降低高硅铝土矿拜耳法生产氧化铝碱耗的研究

拜耳法生产氧化铝工艺是我国当前最主要的生产方法，该方法适宜处理相对高品位的铝土矿，随着高品位的铝土矿逐年减少，矿石品位日趋下降，导致各种消耗增加，本文通过对低A／S铝土矿的实际生产数据进行研究，找出最佳的控制方法，有效降低拜耳法生产氧化铝的碱耗。     

铝土矿成分对拜耳法氧化铝生产的影响

随着高品位铝土矿储量日渐减少，供矿品位不得不下降，结果引起产量减少，碱耗和矿耗指标明显升高，导致成本升高。因此，需要合理选择供矿品位，深入研究不同铝土矿的性质特点及杂质对氧化铝生产的影响，最大程度地发挥不同品位铝土矿生产氧化铝的效益，有效利用有限的铝土矿资源，成为氧化铝生产企业的迫切任务。     

刍议如何降低氧化铝生产低压蒸汽消耗及优化途径

蒸汽消耗量进行氧化铝生产的主要工艺指标之一,在氧化铝的生产成本中占有很大的比重,密切关系着氧化铝生产企业的经济效益。本文在此背景下,结合实际的生产作业情况,分析了降低氧化铝生产过程中蒸汽消耗的途径与办法,仅供相关人士参考。     

煤矿辅助材料生产企业成本降低途径的分析

现代市场竞争的日益激烈使得企业在追求利润最大化的过程中对成本控制的认识逐渐加深。如何在现代企业经营过程中降低产品成本成为了企业赢得市场占有率、提高企业市场竞争力的关键。本文就降低产品成本的途径进行了简要的论述。     

降低建筑工程造价的途径

按我国现行的建筑工程造价构成分析,占最大比例的是建筑安装工程费。而建筑安装工程费的多少取决于设计阶段,取决于设计时应用科学技术的含量。设计部门和设计人员要严格遵守"经济、适用、合理"的原则,精心设计,选择合理的设计方案,应用现代科技成果,是可以实现降低工程造价取得经济效果的目的。一般的民用建筑物由基础、墙体、柱、楼层及地层、楼梯、屋盖、门窗等基本构件组成。在设计中若能精心设计每一构件,在多个可行的方案中进行经济比较,使各个构件的造价降下来,则整个工程造价就会降下来。     

拜耳法生产氧化铝低压蒸汽综合节能探讨

本文从生产实际出发，通过对生产过程使用低压蒸汽进行剖析，找出影响氧化铝生产低压蒸汽的因素，提出解决低压蒸汽综合利用的方案，并按照方案对生产流程进行改造。通过改造前后技术参数进行对比，为今后工业生产控制提供参考。     

拜耳法氧化铝生产中草酸钠的再利用

文章通过对拜耳法生产氧化铝过程中草酸钠产生过程,及其草酸钠对生产的危害解析,在试验的基础上提出生产中产生的草酸钠回收再利用的最佳条件,最终指导实际生产。     

企业降低产品成本途径分析

降低产品成本对企业发展至关重要,降低生产中的各种消耗,合理利用机器设备、实施人本管理、提高产品质量、用系统整合的思想指导价格竞争、强化资金管理等是降低企业产品成本的重要途径。本文对企业如何降低产品成本的途径进行分析,供大家参考。     

降低施工项目成本的途径和措施

随着国民经济的发展，国家加大了对基础建设的投入，各地的建设项目也在大力的发展，采取有效的措施进行成本的控制是一个值得所有人思考的问题，本文主要从增收的角度和节支的角度分别论述了施工项目成本控制的方法和措施。     

廉价、低品位硅可使太阳能电池成本降低

加里弗尼亚大学伯克利分校开发出一个使低品位硅中缺陷减少的新工艺，此项成果可使太阳能电池成本降低。目前，全世界近90％的太阳能电池是用与集成电路使用的高纯硅相同的材料制造的。大量的、廉价的低级硅，由于含有许多杂质和缺陷，而不适于制造太阳能电池。提纯工艺成本昂贵，低级硅虽然便宜却又不适应用。     

Setup adjustment for discrete-part manufacturing processes with asymmetric cost functions

