Discussion on the possibility of using container b

2022-08-26
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Discussion on the possibility of using container bags for cement (Part 1)

according to statistics, China's current annual output of cement packaging bags is about 8billion, and they are all disposable. The total tonnage of packaging waste will reach 1.6 million tons based on an average of 200 grams per piece. Due to the difficulty in recycling paper plastic composite bags, they are currently being studied and tried. Therefore, these large amounts of waste, not only caused a waste of resources, but also caused pollution to the environment that can not be ignored. The market calls for the joining of new cement packaging materials

in order to ensure the quality of cement more scientifically and effectively, and package cement more economically and reasonably, the relevant national departments have recently revised the national standard of cement packaging bags. It is reported that a regulatory standard for cement packaging may be introduced in the next few years. The "regulation" describes the effect of cement packaging, allowing the diversity of cement packaging

as a new type of packaging material with low cost, large capacity and suitable for rapid loading and unloading, container bags have a good development prospect for bulk cargo such as cement. Containerized cement is technically feasible, economically considerable, environmentally friendly and suitable for long-distance transportation. Therefore, it is of great practical significance to study and discuss the use of containerized bags in cement packaging

first, compared with ordinary small bags, container bags have better uniqueness in the protection of contents

cement, as one of the important building materials, has a great impact on the national economy and the people's livelihood. Therefore, it is very important that the quality of cement can be effectively maintained during the storage period, and the chemical properties of cement itself determine that it is vulnerable to the influence of the surrounding environment. This requires that the cement packaging should have the following basic properties, namely moisture-proof, breathable, heat-resistant and low bag breaking rate, which are also the basic elements in the container bag design

1. in order to prevent moisture, the container bag can be lined with either paper or coated woven cloth, or even PE wide film. The moisture-proof effect of these measures is obvious, and appropriate selection according to the product morphological characteristics and transportation routes can have a good effect. Container bags were once widely used in the export of relatively valuable products such as starch and diatomite. Facts have proved that these packages have withstood the test of shipping. In theory, we should be more confident about the moisture-proof treatment of the concept of "attracting projects with platforms" for cement products

2. The air permeability when the container bag is filled with cement can also be solved by puncturing the lining material, and due to technological factors, the disadvantages of small bag puncturing one side inward and one side outward can be avoided. The woven density of container bags is generally 56 × 56 wires/10cm to 60 × Between 60 wires/10cm, it is difficult for the moisture outside the bag to pass through the lining continuously, unless the external environment keeps a certain pressure on the bag. This situation is neither reasonable nor possible. If you need better exhaust performance and absolutely eliminate the danger of humidity, you can also consider the design of adding an exhaust device at the feeding port instead of puncturing the PE lining

at the same time, we note that inflatable filling is not the best choice for cement filling. Its characteristic is that the dust flying at the filling site is very unsanitary, which is easy to cause air pressure expansion; The advantage is that to a certain extent, it can reduce the temperature of the cement during inflation and reduce the damage to the packaging. Screw operation is convenient. The way of filling cement with screw propulsion machinery is quietly rising. Its pollution to the environment is greatly reduced and the filling efficiency is improved. However, when loading, the mode of feeding the heat collection pocket sideways can disperse the heat more evenly, and it has good heat resistance. Therefore, it can make up for the shortcomings of the two filling methods to a certain extent. Of course, if appropriate measures can be taken to control the cement temperature within a certain range, the filling effect will be better

3. The container bag has good heat resistance when it contains PE lining or other linings, and the continuous low heat of 60 ℃ ~ 80 ℃ will not damage the fabric. There are provisions on heat resistance in gb10454-89 flexible container bags. Years of practice has proved that the vast majority of containerized bag manufacturers and their products can basically meet this requirement

4. There is a different concept between the broken rate of container bags and that of cement bags. The six times dropping test of cement bags is to imitate the process of transportation and the number of loading and unloading. The container bags should be hoisted and unloaded by mechanization. At least the qualified container bags, but many foam granulator enterprises do not pay attention to environmental protection in their production experience, and they should be hoisted for 30 times, which is much higher than the handling times of cement sludge. The breakage rate of small cement bags refers to the proportion of the losses caused by filling and handling in the fixed batch of products. If the containerized bags are not damaged and unloaded due to external force, scraping, scratching and collision, they are unqualified and are not allowed in design and production. Even qualified containerized bags must pass the inspection of falling from 0.8m height without breaking the package. It can be seen that containerized bags are more reliable in preventing the loss of contents

II. There are considerable economic benefits in replacing small bags of cement with containerized bags

if the existing cement packaging bags are calculated as 200g/piece, 4kg of packaging materials are required for each ton of cement, while if the same ton of cement is packaged in containerized bags, only 2.5 ~ 3kg of packaging materials are required, saving 25 ~ 38% of materials. If calculated by 1.6 million tons of packaging materials, the country alone saves 40000 to 60000 tons of energy every year. Moreover, containerized bags also reduce the technical difficulty of recycling. Because it is different from the traditional adhesive of paper plastic composite bags, which sticks paper and woven bags together. If it is not firmly adhered during production, it is not qualified, and if it is firmly adhered, it is difficult to separate when it is recycled. Container bags are mainly made by stitching. When recycling, as long as it is cut into pieces and rinsed, it can be granulated to produce other products

for manufacturers, whether paper bags, composite bags or laminated plastic woven bags, as long as they are produced in strict accordance with the requirements of gb9774, the cost of small bags is generally between 1.5 and 2 yuan. If 20 packages are required per ton of cement, the packaging cost per ton of cement is 30 to 40 yuan. Of course, the above is only a budget estimate. The price of plastic products is affected by many factors, especially the price of container bags and the complexity of their production. We should carefully screen the design, formulate oneortwo processes according to the characteristics of our products, and determine the price. If you can save 1 yuan per ton of packaging, the annual savings from packaging will be considerable

it should be noted that some designed products in the container bag can be reused. In some projects, the cement consumption is large and the construction period is long. Containerized bags are likely to replace cement tankers in the transportation of such projects. In a short time (about 30 days), it is completely possible to use a cement container bag for three times. It can not only go farther than the cement tanker, but also because it has certain moisture-proof and even rain proof ability. Therefore, it can effectively maintain the quality of cement when stored outdoors for one to two months without special human maintenance. This is unmatched by the cement tanker, and the packaging cost saved directly here is also huge

(to be continued)

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