materials can serve as a filler. Read more about dry adsorption towers.

Equipment engineering, manufacture, delivery and commissioning

To discuss the individual conditions regarding the design and manufacture of air-cleaning systems for non-ferrous metallurgy enterprises, please fill out the Customer’s questionnaire or contact us in any convenient way.

We are ready to carry out fast delivery of devices to any region of Europe and Asia and, if necessary, to put equipment into operation at your production site.

We guarantee high reliability, affordability and efficiency of all our devices.

PZGO LLC – breathe with ease!