At the end of the 19th century, there was an American female primary school teacher named Kelly Abbasser. Her husband was a mechanical repairman in a mine. One day, her husband brought back some chalcopyrite. She wanted her to clean the oily bag and use it for another purpose. She found that during the cleaning process, small particles of chalcopyrite could adhere to the soap bubbles and float on the water, while the soil sank into the bucket. Ultimately, this accidental discovery was the origin of the new technology of flotation and mineral processing.
More than a hundred years have passed, and flotation technology has been continuously improved and its applications have become more and more widespread. According to statistics, 90% of non-ferrous metal ores in the world are currently processed by flotation. In addition, flotation is also widely used. Used for sorting rare metals, precious metals, ferrous metals, non-metals, coal and other mineral raw materials.
In the modern flotation process, the application and precise addition of flotation reagents have become particularly important, because after treatment with flotation reagents, the flotability of minerals can be changed, so that the minerals to be floated can selectively attach to bubbles, thereby To achieve the purpose of mineral processing.
Development history of mineral processing agent addition system
Before the invention of logic circuits, the earliest flotation plants used manual addition of chemicals. Relying on the personal experience of the flotation workers, the opening of the chemical valve was manually adjusted to adjust the flow rate of the flotation chemicals.
In the 1960s, as motor technology matured, American water conservancy engineer Asses Andruos used the principle of a waterwheel to invent a scoop-type dosing machine. By changing the volume and number of scoops on the scoop plate, the amount of medicine added could be changed. flow.
But simply controlling the flow of flotation chemicals through rotation is far from enough. After the 1970s, transistor-embedded integrated circuit microcontrollers (Integrated Circuit) were transferred from the military industry to civilian use. Large-scale production reduced the cost to 1/100 of the past, Canadian Jack Johns, a car mechanic and electronics enthusiast, used his spare time to build the first logic circuit that can convert flow units into switching signals. At a technical exchange meeting, American Fisher (FISHER) Technical engineer Taland of the valve company learned about Jack Johns’ flow-switching technology and applied it to the field of valve control by acquiring the patented technology;
Nowadays, with the popularization of PLC programmable logic controller (representing the brand Siemens), people can quickly build a multi-point solenoid valve switching control system with only a little knowledge of automation logic programming. Such a system can now There are also many mining concentrators in use. Usually we call it: solenoid valve dosing machine (or gravity dosing machine).
In the mid-1980s, frequency conversion technology has been maturely applied in many industries. Using the frequency conversion principle to control mechanical diaphragm pumps can achieve higher precision pharmaceutical flow control than previous dosing systems (solenoid valve dosing machines and spoon dosing machines). This can help mine managers reduce chemical waste and management costs to a great extent.
After the 1980s, metering pumps began to shift to the industrial market, especially in the fields of precision chemicals and water treatment. Since the original design of metering pumps was to solve the problem of repeated and accurate delivery of standard fluids, metering pumps have been widely used in the mineral processing industry. , its shortcomings have also been exposed. The biggest problems are: 1. The controllable range of output flow accuracy is small. When a smaller amount is set, the error may be as high as 50% or more; 2. Diaphragm After rupture, the medicine will leak; 3. The flow rate is calculated entirely based on the linear relationship between the motor frequency and the pump head volume instead of the actual induced delivery flow rate. In the process of continuously adjusting the flow rate, the flow output error will increase. 4. Blockage of the pipeline will cause the pump head to burst under pressure, and the leaked chemicals will pollute the environment. 5. Flotation reagents with more impurities will cause the pump head check valve to become clogged and fail. 6. There are many external bypass control circuits and pipelines, making maintenance and installation more complicated.
Italian physicist Giovanni Battista Venturi discovered the Venturi effect using the Bernoulli fluid principle and then invented the Venturi tube. In 2013, Wilber applied the Venturi principle to the delivery of flotation reagents and invented the VLB The CNC dosing system (Patent No. ZL20140649261.1) uses circulating constant pressure water as the driving force to drive the diaphragm to add chemicals. The dosing system is controlled by a thick film logic control circuit. It was also called a hydrodynamic dosing machine.
Post time: Jul-30-2024
