The technology and science of mining mineral resources in or from the earth's crust. Generally refers to a metal or non-metal mining deposits, further comprising a generalized mining coal mining and mineral processing and oil. Its essence is a selective collection and handling process of materials. The mining industry is an important raw material mining industry. For example, metal ore is the main raw material for the metallurgical industry. Non-metallic ores are chemical raw materials and building materials. Coal and petroleum are important energy sources. Most ore needs to be enriched in ore before it can be used as an industrial raw material. The basis of mining science and technology is the theory of rock fragmentation, loose material migration, fluid transport, mine rock mechanics and mining systems engineering. The latest achievements in mathematics, physics, mechanics, chemistry, geology, systems science, and electronic computers are needed. The mining industry will further improve its production capacity and equipment utilization rate by improving the design, shape, material, manufacturing process, inspection method and maintenance system of the fully mechanized mining equipment on the basis of the highly mechanized structure that has been basically achieved. At the same time, the mine will be automated and remotely controlled in many aspects such as lifting, transportation, drainage, ventilation, and gas monitoring. Both underground and open pit mines will implement centralized computerized automated management and monitoring. In some countries, robots have been tested on underground mining face to mine minerals that are more damaging to personnel. On the other hand, with the continuous exploitation of underground minerals by humans, the quality of mining is from high to low, resources are scarce, forcing the use of low-grade minerals, selecting appropriate mining and mineral processing methods, comprehensive mining and comprehensive utilization, and improving mineral resources. Utilization rate and recovery rate, reducing the loss rate and depletion rate of ore. The toxic gases, waste water, waste rock and dust generated during mining and beneficiation, as well as noise and vibration, have caused harm to the environment, land, atmosphere and water quality, and have always been a concern. Countries have further raised the issue of long-term use of resources in research on environmental issues, with a particular focus on waste slag, waste rock, reuse of waste liquid, and land reuse after destruction. Develop strong laws and take effective measures to ensure the mine environment. A brief history of primitive humans has been able to collect stones, polished into production tools, and collect clay for pottery, which is the earliest mining germination. Ancient Chinese mining has a long history, from Hubei Daye Copper Green Mountain unearthed ancient copper mine for mining, loading, lifting, drainage, lighting and other production tools and a variety of pottery, copper, iron, wood, bamboo, stone, and Copper ingots, copper weapons, etc., confirmed that the spring, autumn and autumn have used vertical wells, inclined wells, and alleys to jointly develop, and initially formed an underground mining system. By the Western Han Dynasty, the mining system was quite perfect. At this time, iron, copper, coal, gold and other mines in Hebei, Shandong, Hubei and other places have begun mining. At the end of the Warring States period, Qin Guozheng Tai Shou Li Bing drilled a salt well in the Shuangliu County of Sichuan Province today. Before the Ming Dynasty, there were mainly iron, copper, tin , lead , silver , gold, mercury and zinc . At the beginning of the 17th century, Europeans used China's incoming black powder for mining, and the use of rock blasting to replace manual excavation was a milestone in the development of mining technology. At the end of the 19th century and the beginning of the 20th century, mining explosives, detonators, detonating cords and rock drilling equipment were invented, forming a modern blasting technology; the use of electromechanical shovel, electric locomotive and electric power lifting, communication, drainage and other equipment formed a modern era. Shipping technology. Beginning in the first half of the 20th century, mining technology developed rapidly, and ammonium nitrate explosives appeared. Underground deep-hole blasting technology was used. Various mining equipments were continuously improved and enlarged, and mechanized mining processes suitable for different deposit conditions were gradually formed. A scientific method for mine design, deposit evaluation and mine plan management was proposed to develop mining from engineering to engineering science. After the 1950s, due to the use of new equipment such as down-the-hole drilling rigs , roller rigs , and self-drilling rigs , mining equipment was upgraded to large-scale, transportation and lifting equipment, and unmanned locomotives appeared. Electronic computer technology