Ordinary dry mix mortar production line have the advantage of excellent performance, extensive usage, stable quality, friendly environment, it gradually replaced the field mixed mortar. Dry mixed mortar can make full use of industrial waste, waste stone powder, waste residue and so on. It can not only reduce the cost of dry mix mortar, improve the performance of mortar, but also help to protect the environment, save resources, with good social and economic benefits as well as environmental benefits. There are many factors that affect the quality of dry mix mortar. By comparing the specific production situation of our company, this paper expounds the key points and matters needing attention of quality control of dry mix mortar from three aspects of raw materials, production technology and finished product control.

The main ingredient of cement dry mix mortar production line is ordinary Portland. We should pay attention to the water secretion and then do some adjustment, if we use the Portland blast furniture slag cement. It is strictly forbidden to use low quality high alkali content small pits cement. The hydration process of dry mix mortar is about 3 to 5 days. According to season, 4 hours in spring and autumn, 5 hours in summer, 3 hours in winter and eventually 4 hours. At present, in order to reduce production costs and seize the market at low prices, some enterprises often ignore the key points of cement quality control. Therefore, in the process of external wall plaster, there are poor cohesion, large-scale alkali reflux, empty drum and cracking and other problems, it has buried a lot of hidden quality hazards in the follow decoration and decoration construction. When selecting sand, such as sand particle size distribution, mud content and sand particle fineness, three important indexes should be strictly controlled. Sand grains should be hard, must not contain more than 4.75mm particles, mud content should be less than 3%. Choosing better medium sand, it is the best to control the fineness modulus at 2.3-2.6. In general, the cumulative sieve margin of the 0.6mm sieve is greater than the cumulative sieve allowance of the 70%,0.3mm sieve is greater than 98% for the accumulated sieve of the 85%-95%,0.15 sieve. At present, the development of river sand is limited, many enterprises have begun to seek alternative products, but can not be at a glance. River sand contains more impurities, such as mica, when the mica content is more than 1%, the dry mix mortar production line has a greater impact on the frost resistance and impermeability; sand dunes usually contain more dust and must be cleaned and dried before they can be used; It should be used carefully, because mountain sand contains more mud and organic impurities, some sand due to severe weathering, low particle strength; It should be forbidden to use sea sand, because it is often mixed with shell breakage, slices contain more salt, corrosive effect on steel bars, difficult to deal with; building recycled aggregate in the use should pay attention to its lime content, mud content can not be too much, crushing index, porosity, robustness, particle shape, particle size distribution should be strictly controlled. After effectively controlling the quality of sand, cement and other admixtures and additives in dry mixed mortar can be adjusted appropriately, which provides a reliable guarantee for reducing the production costs.
According to the requirements, the water content of mortar for dry mix mortar production line should below 0.5%. If the water content of mortar is too high, it is easy to agglomerate when storing for a long time, which affects the usage. In the dry mix mortar production process, the temperature should be quickly raised to the desired temperature, and by comparing the furnace mild smoke temperature to adjust the conveyor frequency of dry sand belt conveyor, so that the water content of sand increases, reduce the frequency. Therefore, the high water content of the sand should be broadcast for a period of time, the Frequency of the cold belt should be controlled at about 38, when the moisture content of wet sand is 5%~7%, the frequency of the cold belt to be controlled at about 5 per cent of the moisture content of wet sand is less, the frequency O f the cold belt to be controlled in about 42; Between 65%.