This paper presents a feedback adjustment rule for discrete-part manufacturing processes that experience errors at the setup operation which are not directly observable due to part-to-part variability and measurement error. In contrast to previous work on setup adjustment, the off-target cost function of the process is not symmetric around its target. Two asymmetric cost functions—constant and quadratic functions—are considered in this paper. By introducing a bias term in the feedback adjustment rule, the process quality characteristic converges to the optimal steady-state target from the lower cost side of the cost function. This minimizes the off-target loss incurred during the transient phase of adjustment. A machining application is used to illustrate the proposed adjustment procedure and to demonstrate the savings generated by the proposed feedback adjustment rule compared to an adjustment rule due to Grubbs and to an integral controller. It is shown that the advantage of the proposed rule is significant when the cost of the items is high, items are produced in small lot sizes and the asymmetry of the cost function is large.     

Impacts of RFID implementation on cost structure in networked manufacturing

Radio frequency identification (RFID) presents the key innovative solution to automatically capture and track the movement of material items throughout an entire supply chain. In this article, we explore influences of RFID technology implementation on cost and profit efficiencies. For this purpose a mathematical model of supply chain cost structure and functions was created to analyse the impacts. The model, which has also been verified through a case study approach, is aimed to examine the economical impact of RFID implementation at an automotive original equipment manufacturer and its suppliers. To analyse the impact of the traceability system using RFID technology, a cost reduction parameter will be used. Since in automotive supply chains the functional dependence of individual parts is changing in the upstream and downstream supply chain, only certain parts will be calculated with their complete functions and relations.     

Lean manufacturing tool in engineer-to-order environment: Project cost deployment

The present paper proposes a modified version of the Manufacturing cost deployment (MCD) method to analyse engineer-to-order (ETO) production systems. The novel approach, named Project cost deployment (PCD), introduces two substantial and innovative modifications. To begin with, the concept of manual assembly macro-activity replaces the traditional concept of station. Then, a brand-new structure for classifying and analysing losses is introduced, that is specifically defined to deal with the inefficiencies of the manual assembly tasks. The validity of the approach is proved by a real-world industrial application. The obtained results demonstrate that the PCD method allows the analyst to identify the hidden losses and to quantify the wastes from an economical point of view. In addition, PCD permits to estimate the impacts of potential (lean) improvement activities and projects in terms of both efficiency and effectiveness.     

Informing additive manufacturing technology adoption: total cost and the impact of capacity utilisation

Informing Additive Manufacturing (AM) technology adoption decisions, this paper investigates the relationship between build volume capacity utilisation and efficient technology operation in an inter-process comparison of the costs of manufacturing a complex component used in the packaging industry. Confronting the reported costs of a conventional machining and welding pathway with an estimator of the costs incurred through an AM route utilising Direct Metal Laser Sintering (DMLS), we weave together four aspects: optimised capacity utilisation, ancillary process steps, the effect of build failure and design adaptation. Recognising that AM users can fill unused machine capacity with other, potentially unrelated, geometries, we posit a characteristic of ‘fungible’ build capacity. This aspect is integrated in the cost estimation framework through computational build volume packing, drawing on a basket of sample geometries. We show that the unit cost in mixed builds at full capacity is lower than in builds limited to a single type of geometry; in our study, this results in a mean unit cost overstatement of 157%. The estimated manufacturing cost savings from AM adoption range from 36 to 46%. Additionally, we indicate that operating cost savings resulting from design adaptation are likely to far outweigh the manufacturing cost advantage.     

Recovery of alumina and alkali in Bayer red mud by the formation of andradite-grossular hydrogarnet in hydrothermal process

Bayer red mud (RM) is an alumina refinery waste product rich in aluminum oxides and alkalis which are present primarily in the form of sodium hydro-aluminosilicate desilication product (DSP). A hydrothermal process was employed to recover alumina and alkali from "Fe-rich" and "Fe-lean" RM, the two representative species of RM produced in China. The hydrothermal process objective phase is andradite-grossular hydrogarnet characterized by the isomorphic substitution of Al and Fe. Batch experiments were used to evaluate the main factors influencing the recovery process, namely reaction temperature, caustic ratio (molar ratio of Na(2)O to Al(2)O(3) in sodium solution), sodium concentration and residence time. The results revealed that the Na(2)O content of 0.5 wt% and A/S of 0.3 (mass ratio of Al(2)O(3) to SiO(2)) in leached residue could be achieved with Fe-rich RM under optimal conditions. However, the hydrothermal treatment of Fe-lean RM proved less successful unless the reaction system was enriched with iron. Subsequent experiments examined the effects of the ferric compound's content and type on the substitution ratio.     

