Research On The Optimization Of Raw Material Mixture Of BF Based On The Cost Of Production

The raw material mixture structure is very important for reducing manufacturing cost and attaining maximum profits for the Iron and Steel enterprises. The proportion of the cost of raw materials in pig iron reaches nearly 70 percent. So it is an effective ways to decide a reliable raw materials mix reducing the cost of product. Based on this demand, a model of raw material mixture optimization for the cost of the pig iron was established to calculate the marginal contribution of all kinds of raw materials (focusing on the changes of iron raw materials). And it provides decision support for the enterprises to make a reasonable raw material mixture.A integrated mathematical model was established in accordance with the process of metallurgical production and it was composed of the process models and the raw materials distribution models. The process models include the sintering process model, the pelleting process model and the iron making process model. The raw materials distribute models include the concentrate ores distribution model, sinter and pellets distribution model. The dates transferred among the models were the weight of raw materials or product, compositions, the prices and the shadow price of compositions of raw materials.The special features of the production planning model are as follows: (1) The goal of the model was the cost of product, rather than that of the raw material or work in process, such as the cost of sinter, or the cost of pellets .(2) By making use of the fuzzy program, many important parameters were calibrated from the fuzzy process model and the compositions of raw materials in the period of optimization. Then the relations among the quantity (producing output or consumption of raw materials), the compositions (product output or consumption of raw materials) and the cost or profit were accurately formulated. (3) The marginal contribution of the raw materials was presented to the decision maker. This model doesn't calculate the optimal value, but the marginal contribution of the raw material. (What we got is the change of the product profits when the amount of raw materials has a unit change). Such a result is more suited to the needs of decision-making of the current raw materials mix. In addition, the model was solved in the range of reference value of the period of optimization, removing the error. So the result was more accurate.Following conclusions can be drawn from the above research: (1) the method of fuzzy linear programming is able to calibrate the efficiency parameters of the process of BF. It is more easy and precise than the method of linear regression analysis. (2) By using distribution matrix to describe the distribution net of sinter, pellet and concentrate, can change the nonlinear programming into linear programming. It provides a reliable basis for calculating the marginal contribution of materials mixture.