White mud

Located in the west of Yuen Long District of Hong Kong, white mud faces the Deep Bay and overlooks Shekou, Shenzhen. It is said to be a good place for Hong Kong to watch the sunset. Along the coast are mud beaches, some of which are oyster fields, producing the famous "liufushan Oyster". The two main villages, shangbaini village and xiabaini village, are under the jurisdiction of Xiacun township.

White mud

This entry is compiled and applied by "popular science China" Science Encyclopedia

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White mud is a mixture, scientific name kaolin ore, belongs to non-metallic mineral. It can be used as paper coating, ceramic and filler.

brief introduction

White mud is a kind of non-metallic mineral. It is a kind of clay and clay rock mainly composed of kaolinite clay minerals. Because it is white and delicate, it is also called Baiyun soil. It got its name from Gaoling village, Jingdezhen, Jiangxi Province.

Its pure white mud is white, fine and soft, with good plasticity and fire resistance and other physical and chemical properties. Its mineral composition is mainly composed of kaolinite, halloysite, hydromica, illite, montmorillonite, quartz and feldspar. White mud is widely used in papermaking, ceramics and refractories, followed by coatings, rubber fillers, enamel glaze and white cement raw materials, and a small amount is used in plastic, paint, pigment, grinding wheel, pencil, daily cosmetics, soap, pesticide, medicine, textile, petroleum, chemical industry, building materials, national defense and other industrial sectors.

The raw ore price of Baini varies greatly. For example, the raw ore price of China Baini in Suzhou is 230 yuan / T, that of Fujian Longyan Baini company is 90 yuan / T, and that of Wuxian Qingshan Baini is 203.5 yuan / T. the raw ore price affects the selection of mining methods and technologies. Maoming white mud is a kind of sandy white mud. It is mainly produced by water mining and water transportation. There is no problem of raw ore sale. Its low-grade products are used for ceramics and fillers.

The mining methods of Baini mine include open pit mining and underground mining. Weathering residual type white mud mines are mostly open-pit mining, such as Maoming sandy white mud. Other hydrothermal alteration and sedimentary deposits are mined by surface mining in shallow part and underground mining in deep part.

There are many open-pit mining sites, but most of them are small and medium-sized mines. Large scale mines include Fujian Longyan Baini company, Guangdong Maoming Baini company and Guangdong Maoming Nanfang Baini company. Yangxi mining area and Yangdong mining area of former Suzhou China white mud company used open pit mining. Large scale underground mining are: Yangxi shaft, Guanshan shaft, baishanling mine in Yangdong and Qingshan Baini mine in Wuxian.

Composition

White mud minerals are composed of kaolinite cluster minerals such as kaolinite, dickite, perlite and halloysite, and the main mineral component is kaolinite.

The crystal chemical formula of kaolinite is 2SiO < sub2 < / sub ● al < sub2 < / Subo < sub3 < / sub ● 2H < sub2 < / Subo, and its theoretical chemical composition is 46.54% SiO < sub2 < / sub, 39.5% Al < sub2 < / Subo < sub3 < / sub, 13.96% h < sub2 < / subo. The albite minerals belong to 1:1 type layered silicate, and the crystal is mainly composed of silica tetrahedron and hydrogen oxygen octahedron. The silica tetrahedron is connected along the two-dimensional direction to form a hexagonal grid layer by sharing the vertex angle, and the non common peaked oxygen of each silica tetrahedron faces to one side. The peaked oxygen group of silica tetrahedron is shared by the silica tetrahedron layer and oxygen generating octahedron layer It becomes a 1:1 unit layer.

Genesis of the deposit

Kaolin is a common and very important clay mineral in nature. It is formed by the weathering of feldspar or other silicate minerals in igneous and metamorphic rocks in acidic media lacking alkali metals and alkaline earth metals.

Soil classification

The minerals contained in kaolin in nature are mainly divided into clay minerals and non clay minerals. Clay minerals mainly include kaolinite group minerals and a small amount of montmorillonite, mica and chlorite; non clay minerals mainly include feldspar, quartz and hydrate, some iron minerals such as hematite, siderite, limonite, titanium minerals such as rutile and organic matter such as plant fiber. Clay minerals are the main factors determining the properties of kaolin.