Rescheduling with controllable processing times for number of disrupted jobs and manufacturing cost objectives

We consider a machine rescheduling problem that arises when a disruption such as machine breakdown occurs to a given schedule. Machine unavailability due to a breakdown requires repairing the schedule as the original schedule becomes infeasible. When repairing a disrupted schedule a desirable goal is to complete each disrupted job on time, i.e. not later than the planned completion time in the original schedule. We consider the case where processing times of jobs are controllable and compressing the processing time of a job requires extra processing cost. Usually, there exists a nonlinear relation between the processing time and manufacturing cost. We solve a bicriteria rescheduling problem that trades off the number of on-time jobs and manufacturing cost objectives. We give a mixed-integer second-order cone programming formulation for the problem. We develop a heuristic search algorithm to generate efficient solutions for the problem. Heuristic algorithm searches solution space by moving and swapping jobs among machines. We develop cost change estimates for job moves and swaps so that the heuristic implements only promising moves and hence generates a set of efficient solutions in reasonably short CPU times.     

Use of the manufacturing system design decomposition for comparative analysis and effective design of production systems

The focus of this paper is on the use of the Manufacturing System Design Decomposition (MSDD) to make effective cost and production system design decisions. A comparative study is conducted to illustrate how and why the total cost is reduced when the functional requirements defined by the MSDD are achieved. The ultimate goal of this research was to advance manufacturing and production system development to being guided by engineering science and design rather than the common practice of duplicating another person’s or entity’s notion of the best physical implementation.     

Possibilities to reduce pavement rehabilitation cost of a collision-free road investment using an LCCA design procedure

In the past decades, many single carriageway roads in Sweden have been converted to collision-free roads as a cost-effective alternative to conventional motorways. Investigations have concluded that the road type has been successful in reducing the number of fatal accidents, despite increased operation and maintenance costs. In recent years, the focus has shifted to converting narrower roads, which are anticipated to further increase pavement rehabilitation cost but also complicate traffic management during road works. This paper first examines the consequences in terms of road agency and road user costs; second, the possibilities to influence future costs by design alternatives. A life cycle cost analysis was employed to study future costs. The analysis indicated significant increase in life cycle cost compared to a single carriageway road. The analysis of design alternatives also indicated that future agency and road user cost can be substantially improved by finding an optimal alternative.     

Additive manufacturing alumina components with lattice structures by digital light processing technique

Digital light processing technique was applied to manufacture alumina ceramic parts with two types of lattice structure units, i.e. vertex interconnect structure and edge structure. The internal porosity of the unit is 40%. The printed parts were sintered and the grain size is about 1.1 μm. The bending strength of the vertex interconnect structure is much larger than that of the edge structure. Materials genome initiative(MGI) aims to digital design and intelligent manufacture for advanced components. This research shows us an example to achieve this goal.     

A multiobjective topology optimization approach for cost and time minimization in additive manufacturing

The ever-present drive for increasingly high-performance designs realized on shorter timelines has fostered the need for computational design generation tools such as topology optimization. However, topology optimization has always posed the challenge of generating difficult, if not impossible to manufacture designs. The recent proliferation of additive manufacturing technologies provides a solution to this challenge. The integration of these technologies undoubtedly has the potential for significant impact in the world of mechanical design and engineering. This work presents a new methodology which mathematically considers additive manufacturing cost and build time alongside the structural performance of a component during the topology optimization procedure. Two geometric factors, namely, the surface area and support volume required for the design, are found to correlate to cost and build time and are controlled through the topology optimization procedure. A novel methodology to consider each of these factors dynamically during the topology optimization procedure is presented. The methodology, based largely on the use of the spatial gradient of the density field, is developed in such a way that it does not leverage the finite element discretization scheme. This work investigates a problem that has not yet been explored in the literature: direct minimization of support material volume in density-based topology optimization. The entire methodology is formulated in a smooth and differentiable manner, and the sensitivity expressions required by gradient based optimization solvers are presented. A series of example problems are provided to demonstrate the efficacy of the proposed methodology.