Use of cement

In 1871, Japan began to build cement factories.

In 1877, the British Crampton invented the rotary furnace, and in 1885 by Lantham reform into a better rotary furnace.

In 1889, near Kaiping Coal Mine in Tangshan, Hebei Province, China, the Tangshan "fine soil" plant was set up to produce by shaft kiln. In 1906, on the basis of the plant, the Qixin Cement Company was established, with an annual output of 40,000 tons of cement.

In 1893, the Japanese duo Hideyuki Endo and Mitaka Uchi invented Portland cement that is not afraid of sea water.

In 1907, Biere, France, used alumina ore instead of clay, mixed limestone fired into cement. Because this cement contains a large amount of alumina, it is called "alumina cement".

In the 20th century, while improving the performance of Portland cement, people successfully developed a number of cement suitable for special construction projects, such as high-aluminum cement, special cement and so on. The world's cement varieties have developed to more than 100 kinds, and the annual output of cement is about 2 billion tons in 2007. In 1952, China formulated the first national unified standard, which determined that cement production should be based on the principle of multiple varieties and multiple labels, and changed Portland cement to silicate cement according to the main mineral composition it contains, and then changed to Portland cement.

In April 2023, scientists at Washington State University in the United States injected environmentally friendly biochar into ordinary cement and obtained a new type of carbon-negative environmentally friendly cement.

Cement pollution prevention standard

Cement industry carbon emissions are second only to the power industry, resource consumption and ecological damage problems prominent cement industry is about to usher in a new round of elimination tide.

The Ministry of Environmental Protection recently released the "Cement Industry Pollution Control Technical Policy" (draft for comment) and the "Cement Industry Pollution Control Best feasible technical Guidelines" (draft for comment). The message conveyed by the two documents is that the country will comprehensively reduce pollutant emissions in the cement industry through the tightening of pollution prevention and control technical standards, while resolving the problem of overcapacity in the cement industry; Both technical policies and technical guidelines should be mandatory.

According to the Chinese Academy of Environmental Sciences, the China Cement Association, the cement industry is a key polluting industry, its particulate matter emissions accounted for 20% to 30% of the national particulate matter emissions, sulfur dioxide emissions accounted for 5% to 6% of the national emissions, some shaft kiln production to add fluorite to reduce the burning heat consumption, but also caused fluorine pollution in the surrounding area.

The cement industry is the third largest coal user in China after electricity and steel, and the average burning heat consumption of cement clinker in China is 115 kg standard coal/ton, which is more than 10% higher than the international advanced level. There are about 4,000 cement production enterprises above designated size in China, and more than 1,500 new dry process cement production lines. The cement industry is second only to the power industry in terms of carbon dioxide emissions. Mine resource consumption and ecological damage of cement enterprises are also prominent problems.

Chinese Society of Environmental Sciences, Hefei Cement Research and Design Institute prepared the "cement industry pollution prevention and control best feasible technology Guide" (draft for comments) introduced that the preparation group in 2010 to 158 cement enterprises research, for each 5000 tons/day clinker new dry process cement production line, enterprises need to pay pollution charges of about 900,000 to 1 million yuan.

If the technical transformation and supervision are in place, the emission of particulate matter is reduced by 50%, and the nitrogen oxide is reduced by 25%, the sewage fee can be reduced by about 300,000 yuan per year, which is equivalent to a reduction of 0.15 million yuan per ton of cement, and the sewage fee can be reduced by 1.395 billion yuan in the next five years according to the national volume of 1.86 billion tons of cement. At the same time, the pollution of dust, sulfur dioxide and nitrogen dioxide is reduced, and the environmental and social benefits are huge.

If the cement industry can achieve a 30% feedstock/fuel substitution rate in the next five years, it can reduce carbon dioxide emissions by 280 million tons per year, while reducing the use of fossil fuels, resulting in cost savings of $372 billion, resulting in significant environmental and economic benefits.

Kong Xiangzhong, secretary-general of the China Cement Association, said that the cement industry has always been continuously accompanied by overcapacity in the process of technological innovation. The red token of the state's control of cement overcapacity has been constant, but major technological innovation, upgrading and development at each stage have made a decisive contribution to resolving the industry's overcapacity.