I. Current Status of Utilizing Waste Heat from Smelting Dry Slag

Currently, in the molybdenum-iron smelting process, for enterprises using dry slag discharge technology, the heat from the dry slag is essentially dissipated into the air and cannot be utilized. The initial temperature of dry slag is typically around 1700 Around ℃, 20 Minutes later, it will be downgraded to 800 Around ℃, 2 When I was young, it dropped to 400 Around ℃, due to rapid cooling and low temperatures, it qualifies as a substandard heat source. At the same time, the radiant heat from the dry slag creates a higher operating temperature for the slag-discharging personnel. Recovering thermal energy from molten dry slag falls under solid-state thermal energy recovery, a practice that is extremely rare—not only within the industry but even in other sectors as well.

We conducted an experiment at a domestic molybdenum-iron smelting enterprise to practically measure the heat generated by the smelting dry slag. The specific experimental data are as follows:

Experimental data show that one furnace of dry slag can transfer heat to produce 6,080.48 kg of hot water (equivalent to 95°C hot water) within one hour.

II. Project Feasibility Analysis

2.1 Economic Analysis

The thermal energy recovery system employs a single-stage heat exchange, based on experimental data and preliminary calculations. 18 Dry slag from furnace smelting can be converted into… 95 Assessing hot water quality 109 Ton, per ton of hot water 20 Based on preliminary calculations, the annual benefits would be: 109x20x330 Sky ≈ 72 Ten thousand yuan.

2.2 Reliability Analysis of Thermal Energy Recovery Projects

The thermal energy recovery project, due to its relatively low rate of return and complex operating conditions, avoided adopting aggressive, high-cost, high-tech, or immature processes during process design. When selecting equipment, priority was given to models with low failure rates and exceptional durability. As a result, the entire project features no easily damaged or vulnerable components, ensuring high equipment reliability.

III. Dry Slag Waste Heat Recovery Plan

The recovery of residual heat from metallurgical dry slag is divided into four main parts: the transportation section, the coil heat-exchange section, the insulation section, and the civil engineering section.

3.1  Dry slag disc transportation section;

The dry slag disc transport section uses mine car-style transportation, fabricated and installed based on the user's existing dry slag disc system. This transport component serves as the power system, driving the entire disc to move within the furnace body.

3.2  Coil Section

To fully utilize thermal radiation, denser coil tubes are employed to maximize the heat transfer area. While ensuring an adequate heat exchange surface, seamless welded pipes are used to minimize scaling issues that could otherwise impair performance. The heat exchanger tubes can hold water effectively. 6 Ton.

3.3  Insulation Section

Due to the significant temperature difference between the inlet and outlet sections, the upper part is insulated using fire-resistant cement combined with rock wool and aluminum-magnesium silicate, while the sides are insulated with steel structures layered over asbestos. The fire-resistant cement components are pre-fabricated off-site and then assembled on-site. In the high-temperature zones at the front of the insulation on both sides, a "first insulation, then thermal protection" approach is employed—meaning the insulation material must first provide effective waterproofing, while the thermal protection layer itself needs to withstand high temperatures and exhibit low water absorption.

3.4  Civil Engineering Section

The Civil Engineering Department adjusts according to the existing site conditions and adopts the optimal construction plan.