Quartz sand is widely used in water treatment, new building materials and other chemical industries, quartz sand in addition to the main component silica, but also contains iron oxide, clay, mica and organic impurities, and natural quartz ore surface generally has a layer of hot metal formation film, relative to some of the iron content of the fine industry is strict requirements for the production of quartz sand must be pickling, To reduce the iron content in quartz sand. Pickling is mainly to eliminate quartz sand raw material quartz stone, diatomite carrier surface adsorption, reduce the chromatographic peak delamination carrier before production and processing need to be pickling treatment. Different kinds of quartz sand production process is very different, the following are to introduce the production process of refined quartz sand and acid washed quartz sand:
一、Quartz stone raw material quartz sand purification and pickling process
1. Use a certain concentration of hydrochloric acid solution to heat to a certain temperature, treatment 2-3 hours; The amount of hydrochloric acid is about 5% of the sand weight.
2. After the quartz sand is washed, at the same time, the concentrated hydrochloric acid and sulfuric acid (98%) are mixed, and placed at room temperature for 1-2 hours, or the mixture and quartz sand are stirred for a period of time to wash off the acid.
3. Treatment of acid and green alum: water, oxalic acid and green alum are mixed into a solution at a certain temperature in accordance with the proportion, quartz sand and the solution are mixed and stirred in accordance with a certain proportion, treated for a few minutes, the solution is filtered out and recycled after treatment, and the sand is cleaned, dehydrated and dried.
4. Hydrofluoric acid treatment: hydrofluoric acid treatment alone has the best effect, but requires a higher concentration. When shared with sodium disulfite, lower concentrations of hydrofluoric acid can be used.
5. Add a certain concentration of hydrochloric acid and fluorosilicic acid solution to the quartz sand slurry at the same time; It can also be treated with hydrochloric acid solution first, and then treated with fluorosilicic acid after washing. Or turn it upside down and process at high temperature for 2-3 hours, then filter and clean.
二、Second, the production process of refined quartz sand is common: dry method and wet method
Quartz sand produced by dry process can usually be divided into ordinary quartz sand, semi-refined quartz sand and refined quartz sand three grades. Because the surface of natural quartz stone is yellowish brown, the finished product that selects the smaller quartz ore material directly crushing and screening is called ordinary quartz sand, the surface is yellowish brown and white, its advantage is that the price is cheap, the disadvantage is that there are more impurities, so it is used in the construction industry; Select the larger quartz ore for processing is called semi-refined quartz sand, the surface is white, but dotted with yellowish brown spots, the product price is moderate, good quality, so the scope of application is wider. Select a large chunk of quartz ore, after artificial removal of the surface of the yellow brown skin and reprocessing is refined quartz sand, the surface is white, shiny like white sugar. Due to time-consuming processing materials, so the price is higher.
The main production equipment of wet quartz sand production line are jaw crusher, cone crusher (or fine jaw crusher, or impact crusher), quartz stone sand making machine, sand washing machine, dryer, etc. The process flow is roughly quartz stone after coarse crushing, fine crushing until sand, cleaning by the sand washing machine, drying by the dryer, and then sieve with vibrating screen, and then remove iron during the screening process. Wet process quartz sand can maximize the cleanliness of refined quartz sand, high taste, so the price is high!
三、There is only one common production process of acid-washed quartz sand: weak acid treatment
The production environment of acid-washed quartz sand is mostly in pure water or desalted water, which must first be treated with weak acid, and the reason why it needs to be treated with weak acid is that there will be no qualitative change in the water system because of the content of some substances in the water. The quality of quartz ore determines the concentration of hydrochloric acid and soaking time during pickling. The next is crushing, and now the quartz sand production equipment is one, and the ore comes out after entering the equipment. However, pickling quartz sand is not suitable for this equipment, because the ore can not directly enter the vibrating screen after crushing, but to enter the acid pool, so it is not suitable for integrated equipment. The concentration of hydrochloric acid is generally about 30%, and the immersion time is best for about 24 hours. After soaking, the quartz sand has no impurities, and the color becomes crystal clear and white, and finally, screening and washing, screening and washing in a set of equipment is completed at a time. The quartz sand thus produced is optimal for use in reverse osmosis and desalted water equipment.
Compared with pickling quartz sand, purified quartz sand needs to be calcined at 900 degrees, and then water quenching can produce tiny cracks inside for pickling, grinding with ball mill or Raymond mill, and finally pickling with hydrochloric acid, hydrofluoric acid, sulfuric acid with liquid, soaking and stirring for 24 hours can achieve the purpose of pickling.