was used in mine production management, planning and design, and scientific computing. It began to use system science research mining problems and gave birth to system mining engineering. Mine production began to establish an automatic control system, using modern test equipment, testing technology and electronic computers to predict and solve some practical problems. Therefore, the mining engineering discipline was formally proposed and recognized. Characteristics The mining production environment and production process have the following characteristics compared with other industries: 1 The main raw material for mining and processing is the naturally occurring ore body. The mine site cannot be freely chosen, and the industrial reserves of the deposit cannot be imported or regenerated. Mine production capacity, service life and economic benefits are closely related. Each mine has to undergo a process of mine construction, production, normal production, production reduction and closure. 2 Mining equipment and personnel are often transferred with mining processes and processing objects, and there is no fixed processing plant. The mined ore body must be excavated into a series of roadways for mining preparation (acquisition) before it can start mining. The development, mining and mining work are coordinated with each other to ensure the normal production of the mine. Otherwise, it will cause loss of mining or mining, and force the mine to reduce production. 3 The general trend of mining work is that mining conditions are getting worse and worse, the grade of ore produced is gradually reduced, and the cost may increase. Due to the mixing of rocks, the ore is depleted and the quality is reduced. Some ore cannot be produced and lost to the ground. Therefore, we must continuously improve mining and mineral processing technologies and carry out comprehensive utilization to reduce costs. Reducing the rate of depletion and loss is an important quality management task in mining production and has great economic potential. 4 The ore body has complicated conditions and shapes, and the grade distribution is uneven. Industrial reserves may have large changes in the mining process, making mining design difficult to standardize. In addition, the mining period is long and the capital investment is large, so the investment risk is also large. 5 Mining work in open pit or underground mining. The labor volume is large, the working conditions are poor, the safety is poor, and it is difficult to achieve comprehensive mechanization and automation. Therefore, special attention should be paid to improving labor protection and environmental conditions. 6 The operational effect of a mine depends to a large extent on the market supply and demand and value of the ore being opened. Therefore, the evaluation of mine management level cannot be the same as other industries, and the absolute economic benefits are the standard. Mining methods can be broadly classified into three basic mining methods: open pit mining, underground mining, and liquid mining. 1 open pit mining. That is, under the open air conditions, the shallower ore will be mined and mined from the pit open pit mine, the hillside open pit mine or the stripped open pit mine. This includes digging a series of sequential grooves. Sand mining is also a type of stripping open pit mine that excavates from a punt. 2 underground mining. The ore will be buried deep, and the ore will be mined underground using natural support, artificial support and caving mining methods. 3 liquid mining. Also known as the special mining law. Extracting useful substances from natural brines, lakes, oceans or groundwater; dissolving useful minerals (or melting hot water), extracting the solution to the ground for extraction; using hot water flooding, gas flooding or burning The minerals are driven from one well hole to another well. Most liquid mining is done by drilling. For a specific deposit, select a reasonable mining method based on geological conditions and rock mechanics data. It would be desirable to have the mining method selected to achieve maximum economic benefits in accordance with production safety and proper mining of useful minerals. If the mining method is not properly selected, it will affect the mine production technical indicators and economic benefits for a long time.
Rice Cooker
A rice cooker or rice steamer is an automated kitchen appliance
designed to boil or steam rice. It consists of a heat source, a cooking bowl,
and a thermostat. The thermostat measures the temperature of the cooking bowl
and controls the heat. Complex rice cookers may have many more sensors and
other components, and may be multipurpose. Cooking rice has traditionally
required constant attention to ensure the rice was cooked properly, and not
burnt. Electric rice cookers automate the process by mechanically or
electronically controlling heat and timing, thus freeing up a heating element
on the cooking range that had to be otherwise occupied for rice cooking.
