Question about precious metal content and non-ferrous metals in household appliances often arises among those who recycle electronics or want to understand the real cost of a used unit. The refrigeration compressor is the heart of the refrigeration system and is of greatest interest to processors due to its high concentration of copper, aluminum and quality steel. However, in order to accurately determine how much metal can be obtained, it is necessary to take into account the type of device, its power and year of manufacture.
The average weight of one compressor varies from 8 to 12 kilograms, but the yield of pure non-ferrous metal is only a part of this mass. A significant share is occupied by heavy housing, oil and refrigerant, which are of no value for non-ferrous metallurgy. Understanding the internal design will help you avoid mistakes when estimating the amount of scrap and correctly plan the dismantling process.
It is worth immediately noting that the numbers can vary significantly depending on the manufacturer and model of the device. Modern piston units, which are most common in household refrigerators, have a standard structure, which makes it possible to approximately calculate the yield of useful raw materials. Below we will analyze in detail what this unit consists of and how much resources you can count on.
Design features and total weight
A hermetic compressor is a steel cylinder, inside of which a complex mechanical system is hidden. The outer casing, which you see from the outside, is made of sheet steel about 1 millimeter thick and serves as an oil reservoir and noise protection. It is this casing that makes up the bulk of the device, but its value as ferrous scrap is significantly lower than the cost of the internal components.
Inside the steel shell there is an electric motor and a compression group itself. Electric motor responsible for the rotation of the shaft, and the crank mechanism converts the rotational motion into translational motion, pumping up the refrigerant pressure. This entire structure is immersed in oil, which lubricates the rubbing parts and removes heat. The weight of the entire assembly is usually about 10 kg, but the “useful” metal is distributed unevenly.
Many people mistakenly believe that the entire unit is filled with copper, but this is not the case. Copper is used primarily in motor windings, while the mechanical parts are often made of cast iron or steel. Aluminum is found in some models of pistons or in heat exchangers if they are integrated into the housing, but more often this is the province of larger industrial installations.
⚠️ Attention: Inside the compressor there is compressor oil, which is a hazardous waste. When opening the case, it may leak, so prepare a container for collecting liquid and a rag in advance. Do not pour oil down the drain or onto the ground.
To accurately understand what is inside, it is important to know the structure of the unit. The main elements include:
- 🔌 Stator and rotor —the electrical part of the engine, containing the bulk of copper.
- ⚙️ Crank mechanism —the mechanical part, made of steel and cast iron.
- 🛢️ Oil system —channels and reservoirs for lubricating rubbing steam.
- 🔩 Valve group —thin steel plates that ensure the movement of freon.
Copper content in motor windings
The most valuable component of the compressor is copper. It is used to wind the stator coils of an electric motor. The amount of copper directly depends on the power of the motor and its efficiency. In old Soviet-made models or units of the last century, the winding could be made of aluminum, which significantly reduced their cost for scrap, but modern standards require the use of electrolytic copper.
The weight of the copper winding in an average household compressor ranges from 1.0 to 1.5 kilograms. This is a pure metal that is highly valued at non-ferrous metals collection points. To extract copper, it is necessary to completely disassemble the electrical part by cutting off the body with a grinder and removing the core. This process is labor-intensive and requires skills in working with power tools.
It is important to note that in some budget models, manufacturers can use windings containing impurities or even bimetallic wire, where only the outer layer is covered with copper. This can be determined by the color of the wire cut: pure copper has a uniform reddish-orange tint, while copper-bonded aluminum the cut will be silver.
In addition to windings, copper can be found in supply tubes if they have not been replaced by steel by the manufacturer. In older refrigerators, the tubes were often made of pure metal, which added another 200-300 grams to the total output. However, new models (after 2000) commonly use copper-plated steel or all-steel lines.
Aluminum and other non-ferrous metals
Unlike copper, the aluminum content in a standard refrigerator piston compressor is minimal or non-existent. This light metal found its main application in the piston group of some models, where the requirements for the weight of reciprocating masses are critical. However, more often, pistons are made of duralumin or special alloys, which, when scrapped, are classified as “aluminum alloy” rather than pure aluminum.
Sometimes aluminum elements can be found in heat exchangers built into the compressor housing to cool the oil, but this is rare for household appliances. The bulk of aluminum in a refrigerator is found in the evaporator and condenser (radiators), and not in the compressor itself. If your goal is to collect non-ferrous metal, then radiators will provide a much higher yield of this metal.
Other non-ferrous metals, such as brass or bronze, can be found in the form of bushings, plain bearings or valve plates. Their quantity is calculated in grams, so collecting them separately is not economically feasible. Usually they remain in the total mass of ferrous metals or are melted together with other components.
