Production of glass–ceramics from heavy metal gypsum and pickling sludge

Abstract

The aim of this investigation was to propose a preparation method of glass-ceramics derived from heavy metal gypsum and pickling sludge, as well as stabilization of Pb, Zn, Cd, As, Hg, Cr and Ni heavy metals. The process consists of the following two stages: the desulfurization of heavy metal gypsum and the preparation of glass-ceramics. Heavy metal gypsum was desulfurized by excess glass powder at 1,473 K and formed calcium silicate and silicon dioxide as intermediate products. The intermediate products, pickling sludge and small amounts of CaO and MgO were used as major raw materials for preparing parent glass. Glass-ceramics was produced by conventional heating method, which included a nucleation stage (973 K, 2 h) and a crystallization stage (1,173 K, 1 h). The main crystalline phase of the obtained glass-ceramics is akermanite (Ca 2 MgSi 2 O 7 ). A high microhardness of 5.3 GPa and a bending strength of 206 MPa, as well as a water absorption lower than 0.13 % were obtained. The leaching of toxic elements in glass-ceramics was much lower than the Environmental Protection Agency 1311 method requirement.

Transformation and Detoxification of Typical Metallurgical Hazardous Waste into a Resource: A Review of the Development of Harmless Treatment and Utilization in China

“…The chemical composition of SSD from two enterprises is shown in The chemical composition of SSPS is shown in Table 6. In Table 6, the overall view is that the contents of CaO, Fe 2 O 3 , and CaF 2 are high, and the metal oxides Fe 2 O 3 , Cr 2 O 3 , and NiO are relatively high, which means that they are rich in recovery value [28][29][30][31][32]. In addition, the chemical composition of SSPS generated by different steel mills and processes varies greatly; for example, some steel mills have a high SiO 2 content in stainless steel pickling sludge, which also results in a high content in the subsequent recycling [33].…”

In-Line Co-Processing of Stainless Steel Pickling Sludge Using Argon Oxygen Decarburization Slag Bath: Behavior and Mechanism

“…Zhao et al [11] and Yang et al [12] prepared glass ceramics with pickling sludge as a doping material and then solidified Cr. Pan et al [13] and others used sludge and gypsum to prepare glass ceramics, first removing the sulfur in the mixture and then preparing glass ceramics. In the context of solidification and stabilization treatment, while a heightened level of safety performance is achieved, this approach results in the underutilization of Cr resources, coupled with the detrimental environmental impact due to the release of sulfur.…”

Thermodynamic Analysis on the Reduction Smelting of Stainless Steel Pickling Sludge

“…With the rapid development of stainless steel industry, the resource utilization of pickling sludge is one of the new problems. In view of this, researchers at home and abroad have carried out more research on stainless steel pickling sludge, mainly including preparing glass [16][17][18], adsorbent [19], as a raw material for cement [20], firing building ceramsite, or making bricks [21]. At present, several large-scale stainless steel production enterprises in China, such as Baosteel and Zhangpu, use the method of outsourcing to dispose of the pickling sludge.…”