Although the rice cooker does not necessarily speed up the cooking process,
with an electric rice cooker the cook's involvement in cooking rice is reduced
to simply measuring the rice, preparing the rice properly and using the correct
amount of water. Once the rice cooker is set to cook, the rice will be cooked
with no further attention.
Features:
For modern home
rice cookers, the smallest single-person model cooks 1 rice cup (180 ml),
whereas large models can cook 10 cups. Commercial models can cook 20 or more
cups. As a possible source of confusion, model specifications and names may
list either cooked or uncooked capacity. Rice roughly doubles in size during
cooking; therefore, a 10 cup (uncooked) rice cooker can produce up to 20 cups
of cooked rice. The prices vary greatly, depending on the capacity, features,
materials used, and the country of origin.
The majority of
modern electric rice cookers are equipped with a stay-warm or keep-warm feature,
which keeps the rice at an optimal temperature for serving without over-cooking
it. Some gas cookers also have electric stay-warm mechanism. However, the
usefulness of this feature degrades over time, a microwave may be more energy
efficient or better suited to reheat rice that will sit longer than four hours.
Some rice
cookers use induction heating, with one or more induction heaters directly
warming the pot. This can improve energy efficiency.
Most modern
rice cookers use aluminium for the inner cooking bowl. There are some models
that use stainless steel instead of aluminium. Various other materials, such as
copper, pure carbon, ceramic, and diamond powder coating, may be used for
higher heat conductivity or better taste.
The
pressure-cooking models can raise the water's boiling point higher, e.g., from
100 °C at 1.0 atm up to about 110 °C at 1.4 atm, which speeds cooking. The
pressure-cooking models can also be used in high altitude areas, where the
boiling temperature is below 100 Celsius. Pressure cookers are also suitable
for cooking brown rice (which contains oils and bran fiber that cook
differently from pure white rice starch). Some pressure rice cookers have a
varying pressure control mechanism (named the "dual-pressure" method)
that creates repeated pressure/release cycles during the cooking.
There also
exist mechanisms to collect and return the boiled over liquid to the inner rice
bowl.
Many cookers now have microprocessor-controlled cooking cycles, which are often used to adjust for rice and
cooking type.
Applications
Rice cookers are typically used for the preparation of plain or
lightly seasoned rice. Each rice cooker model may be optimized to cook a
certain type of rice best. For example, most Japanese rice cookers are
optimized for cooking Japanese rice and may not be the best for other types of
rice[citation needed], although cooking time can be lengthened simply by more
water.
The typical method of cooking long grain rice
is boil-and-strain and/or steaming method. The absorption method used in
Japanese rice cookers will produce slightly different texture and taste,
usually stickier rice.
Brown rice generally needs longer cooking
times than white rice, unless it is broken or flourblasted (which perforates
the bran).
Different varieties of rice need different
cooking times, depending on their grain size, grain shape, and grain
composition. There are three main types of Asian rice: Oryza sativa subsp.
indica, i.e., Indian rice (long grain rice, e.g., basmati rice and Thai jasmine
rice), O. sativa subsp. javanica, i.e., Java rice (large grain rice) and O.
sativa subsp. japonica, i.e., Japanese rice (medium grain rice, e.g., Calrose
rice, short grain rice, e.g., most Japanese rice and risotto rice).
African rice, Oryza glaberrima, is an entirely
separate species, but can be cooked in the same way. Zizania is not even in the
same genus, although it is often called a rice (or "water oats"); it,
too, can also be cooked in a rice cooker.
A
rice cooker can be used to cook many boiled or steamed granular foods, such as
pot barley, bulgar wheat, and dal. Provided the ingredients have similar
cooking times, a rice cooker can cook mixtures such as khichdi. Some rice
cookers can be used as automated couscoussiers, cooking couscous and a stew
simultaneously.
Rice Cooker,Drum Rice Cooker,Deluxe Rice Cooker,Straight Rice Cooker Guangzhou Taipeng Electrical Appliances Technology CO., LTD. , https://www.taipengelectric.com
Mining basics