For clarity, consider the approximate distribution of metals in a typical compressor:
| Component | Material | Approximate weight (kg) | Liquidity |
|---|---|---|---|
| Motor winding | Copper | 1.0 - 1.5 | High |
| Case | Steel | 6.0 - 8.0 | Low |
| Mechanism (shaft, connecting rod) | Steel/Cast Iron | 2.0 - 3.0 | Low |
| Piston | Aluminum alloy | 0.2 - 0.4 | Average |
Why is pure aluminum rarely used in compressors?
Pure aluminum has low wear resistance and a high tendency to scuffing during friction. In compressor friction units, where pressures reach tens of atmospheres, special alloys or steel are needed, so pure aluminum is practically not found there.
Ferrous metals: steel and cast iron
The main mass of the compressor, as already mentioned, is made up of ferrous metals. The body is made from cold-rolled steel, which has good magnetic properties and strength. This is necessary in order to withstand the high pressure inside the system and the vibrations of a running engine. The weight of the steel casing can reach 8 kg in powerful models.
The internal mechanics - shaft, connecting rod, cylinder body - are often made of cast iron or high-strength alloy steel. These materials provide the necessary structural rigidity and durability. When sold for scrap metal, these parts are classified as dimensional steel or "heavy scrap", the price of which is much lower than for non-ferrous metals.
Do not forget about fasteners. Bolts, studs, fastening plates are made of steel. Although their weight is small (about 200-300 grams), when processing large quantities of equipment, their total mass becomes noticeable. There is no point in separating them on purpose; they go into the general pile of black scrap.
⚠️ Attention: Material characteristics may vary depending on the manufacturer and year of manufacture. Some modern compressors may have composite elements or a modified piston design. Always check the technical documentation of a specific model if you need accurate data for engineering calculations.
Metal extraction technology
The process of cutting a compressor to obtain metal requires compliance with safety precautions and the availability of a certain set of tools. Simple disassembly with a wrench is not enough here, since the device body is hermetically sealed. To access the insides, you must use an angle grinder (grinder) with a metal disc.
The first step is always to remove the refrigerant. Even if the refrigerator is old, there may be residual pressure of gases in the system, which, if heated or damaged, can be dangerous. It is recommended to drill a copper tube with a thin drill away from the cutting area to bleed off any remaining gas.
The following is the sequence of actions:
- 🔧 Cut off the top housing cover with a grinder in a circle.
- 💧 Drain the compressor oil into the prepared container.
- ⚡ Cut out the electric motor along with the core.
- 🔨 Separate the copper windings from the steel set of plates (this can be done by breaking one side of the core and knocking out the copper).
- 🧹 Clean the copper from varnish and insulation (optional, to increase prices).
☑️ Checklist for cutting the compressor
When working with an angle grinder, be sure to use safety glasses and gloves. Steel shavings and sparks can injure your eyes, and sharp edges of cut metal can injure your hands. It is best to work outdoors or in a well-ventilated area, since when old winding insulation burns, caustic smoke is released.
Economic feasibility and conclusions
Is it worth disassembling the compressor for the sake of metal? The answer depends on your goals and scope. If you have one old refrigerator, then the cost of the grinder disc and the time spent may not be worth the cost of the resulting copper (approximately 1-1.5 kg). However, if you are engaged in recycling equipment professionally or have accumulated a dozen units, then the extraction of non-ferrous metal becomes a completely profitable activity.
In addition, handing over separated non-ferrous metal (separately copper, separately aluminum, separately ferrous metal) is always more profitable than handing over a whole compressor as mixed scrap. Reception points often lower the price for unassembled components, since they do not know exactly the contents and assume the presence of a large amount of dirt and oil.
In conclusion, we can say that a refrigerator compressor is a concentrate of useful materials, but access to them requires effort. The main value is the copper winding, followed by the aluminum alloy of the piston group, and the steel “shell” serves only as a transport container for these values.
Often asked questions (FAQ)
Approximately how many kg of copper can be obtained from one compressor?
On average, from 1.0 to 1.5 kg of pure copper can be extracted from one standard household compressor. In powerful models of two-chamber refrigerators, the output can reach 1.8 kg, in low-power ones it can drop to 0.8 kg.
Is there gold or silver in the compressor?
In ordinary household refrigerator compressors, precious metals (gold, silver, platinum) are not used. They can be found in microscopic quantities in the contacts of the starter relay, but their extraction at home is impossible and economically pointless.
Is it possible to hand over the entire compressor without disassembling it?
Yes, it is possible. Scrap metal collection points accept entire compressors, but classify them as “scrap of assembled electric motors” or “mix”, the price for which is much lower than for copper and aluminum sold separately.
What is the danger of a compressor when disassembling?
Main dangers: residual pressure of the refrigerant (risk of splashing oil and gas), sharp edges of the metal after cutting, the risk of poisoning by combustion products of the insulation during heating and the possibility of injury from a flying angle grinder disk if it hits hard parts of the mechanism.
What is the weight of an empty compressor housing?
The weight of a steel housing (casing) without internals is approximately 2-3 kg, depending on the thickness of the metal and model sizes. The bulk falls on the internal components: the engine and mechanics.