Cause classification

Based on the genetic basis of kaolin deposits, according to the differences of metallogenic geology, geographical conditions, deposit scale, ore body shape and occurrence characteristics, ore material composition and other aspects reflected by different mineralization, the kaolin deposits in China are divided into three types and six subtypes according to the code for geological exploration of Kaolin Deposits.

1. Weathering type: it can be divided into weathering residual subtype and weathering eluvial subtype;

2. Hydrothermal alteration type: it can be divided into hydrothermal alteration subtype and modern hot spring alteration subtype;

3. Sedimentary type: it can be divided into sedimentary and sedimentary weathering subtypes and kaolinite clay rock subtype in coal bearing strata.

Industrial type

According to its texture, plasticity and sandy content, it can be divided into three types

1. Hard kaolin: hard, no plasticity, with plasticity after grinding.

2. Soft kaolin: soft, strong plasticity, sandy content < 50%;

3. Sandy kaolin: soft, weak plasticity, sand content 50%.

comprehensive utilization

At present, a lot of work has been done on the comprehensive utilization of white mud at home and abroad, mainly including using white mud to produce ordinary portland cement, alkali residue brick, plastering mortar, using white mud to carry out flue gas desulfurization, producing calcium magnesium fertilizer or soil conditioner, rubber materials, alkali residue and padding materials, etc. In addition, in August 2005, Qingdao Soda Industry Co., Ltd. extracted a kind of bactericidal and health care product from white mud for fish and shrimp ponds. This product has been tested many times and the effect is obvious. At present, the technology has been put into use, and can consume 20000 tons of white mud every year. Although the amount of white mud treatment is limited, the process of white mud treatment is significantly accelerated, which is a new breakthrough in the comprehensive utilization of white mud.

Research progress

In papermaking industry, alkali recovery white mud is a by-product of pulping and papermaking process treated by alkali recovery technology. Its composition is similar to alkali recovery white mud, and its properties are very similar. At present, there are few researches on the production of precipitated calcium carbonate from white mud, so we can learn from the research on the preparation of calcium carbonate from white mud in papermaking industry.

At present, the whiteness of precipitated calcium carbonate is required to be greater than or equal to 90 degrees according to the industry standard, while it is required to be more than 92 degrees in some industries in the market, so whiteness is one of the important indexes of precipitated calcium carbonate. Hu Qingfu et al. Studied the whitening of precipitated calcium carbonate in 2002. The reason for the decrease of whiteness of white mud is that it contains ferrous metals such as iron and manganese, which exist in the form of Fe, Mn ions and oxides, so that white calcium carbonate is colored and whiteness decreases. It can be whitened by chemical method. The method is as follows: Taking Fe removal as an example, if in the process of digestion, carbonization or cooked slurry, reducing agent is added to make it react with Fe ion and its oxide, Fe is reduced to water-soluble Fe ion, and iron ion in white mud is removed by filtration to achieve iron removal and whitening. The added substances such as sodium bisulfite, calcium sulfite, sodium thiosulfate, sodium bisulfite and hydrazine hydrate are all strong reducing agents. In addition, by selecting different reducing agent, complexing agent, regulator and temperature for orthogonal test, the influence of reducing agent, complexing agent and regulator on the whiteness of light calcium carbonate was compared, and the appropriate amount of reducing agent, complexing agent and regulator and the optimal temperature under the optimal whitening effect were determined. However, when this method is used to whiten white mud, new impurities will be brought in, which may reduce the content of calcium carbonate in white mud and affect the quality of precipitated calcium carbonate products.

Address: Western Yuen Long, Hong Kong

Longitude: 113.948269

Latitude: 22.435004

Traffic information: minibus line 33: Yuen Long (Tai Fung Street) - ha Pak Nai

On holidays, there is another village bus nr941 to and from Yuen Long, with the same routes and charges as the light bus

Chinese PinYin : Bai Ni