What are the ways to use waste marble?

In the process of mining, cutting and grinding, about 70% of marble is transformed into waste, resulting in a serious waste of resources and environmental pollution. The waste pulp produced by white marble contains calcium carbonate, and the waste pulp of colored marble contains iron oxide, magnesium, manganese, etc., in addition to calcium carbonate. Because no polluting admixtures are used when processing stone, marble waste can be regarded as a very pure mineral product, which can be ground into powder and used in industry and ecology.

The use of waste marble way one: the production of calcium carbonate

The main component of marble is calcium carbonate, and the waste is processed into powder by marble grinding machine, that is, calcium carbonate powder.

The use of waste marble two ways: the production of lime

Marble is a carbonate mineral, containing calcium oxide up to 50-60%, according to an average of 55%, burning loss of 40-45%, according to an average of 42%, more than 96% of calcium carbonate. After high temperature roasting, each processing 1000kg of dry base marble waste can produce 550kg of high-quality lime with calcium oxide content above 95%.

The use of waste marble three ways: as an aggregate for the preparation of self-compacting concrete

The use of limestone and marble waste aggregate of self-compacting concrete can be maximum permeability and filling. At the lowest water-binder ratio, the compressive strength of self-compacting concrete using marble waste aggregate is 6% lower than that using LS aggregate. Under the condition of low water-binder ratio, the use of marble aggregate instead of limestone in self-compacting concrete will not significantly reduce the strength.

The use of waste marble four ways: instead of limestone for calcination of Portland cement

Waste marble powder has high CaO content and low SiO2 content. From the perspective of chemical composition, waste marble powder is equivalent to higher-grade limestone ore. The high specific surface area of the waste marble powder is ultra-fine powder, which significantly increases the reactivity of the marble powder, thus offbalancing the high degree of crystallization, stable structure and low reaction ability of the waste marble powder. Therefore, the waste marble powder is the calcined Portland cement clinker of high quality calcined limestone raw material. By replacing natural limestone with 30% waste marble powder, Portland cement clinker with good quality can be calcined in the new dry process cement rotary kiln. The raw cement prepared with waste marble powder instead of limestone has an ideal calcining process in rotary kiln, which is characterized by low clinker firing loss and f-CaO, high 28d compressive strength, good burnability of raw material, stable thermal condition in kiln, and good adaptability of rotary kiln system to 30% waste marble powder instead of limestone.

The use of waste marble five: the production of artificial stone

Firstly, the marble waste is crushed, and then the marble powder is modified to improve the sintering activity of the marble powder. Silane coupling agent and titanate coupling agent are used in modification. Silane coupling agent is a kind of low molecular organosilicon compound, which acts as a bridge between inorganic phase and organic phase. Its general formula is RSiX3, where R represents the active functional group that has affinity or reaction ability with polymer molecules, and X represents the alkoxy group that can be hydrolyzed. In the coupling process, the active group on the marble surface is first adsorbed with the R group in the coupling agent, and then the X group connected with the silicon atom is hydrolyzed to generate silyl alcohol bond (Si-OH). The Si-OH on the surface of the marble powder particles reacts with each other and condensates into M-Si-O-SI-M covalent bond (M represents the surface of the marble powder particles). The film forming a network structure covers the surface of the marble powder particles, thereby improving the strength of the marble.

Although the stone processing waste is industrial solid waste, it has certain utilizability. Its long-term accumulation not only occupies land, but also causes pollution to the environment. Today, with the increasing requirements for environmental protection, it has become an important factor affecting the sustainable development of the stone industry. It is imperative to take technical measures to make resource utilization. In particular, the large-scale use of waste marble powder instead of natural limestone ingredients, the use of new dry process cement rotary kiln production of Portland cement clinker, can all absorb the marble powder waste discharged by the stone processing industry in the location and surrounding, is expected to completely solve the stone processing industry waste marble powder serious pollution of the local environment, restore the local ecosystem, waste into treasure, Promoting the sustainable development of stone processing industry has very significant social and economic benefits.