The research addresses the issue of utilization of neutralized SPENT sulfuric acid PICKLING LIQUOR, deposited in 1.62 ha lagoons, derived from steel industry, in cement production. Physical–chemical characteristics of the investigated waste revealed low levels of contaminants with the exception of sulfate anions. However, the presence of CaSO4 2H2O revealed a new utilization option for the investigated waste. A key part of the research involved studying the usability of stored waste as a substitute of natural gypsum, acting as a set retarder in cement production. Cement was prepared by grinding Portland clinker with the addition of waste gypsum and then was subjected to the examinations of initial setting time, specific surface, water demand and compressive strength. The analysis of mechanical and physical properties revealed that the tested cement with the addition of waste meets standard requirements for Portland cement. Furthermore, the study of natural radioactivity of the waste did not reveal a rise in the level of radionuclides, thus confirming that the investigated waste can be used for the production of construction materials used in buildings intended for human residence. Utilization of the deposited wastes can help eliminate the environmental hazards regarding sulfuric acid pickle LIQUOR waste and can also provide a low-cost resource of waste gypsum, which can be widely used in the production of construction materials.

Improved alkali resistant refractoriness are needed for biomass and black LIQUOR gasification (BBLG). One particularly harsh application is linings for gasifiers used in the treatment of black LIQUOR (BL). Black LIQUOR is a water solution of the non-cellulose portion of the wood (mainly lignin) and the SPENT pulping chemicals (Na2CO3, K2C O3, and Na2S). Development of new refractory materials for the black LIQUOR gasification (BLG) application is a critical issue for implementation of this technology. FactSage@ thermodynamic software was used to analyze the phases present in BL smelt and to predict the interaction of BL smelt with different refractory compounds. The modeling included prediction of the phases formed under the operating conditions of high temperature black LIQUOR gasification (BLG) process. At the operating temperature of the BLG, Fact Sage@predicted that the water would evaporate from the BL and that the organic portion of BL would combust, leaving black LIQUOR smelt composed of sodium carbonate (70-75%), potassium carbonate (2-5%), and sodium sulfide (20-25%). Exposure of aluminosilicates to this smelt leads to significant corrosion due to formation of expansive phases with subsequent cracking and spalling. Oxides (ZrO2, Ce O2, La2O2, Y2 O2, Li2O, MgO and CaO) were determined to be resistant to black LIQUOR smelt but non-oxides (SiC and Si3N4) would oxidize and dissolve in the smelt. The other candidates such as MgAl2 O2 and BaAl2 O4 were resistant to sodium carbonate but not to potassium carbonate. LiAlO2 was stable with both sodium carbonate and potassium carbonate. Candidate materials selected on the basis of the thermodynamic calculations are being tested by sessile drop test for corrosion resistance to molten black LIQUOR smelt. Sessile drop testing has confirmed the thermodynamic predictions for Al2O3, CeO2, MgO and CaO. Sessile drop testing showed that the thermodynamic predictions were incorrect for Zr O2.

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 (Ca2MgSi2O7). 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.

Black LIQUORs are produced as a byproduct of chemical pulping and About 500 million tons of black LIQUOR are produced annually in pulp mills around the world, of which about 95% for fuel consumption and only 2% for the production of special products with higher added value are used. In order to recover more effectively, acidic precipitation of black LIQUOR using gas injection pretreatment has been studied recently. Previous studies have shown the advantage of carbon dioxide injection as pretreatment to reduce sulfuric acid consumption, increase yield and purity of lignin. The Iranian’ s pulp and paper mills have the potential to recover lignin, which is burned as fuel. Therefore, this study was performed to investigate new methods of lignin recovery on hardwood Kraft black LIQUOR in Iran. Pretreatment was done using carbon dioxide injection in lignoboost method as well as two-stage oxygen-carbon dioxide injection in Lignoforce method under 2 bar pressure and 80 ° C on Kraft black LIQUOR, Then, the pH was decreased to 2-3 using 6 M sulfuric acid to precipitate the lignin, which was then separated by filtration and washed with water. Finally, the recovered lignin was dried at 50º C. TGA, FTIR, SEM and AFM tests were performed to evaluate the thermal stability, chemical structure, morphology and dimensions of recovered lignin. Also, acid consumption, yield and ash content were calculated. The amount of acid consumed and the ash percentage of lignin recovered from gas injection processes was less than the non-injection method. In addition, the oxygen-carbon dioxide injection method showed higher efficiency compared to the carbon dioxide injection. FTIR results demonstrated a similar chemical structure in the recovered lignin. AFM and SEM images of lignin produced by pretreatment with carbon dioxide injection showed larger particles as well as higher thermal stability compared to oxygen-carbon dioxide injection.

Recently, it has been declared that fuel rods do not need to be anodized for the usage in VVER reactors. In this regard, some studies were planned to investigate the effects of PICKLING and anodizing treatments on corrosion behaviour of the fuel clads produced by Sooreh company. For this purpose, different surface treated samples of as-received, grinded, pickled, grinded and anodized, and pickled and anodized were prepared. The reference fuel clads in some equal conditions were also employed for comparisons. The results revealed that the corrosion behaviour is completely affected by the surface treatment, and microstructure properties have shown less impact. The oxidation type in the pickled, and pickled and anodized samples are absolutely different from the grinded samples. The anodizing treatment after PICKLING nearly increases the corrosion resistance by factor of two in comparison to the just pickled ones. The presence of grey oxide layer on the grinded samples are attributed to Monoclinic zirconia which has less corrosion resistance to Tetragonal zirconia.

Reducing production costs has become one of the most important concerns, due to the economic development and increasing competitiveness in industries. To achieve this goal, considering real conditions is important. In this presentation, we investigate the production scheduling of a PICKLING Line in Esfahan's Mobarakeh Steel Company called PICKLING Line Scheduling (PLS). The problem is to generate multiple production turns for the PICKLING Line coils and at the same time determine the sequence of these turns and select coils then the sequence coils of these turn so that the productivity and product quality both maximized while the production cost minimized. We formulate this problem as a mixed integer nonlinear program and propose a heuristic algorithm to obtain satisfactory solutions. Results on real production instances show heuristic algorithm is more effective and efficient with comparison to manual scheduling in Esfahan's Mobarakeh Steel Company.