Third, mineral processing and processing (a) product quality standards Glass siliceous raw materials mainly require high silicon content, low iron and aluminum content, and a suitable particle size composition. In the building materials industry standard promulgated by the National Building Materials Bureau in 1994, the siliceous raw materials are classified into superior grades according to the silica content and five grades of first, second, third and fourth grades. Detailed technical specifications can be found in JC/T 529-94. (2) Glass siliceous raw material beneficiation processing method Quartzite silicon feedstock include glass, quartz sandstone, vein quartz, synthetic quartz silica sand processed and deposited from chert weathering natural quartz sand (i.e., silica sand). Silica represented by sandstone has a high silica content. The beneficiation process mainly involves crushing and grading, and various granular products suitable for industrial requirements are obtained. Natural silica sand often contains a large amount of soil and various impurities. The beneficiation is mainly graded desilting. Those with high iron and aluminum content need to use magnetic separation or flotation to remove impurities. Part of the better quality pulse quartz can be used instead of crystal material to produce quartz glass. This material sometimes needs to be purified by acid ore separation. (3) Glass siliceous raw material process 1. Sandstone crushing process Sandstone crushing process currently has the following main types: (1) Direct pulverization process. The process flow is: raw ore → strip sieve → ç ´ç¢Ž type crushing → sieving → cone crushing → sieving → multi-stage roll crushing → screening → product. (2) Calcination and pulverization process. The process flow is: raw ore → bottle kiln calcination → water cooling → coarse crushing → medium crushing → cage grinding → screening → product. (3) Self-grinding and pulverizing process. The process flow is: raw ore → strip sieve → self-grinding machine → air grading system → qualified product and ultra-fine powder (over-granular grade → cage-shaped mill → hexagonal sieve → final product). (4) Wet rod grinding magnetic separation process. This is a new process successfully researched and promoted during the “Seventh Five-Year Plan†period in China. The process flow is: raw ore → coarse crushing → medium crushing → screening → rod grinding → high frequency fine screening → hydraulic classification → magnetic separation and iron removal → product . 2. Natural silica sand beneficiation process (1) Rub the sludge process. The general process flow is: raw sand→mixing scrubbing→de-sludge de-sludge→hydraulic grading (or wet sieving)→product. (2) Flotation process. The process flow is: raw sand→mixing scrubbing→de-sludge→flotation→product. (iv) Glass siliceous material dressing practice 1. Leizhuang sandstone mine The quartz sandstone of the Leizhuang sandstone mine of Yaohua Glass Factory in Qinhuangdao is densely cemented, with hard ore, f=18, and wear index of 0.6204. The dry three-stage roll process and the bottle type kiln calcination process are used respectively. After the "seventh five-year plan", the first wet-process bar grinding production line with an annual processing capacity of 100,000 tons was built in China. The process flow is shown in Figure 4.20.5. The key equipment rod mill in this process is φ1 800mm×3 000mm peripheral discharge type. Quartz sand products are 99.1% SiO2, 0.06% Fe2O3, 0.37% Al2O3, 84.4% in 0.1-0.5mm, 11.3% in less than 0.1mm, and 3.6% in 0.5-0.6mm. 2. Fangshan Sandstone Mine Fangshan sandstone mine of Luoyang Glass Factory is a dense cemented sandstone. The current average grade of mining: SiO298.29%, Al2O30.59%, Fe2O30.11%. When the mine was first put into production, it used bottle kiln calcination, coarse crushing of jaw crusher , crushing of impact crusher, and multi-stage processing of cage grinding. In 1980, it built a dry self-grinding production line. In 1989, another three were built. The self-grinding production line, the process flow is shown in Figure 4.20.6. The self-grinding machine has a specification of φ4mm×1.4m, and the average production capacity of a single machine is 10～12.47t/h. The product particle size composition is 0.9-0.076mm, chemical composition: SiO299.10%, Al2O3 0.43%, Fe2O3 0.14%-0.18%. In addition, an ultrafine powder of less than 0.076 mm with a productivity of more than 25% cannot be used as a glass raw material. In order to solve the problem of dry self-grinding dust pollution and high ultra-fine powder content, the mine is currently undergoing wet bar grinding and beneficiation process modification of the production line, and the process flow is similar to that of Leizhuang sandstone mine. The results of semi-industrial tests show that the 20~0mm ore, after rod grinding, sieving, deliming, magnetic separation, classification, dehydration and other processes, produces quartz sand containing less than 0.07% Fe3O3, 0.63~0.10mm fraction yield 97%, the concentrate yield was 73.2%. 3. Dongshan Silice Sand Base of Dongshan Island, Fujian Province Dongshan Silica Base, located in Dongshan Island, Fujian Province, is one of the best quality large-scale natural silica sand mines currently developed in China. The original grade of SiO2 is 97.2%, Al2O3 is 1.42%, and Fe2O3 is 0.15%. The mineral processing process is shown in Figure 4.20.7. At present, the base handles 353,000 tons of raw sand annually, with an annual output of 300,000 tons of glass sand and 40,000 tons of sand. Glass sand grade; SiO2 ≥ 97.5%, Al2O3 ≤ 1.30%, Fe2O3 ≤ 0.10%, particle size 0.5 ~ 0.1mm content greater than 90%. Molding sand (size 70/140) SiO2 ≥ 96.0%, Al2O3 ≤ 2.0%, Fe2O3 ≤ 1.00%, CaO + MgO < 1.50%, mud content ≤ 0.30%. 4. Dalin Silica Sand Co., Ltd. Inner Mongolia Tongliao Dalin Silica Sand Co., Ltd. has more feldspar , cuttings and heavy minerals in addition to clay . The company's selected sand production line was originally designed and constructed according to the Japanese “fluorine-free†flotation process. In the production and commissioning, after appropriate modification, the “fluorine-free and acid-free†flotation process successfully developed in China was adopted. The production process is shown in Figure 4.20. .8. The production line can produce 30,000 tons of quartz sand for cast steel resin sand or float glass. The yield of quartz concentrate is more than 50%, SiO2>97%, Al2O3<1.5%, Fe2O3<0.15%. Falling Film Evaporator,Scraped Film Evaporator,Wiped Film Evaporator,Thin Film Evaporator Wuxi Dingfeng pressure vessel Co., Ltd , https://www.wuxidingfeng.com